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Effects of Weighted Sled Towing With Heavy Versus Light Load on Sprint Acceleration Ability
Abstract
Weighted sled towing is used by athletes to improve sprint acceleration ability. The typical coaching recommendation is to use relatively light loads, as excessively heavy loads are hypothesized to disrupt running mechanics and be detrimental to sprint performance. However, this coaching recommendation has not been empirically tested. This study compared the effects of weighted sled towing with two different external loads on sprint acceleration ability. Twenty-one physically active men were randomly allocated to heavy- (n = 10) or light-load weighted sled towing (n = 11) groups. All subjects participated in two training sessions per week for 8 weeks. The subjects in the heavy and light groups performed weighted sled towing using external loads that reduced sprint velocity by ∼30% and ∼10%, respectively. Before and after the training, the subjects performed a 10-m sprint test, in which split time was measured at 5 and 10 m from the start. The heavy group significantly improved both the 5- and 10-m sprint time by 5.7 ± 5.7% and 5.0 ± 3.5%, respectively (P < 0.05), whereas only 10-m sprint time was improved significantly by 3.0 ± 3.5% (P < 0.05) in the light group. No significant differences were found between the groups in the changes in 5-m and 10-m sprint time from pre- to post-training. These results question the notion that training loads that induce greater than 10% reduction in sprint velocity would negatively affect sprint performance, and point out the potential benefit of using a heavier load for weighted sled towing.
... Of the 27 studies that passed the first filter, the full text of 1 could not be accessed, and of the remaining 26 studies, twelve were excluded due to wrong intervention (n = 5), wrong design (n = 2), wrong population (n = 3), wrong analysis (n = 1), and study replication (n = 1). Finally, fourteen studies (Escobar Álvarez et al., 2021;Grazioli et al., 2020Grazioli et al., , 2023Harrison and Bourke, 2009;Hasan et al., 2021;Kawamori et al., 2014;Lahti et al., 2020;Lahti et al., 2020;Loturco et al., 2017;Luteberget et al., 2015;McMorrow et al., 2019;Morin et al., 2017;Panascì et al., 2023;Sinclair et al., 2021) met the eligibility criteria for inclusion in this systematic review with meta-analysis ( Fig. 1). No additional studies were identified following the grey literature search and citation search. ...
... A total of 344 participants from ten randomized controlled trials were included (Escobar Álvarez et al., 2021;Grazioli et al., 2020Grazioli et al., , 2023Harrison and Bourke, 2009;Hasan et al., 2021;Kawamori et al., 2014;Loturco et al., 2017;Morin et al., 2017;Panascì et al., 2023;Sinclair et al., 2021), and four non-randomized controlled trial (Lahti et al., 2020;Lahti et al., 2020;Luteberget et al., 2015;McMorrow et al., 2019). The age of the participants varied between 18.7 ± 0.6 (Luteberget et al., 2015;Sinclair et al., 2021) to 27.7 ± 4.5 (Panascì et al., 2023). ...
... The age of the participants varied between 18.7 ± 0.6 (Luteberget et al., 2015;Sinclair et al., 2021) to 27.7 ± 4.5 (Panascì et al., 2023). Regarding sports modality, eight studies considered soccer (Grazioli et al., 2020(Grazioli et al., , 2023Hasan et al., 2021;Kawamori et al., 2014;Lahti et al., 2020;Loturco et al., 2017;McMorrow et al., 2019;Morin et al., 2017), five rugby (Escobar Álvarez et al., 2021;Harrison and Bourke, 2009;Lahti et al., 2020;Panascì et al., 2023;Sinclair et al., 2021), one handball (Luteberget et al., 2015), one basketball (Kawamori et al., 2014), and one field hockey (Kawamori et al., 2014). Training planning con-sidered from five (Loturco et al., 2017) up to eleven weeks (Grazioli et al., 2020), with frequencies from one (Grazioli et al., 2020;Lahti et al., 2020) to three weekly sessions (Loturco et al., 2017). ...
Objective
This systematic review and meta-analysis aimed to examine the effects of resistance sled training (RST) on sprint performance in team sport athletes.
Methods
A systematic search was conducted in the electronic databases MEDLINE, Sportdiscus, Scopus and Web of Science from inception until October, 2023. Randomized or non-randomized controlled clinical trials that included collective field sports athletes who were trained with sled drag were included to evaluate the effectiveness of the training on performance in speed tests. Independent reviewer selected the studies with www.rayyan.ai, extracted the data, performed the risk-of-bias assessment, and methodological quality. The sprint time at distances of 5, 10 and 20 m were included for the meta-analysis. A random-effects model, standardized mean difference, and standard deviation were used for meta-analysis.
Results
Fourteen studies involving 344 participants were selected (overall risk: high risk; methodological quality: moderate quality). Meta-analysis revealed statistically significant effects in favor of RST on 5 m (SMD = -0.87; 95% CI = -1.58 to -0.16; p = 0.02) and 10 m (SMD = -0.40; 95% CI = -0.78 to -0.03; p = 0.04). However, there are no significant effects on 20 m (SMD = -0.34; 95% CI = -0.73 to 0.06 p = 0.1).
Conclusion
These results indicate that RST improves performance mainly in the short distance, suggesting that RST is a viable training method to improve athletic performance in team sports.
... During sprint acceleration, it is crucial to also consider the spatiotemporal parameters, such as step frequency (SF), step length (SL), flight time (FT), contact time (CT), and kinematic (joint and segment angles) because they are critical determinants of performance. Frequently, a decrease in SL, SF, and FT and an increase in CT during acute sprint towing trials (i.e., loaded vs. URS) (6,16,18,31) or long-term RSS training with low loads (14,35) has been reported. ...
... In most cross-sectional studies, the load for sled pulling is prescribed as a percentage of BM or as the load necessary for a desired reduction in maximum sprint velocity (v dec ). Some coaches and practitioners traditionally recommended performing RSS pulling with relatively light loads, which correspond to #10% of BM, or loads that reduce running velocity by #10% (14). However, because of differences in strength, gender, and training history across athletes, the v dec approach has been suggested as a more appropriate way to prescribe the loads for each individual in connection to %BM (7). ...
... This is in agreement with Petrakos et al. (26) who concluded that training with light loads and URS may not provide a sufficient stimulus for improving the sprint acceleration phase especially in already well-trained athletes. The latter could be derived from the fact that RSS training provides a sufficient stimulus for improving sprint acceleration performance because it causes mechanical adaptations, such as higher horizontal force generation capability and greater mechanical effectiveness of force application, and not because it is specific to sprint patterns (14). A sufficient stimulus for improving the sprint acceleration phase could be provided because of the additional resistive stimulus at heavier loads during RSS towing in anteroposterior direction and/or the potential of subjects to increase the efficiency of force application. ...
Stavridis, I, Ekizos, A, Zisi, M, Agilara, GO , Tsolakis, C, Terzis, G, and Paradisis, G. The effects of heavy resisted sled pulling on sprint mechanics and spatiotemporal parameters. J Strength Cond Res 37(12): 2346-2353, 2023-This study examines the effects of 2 resisted sled sprinting (RSS) training programs: with a load corresponding to the running velocity associated with the apex of the individual velocity-power relationship (50%vdec), with a load equal to 10% of body mass (10% BM), and of an unresisted sprint training (URS). We measured the 30-m sprint performance in intervals of 5 m examining sprint acceleration, mechanical properties (theoretical maximal horizontal power [Pmax], force [F0], velocity [v0], slope of the force-velocity relationship [SFv], maximal ratio of horizontal-to-resultant force [RFmax], rate of decrease in RF [Drf]), and spatiotemporal parameters (step frequency [SF], step length [SL], flight time [FT], and contact time [CT]). Twenty-seven sprinters were randomly assigned into the 50%vdec , 10% BM, and URS groups, performing 12 sessions over 6 consecutive weeks (2 sets of 5 sprints per session). The 50%vdec group significantly improved (p < 0.05) their performance in all 30-m intervals. Posttraining, the 50%vdec group showed significantly increased Pmax, F0, and RFmax (mean differences: 1.46 ± 1.70 W·kg−1, 0.51 ± 0.68 N·kg−1, and 0.17 ± 0.18%, respectively), compared with pretraining. The 50%vdec group achieved higher SF, whereas FT decreased postintervention. No significant changes (p > 0.05) were found in the performance and mechanical and spatiotemporal variables in the other groups. In conclusion, RSS training with a load of 50%vdec provides an effective loading stimulus to induce adaptations that improve sprint acceleration performance. The improvements are explained by greater amounts of force and power, efficient force application, and higher step frequencies.
... In general, strength and sprint performances are developed using a myriad of training strategies, including traditional heavy-resistance training (18,44,105), explosive ballistic and nonballistic exercises (70,80), speed training and sprint drills, resisted and traditional speed training (61,76), and plyometrics (31,105). Specifically, sprint training modes have been classified into 3 distinct subgroups (Table 1), based on their "task-specificity" (2,90,100): (a) primary methods, those simulating the "traditional" sprint pattern (sprint-technique drills, stride length and frequency exercises, and sprints of varying distances and intensities); (b) secondary methods, those simulating sprinting actions with certain overload or degree of assistance (resisted or assisted methods, respectively); and (c) tertiary methods, characterized by nonspecific sprint development protocols (resistance training, plyometric training, complex and contrast training, etc.) (100). ...
... Contradictory results are found in the literature possibly because of different loading conditions and training strategies, level of participants, testing protocols, and the use of methods and parameters with questionable reliability (106). Some studies showed positive effects on early sprint performance (16,61,87), whereas others reported no added benefits of VHST compared with ST with lighter loads (41,87,102) or even a decline in sprint performance after ST with heavier loads (16,102). In any case, strength and conditioning coaches must differentiate between resisted sprint training, whose main objective is to mimic sprinting for specificity of movement under low ranges of V dec (i.e., 10-20%), versus ST "per se", which, depending on the load magnitude, may have different effects on sprinting kinetics and kinematics. ...
... A recent study described loads of 45, 90, and 135% of BM as light, moderate, and heavy sled loads, with progressive V dec of 25, 50, and 75%, respectively (16). However, Kawamori et al. (61) considered sled loads of lighter magnitudes as "heavy sled loads" (30% V dec, which corresponds to ;50% BM), whereas another study defined 80% BM as a "very heavy sled load" condition (87). Finally, in a systematic review about resisted sprint training, sled loads were classified as light (,10% V dec ), moderate (10-15% V dec ), heavy (15-30% V dec ), and very heavy (.30% V dec ) loading conditions (99). ...
Sprinting is a key component for many individual and team sports. Therefore, to enhance sprint performance, various training methods are widely used by coaches and practitioners, including maximum sprint speed and resisted sprint training. Resisted sprinting with sled towing is a method that has recently received considerable attention from the sport science community. However, to date, no consensus exists regarding its acute and chronic effects in team sport athletes. This narrative review aimed to (a) review and analyze the mechanics of sprinting under unresisted and resisted conditions with a specific focus on team sport disciplines; (b) provide a thorough and
applied discussion on the importance of considering acute and chronic effects of sled loading on technique, electromyographic activity, and force production, as well as on the role of muscle architecture and neural factors in sled training; (c) analyze the effects of increasing sled loads during acceleration and maximum velocity phases on contact and flight phases, while concomitantly examining kinetic, kinematic, and neuromuscular aspects, because all these factors affect each other and cannot be properly understood in isolation.
... These methods are generally used to increase the propulsive forces of lower-body muscles potentially increasing stride length during sprinting (46). These training stimuli promote the development of both the vertical and horizontal force components of sprinting (40). One of the main variables to consider in RST is the load applied (2). ...
... BM or decreasing maximal velocity capacity more than 10% yielded changes in sprint kinematics (i.e., reduction of stride length and stride frequency) (1), this loading strategy also results in a performance improvement during the acceleration phase (1,46,69,77), no long-term negative effects on running technique have been observed (3,77). The training effects of sled towing with high loads (e.g., 30% BM) and concluded that this practice requires a higher horizontal force application have been reported in the literature (40,69,81). However, the same authors (40,69) performed an intervention with 2 experimental groups (low loads: 12.5-13% BM vs. high loads: 43-50% BM) without obtaining significant differences between the groups in the changes in sprint performance and horizontal rate of force development. ...
... The training effects of sled towing with high loads (e.g., 30% BM) and concluded that this practice requires a higher horizontal force application have been reported in the literature (40,69,81). However, the same authors (40,69) performed an intervention with 2 experimental groups (low loads: 12.5-13% BM vs. high loads: 43-50% BM) without obtaining significant differences between the groups in the changes in sprint performance and horizontal rate of force development. ...
Fernández-Galván, LM, Casado, A, García-Ramos, A, and Haff, GG. Effects of vest and sled resisted sprint training on sprint performance in young soccer players: A systematic review and meta-analysis. J Strength Cond Res XX(X): 000-000, 2022-The aim of the meta-analysis was to determine the effect of resisted sprint training (RST) on sprint performance in young (<20 years) soccer players and to analyze whether the training equipment (sled or vest) and magnitude of the resistive load (above or below 20% of body mass [BM]) influences the long-term adaptations in sprint performance. Resisted sprint training reduced the acceleration phase time [standardized mean difference (SMD) = -0.41], with greater reduction in sprint time occurring in response to applying resistance with a vest (SMD = -0.70) when compared with a sled (SMD = -0.27). Similar reductions were determined for resistive loads <20% (SMD = -0.55) and ≥20% of BM (SMD = -0.31). Full sprint time showed a small reduction after RST (SMD = -0.36), regardless of the training equipment (sled: SMD = -0.44; vest: SMD = -0.26) and resistive load (<20% of BM: SMD = -0.40 ≥ 20% of BM: SMD = -0.21). There was a small and nonsignificant reduction in the maximum-velocity phase after RST (SMD = -0.25), which was comparable when the training was performed with vest (SMD = -0.34) or sled (SMD = -0.22). No significant differences in the changes of the acceleration phase time (SMD = 0.05) or full sprint time (SMD = 0.08) were observed between the experimental (sled or vest RST) and control groups (only soccer or unresisted sprint training). In conclusion, RST is effective to improve sprint performance in young soccer players, but the improvements are not superior to unresisted sprint training.
... Accordingly, recent studies show that heavier loads (>30% BM and >30% v dec ) during RST are necessary to improve short-distance sprint performance among team-sport athletes. [16][17][18] RST based on %BM reduces the maximal velocity to different degrees, depending on the athlete's level of development and the actual resistance determined via friction. 19 The amount of velocity reduction, and not the absolute load, determines the training-induced stress and the type and magnitude of the adaptations. ...
... The RST group displayed similar or greater improvement in sprint performance than that reported in previous studies, 17,18,24,32 despite a shorter training period (4 vs 8-12 wk), supporting the effectiveness of the training protocol. This can be explained by several factors. ...
... This finding, combined with the large increases in F 0 , P max , and RF max , but not in v max , confirms that RST mainly improved sprint acceleration, which agrees with results from both adult and adolescent populations. 17,18,20,21,26,32,35 The fact that these changes were observed after only 4 weeks of training indicates that the changes were primarily driven by neural and technical improvements. This, in combination with our finding that horizontal jump length, but not vertical jump height, increased, demonstrates that the athletes appear to have disproportionately developed technical capacities, rather than gross physical ones. ...
Purpose: This study compared the effects of heavy resisted sprint training (RST) versus unresisted sprint training (UST) on sprint performance among adolescent soccer players.
Methods: Twenty-four male soccer players (age: 15.7 [0.5] y; body height: 175.7 [9.4] cm; body mass: 62.5 [9.2] kg) were randomly assigned to the RST group (n = 8), the UST group (n = 10), or the control group (n = 6). The UST group performed 8 × 20 m unresisted sprints twice weekly for 4 weeks, whereas the RST group performed 5 × 20-m heavy resisted sprints with a resistance set to maximize the horizontal power output. The control group performed only ordinary soccer training and match play. Magnitude-based decision and linear regression were used to analyze the data.
Results: The RST group improved sprint performances with moderate to large effect sizes (0.76–1.41) across all distances, both within and between groups (>92% beneficial effect likelihood). Conversely, there were no clear improvements in the UST and control groups. The RST evoked the largest improvements over short distances (6%–8%) and was strongly associated with increased maximum horizontal force capacities (r = .9). Players with a preintervention deficit in force capacity appeared to benefit the most from RST.
Conclusions: Four weeks of heavy RST led to superior improvements in short-sprint performance compared with UST among adolescent soccer players. Heavy RST, using a load individually selected to maximize horizontal power, is therefore highly recommended as a method to improve sprint acceleration in youth athletes.
... Furthermore, Kawamori et al. (14) reported significant decreases in 10-m sprint time after 8 training weeks for both light-load (a ;10% decrease in 10-m sprint velocity, ;13% BM) and heavy-load groups (a ;30% decrease in 10-m sprint velocity, ;43% BM). However, only the heavy-load group achieved significant reductions in the 5-m sprint time (14). Similarly, a brief report with soccer players showed unclear beneficial effects on 5-m (effect size [ES] 6 90% confidence interval [CI]: 0.36 6 0.64) and 20-m (ES: 0.19 6 0.42) sprint times after sled training with very-heavy loads (80% BM) compared with unresisted sprint training (18). ...
... Although no significant differences were found between loading conditions, G40% showed significant improvements in sprint performance (T10, T20, and T30), with greater ES and percentage of changes than other training protocols (Table 2 and Figure 1). In this line, a previous study observed that, after 16 training sessions of 5-15-m sprints, a 43% BM sled load produced improvements in 5-m and 10-m sprint times, whereas a sled load of 13% BM induced improvements only in 10-m sprint time (14). Thus, although only 2 Table 2 Values loading conditions were compared, the results of this study (14) partially support our findings, because the sled load of 40% BM showed the highest gains in sprint performance when compared with the remaining loading conditions. ...
... In this line, a previous study observed that, after 16 training sessions of 5-15-m sprints, a 43% BM sled load produced improvements in 5-m and 10-m sprint times, whereas a sled load of 13% BM induced improvements only in 10-m sprint time (14). Thus, although only 2 Table 2 Values loading conditions were compared, the results of this study (14) partially support our findings, because the sled load of 40% BM showed the highest gains in sprint performance when compared with the remaining loading conditions. Similarly to G40%, significant improvements (p , 0.05) in sprint acceleration (T10 and T30) were also found in G60%, although the magnitude of changes (D: 21.1 to 22.3%; ES: 0.22-0.52) in these variables were lower compared with G40% (D: 21.5 to 22.7%; ES: 0.39-0.87, ...
Rodríguez-Rosell, D, Sáez de Villarreal, E, Mora-Custodio, R, Asián-Clemente, JA, Bachero-Mena, B, Loturco, I, and Pareja-Blanco, F. Effects of different loading conditions during resisted sprint training on sprint performance. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to compare the effects of 5 loading conditions (0, 20, 40, 60, and 80% of body mass [BM]) during weighted sled sprint training on unresisted and resisted sprint performance and jump ability. Sixty physically active men were randomly assigned into 5 groups according to the overload used during sled sprint training: 0% (G0%, n = 12), 20% (G20%, n = 12), 40% (G40%, n = 12), 60% (G60%, n = 12), and 80% BM (G80%, n = 12). Pretraining and post-training assessments included: countermovement jump (CMJ), 30-m sprint without extra load, and 20-m sprint with 20, 40, 60, and 80% BM. All 5 experimental groups trained once a week for a period of 8 weeks completing the same training program (number of sessions, number of bouts, running distance in each sprint, rest intervals between repetitions, and total running distance), but with different sled loads (0, 20, 40, 60, and 80% BM). There was a significant "time × group" interaction for resisted sprint performance at 80% BM condition, where the G40% group attained improvements in performance and G80% worsened. Moreover, G40% increased performance in unresisted and the rest of loading conditions. In addition, G0% and G60% showed statistically significant increases in unresisted sprint performance. No relevant changes were observed in the other experimental groups. All groups showed significant improvements (p < 0.05-0.001) in CMJ height. Therefore, our findings suggest that resisted sprint training with moderate loads (i.e., 40% BM) may have a positive effect on unresisted and resisted sprint performance.
... Resisted sprint training (RST) is a common training method employed to develop sprint performance, in which athletes mimic the traditional sprint movements (ie, unloaded sprints) with an added resistance. 1 Previous studies confirmed that this training strategy is able to induce positive transfer to sprint performance, 2,3 indicating that resisted sprints can provide significant functional benefits and improvements in maximum speed performance, by inducing sprint-specific adaptations within the neuromuscular system. 4,5 Although there is a compelling body of evidence related to RST, 2,3 to date, it still exists a wide controversy concerning the optimal load for use during sled towing. Traditionally, external loads about 10% to 12.5% of body mass (BM) or not reducing the athlete's velocity by more than 10% from unresisted sprinting have been recommended. ...
... 3 In this regard, previous research has shown that heavy and very-heavy sled loads (≥40% BM or ≥30% velocity reduction) are potentially effective for improving sprinting acceleration due to greater horizontal force production and longer time to apply force. 5,10 For this reason, some authors have recommended the use of sled loads heavier than 20% BM for enhancing the initial acceleration phase, where velocity is low and resistive forces are high, and lighter loads (ie, <10% BM) for improving the maximal velocity phase, where velocity is higher and resistive forces are lower. 3,9 The vast majority of previous investigations on this topic have focused on the effects of RST in male subjects, either students, 9,11 recreational, 5,10,12 or elite 13 male athletes. ...
... 5,10 For this reason, some authors have recommended the use of sled loads heavier than 20% BM for enhancing the initial acceleration phase, where velocity is low and resistive forces are high, and lighter loads (ie, <10% BM) for improving the maximal velocity phase, where velocity is higher and resistive forces are lower. 3,9 The vast majority of previous investigations on this topic have focused on the effects of RST in male subjects, either students, 9,11 recreational, 5,10,12 or elite 13 male athletes. Nevertheless, little attention has been paid to the effects of this training strategy on the acceleration and maximum speed performance of female participants. ...
Purpose:
This study aimed to compare the effects of unresisted versus heavy sled sprint training (0% vs 40% body mass [BM]) on sprint performance in women. Moreover, the effects of the aforementioned loads on resisted sprint and jump performance were analyzed.
Methods:
Twenty-eight physically active women were randomly allocated into 2 groups: unloaded sprint training group (G0%, n = 14), and resisted sprint training with 40% BM group (G40%, n = 14). Pretraining and posttraining assessments included countermovement jump, unloaded 30-m sprint, and 20-m sprint with 20%, 40%, 60%, and 80% BM. Times to cover 0 to 10 (T10), 0 to 20 (T20), 0 to 30 (T30), 10 to 20 (T10-20), 20 to 30 (T20-30), and 10 to 30 m (T10-30) were recorded. Both groups were trained once a week for 8 weeks and completed the same training program, but with different loads (0% vs 40% BM).
Results:
No significant time × group interactions were observed. For unloaded sprint performance, G0% showed significant (P = .027) decreases only in T10-20, while G40% attained significant decreases in T30 (P = .021), T10-30 (P = .015), and T20-30 (P = .003). Regarding resisted sprint performance, G0% showed significant (P = .010) improvements only for the 20% BM condition. The G40% group attained significant improvements in all loading conditions (20%, 40%, 60%, and 80% BM). Both groups showed significant improvements (P < .001) in countermovement jump height.
Conclusions:
In physically active women, no significant differences in sprint and countermovement jump performance were detected after 8 weeks of resisted and unresisted sprint training programs. Future studies should, therefore, be devoted to how sprint training should be individualized to maximize performance.
... Twenty-one studies [21,[37][38][39][40][41][42][43][44][45][46][47][48][49][62][63][64][65][66][67][68] met the inclusion criteria. In total, this sample included 31 study groups of which 12 studies included a non-exposed control group [21, 37, 39, 43, 44, 47-49, 62, 66-68], with the remaining studies eligible for inclusion owing to the presence of a comparison group. ...
... Results displayed no differences between groups (p = 0.24; SMD − 0.13; 95% CI − 0.35 to 0.09) (Fig. 2). Twenty-nine study groups (n = 307) from 20 studies [21,[37][38][39][40][41][42][43][44][45][46][47][48][49][63][64][65][66][67][68] were included in the within-group analysis to determine the effect of RST on sprint time in the EA phase, with RST demonstrating a significant moderate improvement (p < 0.00001; SMD − 0.80; 95% CI − 1.01 to − 0.59) [Fig. 3]. ...
Developing the sprint performance of field-based invasion team sport (FITS) players is considered an essential training goal for FITS coaching practitioners, and thus numerous training methods are employed to elicit improvements. Although interest in resisted sprint training (RST) has grown considerably in recent times, there remains a lack of clarity around its utility in FITS, particularly regarding the use and effectiveness of heavier RST loads.
The aims of this review were to (1) compare RST to unresisted sprinting, (2) examine if RST can improve sprint performance and (3) investigate if external load and the method of load prescription influence the impact of RST in FITS players.
The systematic review and meta-analysis were conducted in compliance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The search strategy included terms for RST, RST modalities and FITS, and was applied to PubMed, SPORTDiscus, Web of Science and OpenGrey databases. Methodological quality and risk of bias associated with each study were assessed using the Physiotherapy Evidence Database scale (PEDro) and Cochrane Risk of Bias assessment tool respectively.
Twenty-one studies met the inclusion criteria for this review and were included in the final analysis. The primary between-group analysis revealed no differences between RST and unresisted sprinting for developing the early acceleration, late acceleration and maximum velocity sprint phases. Secondly, a within-group analysis found significant improvements for resisted sprint training in the early acceleration (standardised mean difference [SMD] − 0.80) and late acceleration (SMD − 0.28) sprint phases, with no change detected for the maximum velocity phase. Finally, significant moderate improvements were found for light (SMD − 0.69) and very heavy (SMD − 1.01) loads during early acceleration.
Resisted sprint training achieved similar improvements in sprint performance to those found for unresisted sprinting during the acceleration and maximum velocity sprint phases. Within-group findings show RST is an effective method for improving early acceleration and late acceleration performance of FITS players. Finally, a subgroup analysis supports the use of light and very heavy loads for increasing early acceleration performance, while also highlighting greater benefits associated with using the percentage velocity decrement loading method.
Open Science Framework, https://osf.io/thms7/.
... Light-resisted and unresisted sprints may enhance maximum speed, while sprints with resistance loads exceeding 30% of velocity decrements (20%-30% of body mass) may primarily enhance acceleration without any benefit to maximum speed. 5,[16][17][18] This may be due to excessive loading leading to longer ground contact times and less effective stretch-shortening cycle development. These factors likely explain why high loads result in greater adaptations in the acceleration phase, which is characterized by longer ground contact times. ...
... However, our findings are in contrast with those shown in other studies, which reported no significant differences in sprint time performance between the training modalities. 4,18 Notably, the discrepancies between our findings and those of the aforementioned studies may be due to the exercise prescription and the sled load 4 used, as well as the athletes involved. 4,25 Although the exact mechanism(s) underlying the observed greater training effect in the RSS group is still unclear, an explanation could be attributed to the sets and repetitions applied in the RSS training program. ...
Purpose:
To compare the effects between resisted sled sprint training (RSS) and unresisted sprint training (URS) on sprint and acceleration performance, vertical jump, and maximal strength during an 8-week period of preseason training.
Methods:
Twenty-six recreational active rugby players were randomly divided into either RSS or URS training groups and then performed 8 weeks of training, 2 sessions/wk of sprint-specific training program. The RSS group performed sprints by towing a sled overloaded with 12.6% of body mass for 2 of the 3 sets of 3 × 20-m sprints, plus one set was carried out with unresisted modality. The URS groups performed 3 sets of 3 × 20-m unresisted sprints. The measures of 10- and 30-m sprint times, vertical jump, and 3-repetition-maximum (3-RM) squat tests were performed at baseline and after 8 weeks.
Results:
Ten- and 30-m sprint times (P < .05 and ηp2>.44) improved significantly more in RSS than in URS. Both groups improved significantly in vertical jump and 3-RM squat tests; however, no significant differences (P > .1 and ηp2<.11) between groups were found.
Conclusions:
Our findings indicate that an 8-week program of RSS is more effective than URS for enhancing sprint time performance in male recreational active rugby players. In addition, these data suggest that a sled overload corresponding to 12.6% of body mass can induce positive effects on both acceleration and speed performance in recreational active rugby players.
... Additionally, the ability to modulate the sled's resistance allows for increased training specificity. Using heavier relative resistance levels has been associated with improvements in acceleration, while lighter resistances prioritize speed (9). ...
... A review done by Cahill et. al, noted how the resisted sled push is crucially different from other power focused exercises in that it places the athlete in a biomechanically unique position that allows them to train horizontal force production (4,5,9). Another study concluded that the resisted sled push could be particularly beneficial for sprinters, as the first phase of sprint races have a heavy emphasis on horizontal power (9,11). ...
Prior studies have demonstrated the beneficial effects of real-time data feedback (RTF) on athletic performance and motivation. Despite this evidence, the lack of practical means to implement RTF has hindered its widespread adoption. Recently, a smart-resisted sled push was developed to improve athletic power by utilizing electromagnetic motors as a resistance mechanism, coupled with an RTF display. Thirty healthy college-aged male football players were recruited in this randomized, crossover designed study to examine the efficacy of the RTF to improve power output. Participants were randomized into either group 1 (receiving RTF first then no RTF) or group 2 (receiving no RTF first then RTF) during six, 10-meter sled pushes with 3 min rest intervals. The first three pushes were set to an easier level (L1) and the last three were set to a resistance level twice that of the first three runs (L2). A one-month washout period was enforced. For trials 1-3 (L1) (p = 0.026, t = -2.34, ES = -0.428) and 4-6 (L2) (p = 0.035, t = -2.22, ES = -0.405), peak power output (the average peak power output over the course of trials 1-3 and 4-6) was greater in both groups when receiving RTF compared to no-RTF. These findings demonstrate the effectiveness of RTF in augmenting power output during performance training.
... Los estudios hablan de cargas que van desde el 10% hasta en ocasiones 100 120% del peso corporal del atleta. Si bien en el mundo del atletismo se utilizan cargas que consideran óptimas (10% peso corporal), debido a que se puede deteriorar la técnica de carrera; algunos autores como (Kawamori N, 2014) compararon los efectos del arrastre del trineo con peso con 2 cargas externas diferentes sobre la capacidad de aceleración del sprint. ...
... Estos resultados cuestionan la noción de que las cargas de entrenamiento que inducen una reducción de más del 10% en la velocidad de sprint afectarían negativamente el rendimiento de sprint y señalan el beneficio potencial de usar una carga más pesada para el arrastre del trineo con peso. (Kawamori N, 2014). ...
Inevitably, the inadequate practice of sports is associated with the appearance of injuries, and as the number of people who practice sports increases, these figures continue to rise. Field hockey is not exempt from this, due to the popularity and heyday of recent years, thanks to the sporting achievements of the national teams. It is important to highlight the change in the 2016 regulation, where the matches had a duration of 2 halves of 35' with 15' rest, to go on to play 4 quarters of 15' with 2' rest between the 1st and 2nd quarters and 3rd-4th, and 5´ between the 2nd and 3rd quarter. This made the intensity of the matches and, consequently, of the training sessions, greater and the players exposed to a greater number of injuries. Due to this, a complementary training proposal will be made.
Key Word: Adjuvant Training; Field hockey; Injuries; Training
... [7][8][9] Conversely, it has recently been suggested that heavier loads (from 40% to 80% BM) should be used to promote greater improvements at the opposite end of this continuum (ie, high-force/low-velocity portion). [9][10][11][12] Training under these loading conditions results in higher velocity decrements and increased contact times, 13,14 which may potentially induce negative effects on maximum velocity. 9 Nevertheless, these loading conditions also allow athletes to increase horizontal force production, which is key for sprint acceleration. ...
... 15 From a kinematic standpoint, heavier sled loads cause greater alterations in sprint technique (eg, decrease in step length, flight time, and running velocity; higher trunk lean and hip flexion) than lighter loads. 7,10,13,16,17 However, the great interindividual variability in sprint velocity decrements induced by each percentage of BM (interindividual coefficient of variations from 10% to 30%) should be highlighted. 18 Accordingly, it has been shown that differences in speed, strength, and power abilities may explain the individual responses during sled towing, since faster, stronger, and more powerful athletes require heavier sled loads (relative to % BM) to experience similar decrements in sprint velocity. ...
Purpose: The aim of the present study was to examine the changes in resisted sprint performance and kinematics provoked by different sled loads in elite sprinters and rugby players.
Methods: Eight elite male sprinters and 10 rugby union players performed 20-m sprints under three loading conditions (0%, 20%, and 60% body-mass [BM]). Sprint time was measured in 0-5, 5-10-, and 10-20-m, while stride length and hip, knee, and ankle angles were measured using an eight-sensor motion analysis system at the same distances.
Results: Sprinters were significantly faster than rugby players in unresisted and resisted sprints using 20% BM (effect size, “ES”[90% confidence limit, “CL”] range: 0.65[0.03;1.27]; 3.95[3.10;4.81]), but these differences were not significant at 60% BM. Compared to rugby players, sprinters showed lower velocity loss decrement in resisted sprints using 20% BM (ES[90%CL] range: 0.75[0.06;1.44]; 2.43[0.83;4.02], but higher velocity decrement loss using 60% BM (ES[90%CL] range: 1.13[0.43;1.82]; 1.46[0.81;2.11]). No significant differences were detected in stride length between sprinters and rugby players for any sprint condition (ES[90%CL] range: 0.02[-0.72;0.76]; 0.84[0.13;1.54]). Rugby players showed higher hip flexion in resisted sprints (ES[90%CL] range: 0.30[-0.54;1.14]; 1.17[0.20;2.15]) and lower plantar flexion in both unresisted and resisted sprints (ES[90%CL] range: 0.78[0.18;1.38]; 1.69[1.00;2.38] than sprinters.
Conclusions: The alterations induced by resisted sprints in sprint velocity and running technique differed between sprinters and rugby players. Some caution should be taken with general sled loads prescriptions, especially when relative loads are based on distinct percentages of BM, as training responses vary among sports and individuals.
... Specific to sled towing, sprint phase adaptation is related to the resistive stimulus, with heavier loads eliciting greatest gains in early acceleration, and lighter loads or unresisted sprinting benefiting the latter phases and maximal velocity. 2,8,9 Therefore, FV profiles and resisted load-velocity (LV) profiles, both of which have demonstrated high linearity and reliability, have increased in popularity recently to provide a more targeted approach to speed development. 5,6,10,11 Earlier research on ST used primarily absolute or % BM loads to examine the acute kinematic effects specific to technical sprint competency. ...
... Heavier loading parameters have been shown to increase horizontal force and elicit enhanced acceleration performance in comparison to lighter loads. 6,8,9,15,17,18 Therefore, current loading practices by S&C may be inadequate to achieve their desired adaptation for short distance sprint performance. 19 However, for longer sprints (> 20 yards) the loading parameters may be too heavy to elicit optimal changes specific to the latter phases of sprinting. ...
The purpose of this study was to assess current perceptions of strength and conditioning coaches’ use of sled towing (ST) as part of their training programs. One-hundred and twenty-five coaches responded to a survey of their ST practices. Themes investigated included the primary purpose and usefulness of using ST, the loads used in short and long distances, rest times between sprints, total volume of ST sprints per session, frequency of ST activity each month, and whether coaches engaged in force-velocity profiling in ST sprints. Eighty percent of coaches either agreed or strongly agreed that ST is a useful intervention tool for improving athletic performance. Speed strength was the physiological adaptation most sought after to improve (n = 75) followed by power (n = 72). Bodyweight (BW) loads of 20% were the most common across all distances. The two most common rest times given between each ST repetition were one to two minutes (n = 37) and two to three minutes (n = 37). The most common volume responses for individual training sessions were five to eight sprints (n = 52) and three to five times per month, respectively. These data suggest strength and conditioning coaches view ST as an integral part of programming, primarily use loads of 20% BW for both short and long sprints and seek to optimize a number of different physiological adaptations. The majority of coaches have a favorable view of ST (88%); however, current training parameters used by strength and conditioning coaches may be inadequate to achieve their desired adaptations.
... Through knowledge of the mechanical variables associated with sprint performance, authors have highlighted the improvement in players' ability to apply maximum horizontal force (FH 0 ), PH max and speed variables (i.e., V max and VH 0 ) following weighted sprint training (21-24). Consequently, this type of training would improve sprint performance over 30 m and intermediate times (22,24,25). The loads used for weighted sprints can be informed by a percentage of the body mass (22,24) or by a percentage of the speed variables (i.e., V max or VH 0 ) (21, 23, 26). ...
Background
Time to perform 40-yard dash (40-yd) is a performance criterion in American football. Sprinting ability is strongly correlated with maximal values of horizontal power (PHmax), Force (FH0) and Velocity (VH0). While numerous methods for developing sprint speed exist, few studies have focused on the effects of periodizations on the sprinting mechanical variables in young talented American football players.
Objective
this study aimed to compare the effects of block (BP) and undulating (UP) training periodization modalities on 40-yard dash performance.
Method
27 players from the Young French League of American football (17.1 ± 0.9 y, 179.9 ± 5.5 cm, 81.1 ± 14.9 kg) were randomly assigned in either the BP (n = 15) or UP (n = 12) group. Anthropometric characteristics, 40-yd performance, maximal velocity (Vmax), PHmax, FH0 and VH0 were assessed before and after 10-wk intervention period.
Results
Training resulted in the 40-yd performance increase of 3.72% (p < 0.001) and significant changes in Vmax (+ = 6.13 ± 5.62%, p < 0.001) and VH0 values (+2.68 ± 4.14%, p = 0.004). BP intervention leaded higher improvements in time to perform 40-yd (4.45 ± 2.06 vs. 3.02 ± 1.93%, p < 0.001) and Vmax (7.30 ± 6.63% vs. 4.54 ± 4.10%, p = 0.002,) compared to UP. No periodization effect was found in changes of VH0 (BP: 3.42 ± 4.31% vs. UP: 1.48 ± 3.88, p = 0.214).
Conclusion
Our results showed that BP and UP were effective to increase sprint performance. Despite a similar training load, the block periodization of training had better effects on 40-yd performance compared to undulating training periodization in this population of talented young American football players.
... In this sense, some approaches recommend using light loads to avoid mechanical disturbances and maintain the natural sprint mechanics observed under free sprint conditions (11,12,22). These approaches, involving loads less than 20% of body weight or with velocity losses under 10%, are usually applied over short distances of 20 and 30 meters per set (42)(43)(44)(45). However, while light loads are effective in preserving natural sprint mechanics, they may lack the specificity needed/required for the sustained replication of initial contact conditions. ...
Introduction
This study analyzed the impact of various overload conditions on sprint performance compared to free sprinting, aiming to identify the loading scenarios that most closely replicate the mechanics of unresisted sprints across the full acceleration spectrum. While velocity-based training methods have gained popularity, their applicability is limited to the plateau phase of sprinting.
Methods
To address this limitation, we employed cluster analysis to identify scenarios that best replicate the mechanical characteristics of free sprinting across various overload conditions. Sixteen experienced male sprinters performed sprints under six conditions: unresisted, overspeed (OS) and four overloaded conditions inducing a velocity loss (VL) of 10%, 25%, 50% and 65% using a resistance training device with intelligent drag technology. Ground reaction forces and spatiotemporal parameters were recorded for all steps using a 52-meter force plate system for all sprint conditions.
Results
Cluster analysis revealed four distinct groups aligning with established sprint phases: initial contact, early-acceleration, mid-acceleration, and late-acceleration. Results showed that heavier loads prolonged the mechanical conditions typical of early-acceleration and mid-acceleration phases, potentially enhancing training stimuli for these crucial sprint components of sprint performance. Specifically, VL50 and VL65 loads extended the early-acceleration phase mechanics to steps 7–8, compared to steps 2–4 for lighter loads. Conversely, lighter loads more effectively replicated late-acceleration mechanics, but only after covering substantial distances, typically from the 11- to 29-meter mark onwards.
Discussion
These findings suggest that tailoring overload conditions to specific sprint phases can optimize sprint-specific training and provide coaches with precise strategies for load prescription. These insights offer a more nuanced approach to resistance-based sprint training by accounting for every step across all acceleration phases, rather than focusing solely on the plateau phase, which accounts for only 20–30% of the steps collected during initial contact to peak velocity depending on the analyzed overload condition.
... If we want athletes to be more explosive and capable of moving at higher speeds, they must be able to apply greater force to the ground [42]. Consequently, more force is needed for more acceleration [43,44]. If the force component is limited by not providing adequate loads (e.g., using only resistive loads that are too light on the sled), RST would be used both out of context and not up to its full potential. ...
Background/Objectives: The aim of this study was to investigate the effects of a six-week integrated resisted sprint training (IRST) program on sprint performance and vertical jump height in a sample of U-14 male football players. This study also explored the potential benefits of incorporating variable resistive loads during pre-peak height velocity (pre-PHV) developmental stages, a period often overlooked in the training of young athletes. The IRST program alternated between heavy and light resistive sled loads to enhance sprint and jump capabilities, which are critical components of athletic performance in football. Methods: Nineteen healthy male football players (age: 13 ± 0.63 years) were divided into an experimental group (E, n = 10) and a control group (C, n = 9). The experimental group followed the IRST protocol, involving sled sprints with varying resistive loads (10–115% of the body mass) over specific distances, while the control group engaged in traditional unresisted sprint training. The sprint performance was assessed using 30 m sprint times, and the vertical jump height was measured using countermovement jump (CMJ) data collected via a force platform. Anthropometric measures and peak height velocity (aPHV) estimates were also recorded pre- and post-intervention. Results: The experimental group demonstrated significant improvements in 30 m sprint times (mean difference: −0.29 s; p < 0.01). Additionally, CMJ data revealed a positive trend in the take-off velocity and maximum concentric power, with an increase in jump height (mean difference: +0.44 cm). These results suggest enhanced sprint and explosive power capabilities following the IRST intervention. Conclusions: The findings suggest that the IRST program is an effective training method for enhancing sprint performance and maintaining jump capabilities in young football players. This approach highlights the importance of integrating variable resistance training in pre-PHV athletes to promote athletic development while ensuring safety and effectiveness.
... Conversely, Whelan et al. (2014) reported that weighted sled pulls <30% body mass is insufficient to elicit a fatigue effect or PAP response. It is suggested that weighted sled towing may assist athletes in producing larger horizontal or impact ground reaction forces to increase acceleration performance (Kawamori et al., 2014). Previous research has employed an isotonic resistance training load of 75-95% 1RM, or 75% of body mass, which has been successful in eliciting a PAP response in sprint performance (Winwood et al., 2016). ...
Resisted and assisted training methods aim to increase neural activation, or post-activation potentiation (PAP), to enhance sprint performance. A preloaded stimulus causes a temporary performance increase that is more significant than what warm-up alone can provide. Resistance activities have traditionally been used to induce post-activation potentiation. Little is known when assisted and resisted sprints are combined and their effect on PAP. Therefore, this study aimed to examine the acute potentiating effect of combined resisted and assisted sprints on subsequent 20 m sprint performance. Sixteen physically active young males performed a baseline 20 m sprint followed by four assisted 20 m and four 20 m resisted sprints using a bungee cord. After the assisted-resisted stimulus, the participants performed one 20 m sprint at 4, 6, and 8 minutes. There was no significant improvement in 5, 10, or 20-m sprint times following the assisted-resisted stimulus. Therefore, the additive effect of assisted-resisted sprints failed to induce post-activation potential. The additive effect of assisted-resisted sprints could not induce post-activation potential to enhance subsequence sprint performance.
... It can enhance the horizontal force output in the AP direction and mechanical efficiency by adjusting the trunk angle to effectively accelerate the body forward [40,[44][45][46][47][48]. Recent studies have shown that loads of 30-50% sprint velocity decrement (Vdec; a load of percentage decrement to the maximum sprint velocity) are effective for initial acceleration mechanics (0-20 m) and have been used in practice and research [28,40,41,47,[49][50][51]. However, traditional resisted sprint training has been biased toward improving mechanics and single sprint performance without considering the metabolic stresses required by soccer players. ...
This study explored the impact of short rest intervals on resisted sprint training in elite youth soccer players, specifically targeting enhanced initial-phase explosive acceleration without altering sprint mechanics. Fifteen U19 soccer players participated in a randomized crossover design trial, executing two sprint conditions: RST2M (6 sprints of 20 m resisted sprints with 2 min rest intervals) and RST40S (6 sprints of 20 m resisted sprints with 40 s rest intervals), both under a load equivalent to 30% of sprint velocity decrement using a resistance device. To gauge neuromuscular fatigue, countermovement jumps were performed before and after each session, and the fatigue index along with sprint decrement percentage were calculated. Interestingly, the results indicated no significant differences in sprint performance or mechanical variables between RST2M and RST40S, suggesting that the duration of rest intervals did not affect the outcomes. Horizontal resistance appeared to mitigate compensatory patterns typically induced by fatigue in short rest periods, maintaining effective joint movement and hip extensor recruitment necessary for producing horizontal ground forces. These findings propose a novel training strategy that could simultaneously enhance sprint mechanics during initial accelerations and repeated sprint abilities for elite youth soccer players—a methodology not previously employed
... Currently, most research on resisted and assisted sprint training involves implementing training interventions for athletes using tools such as resistance sleds, elastic bands, resistance parachutes, and weighted vests. These studies primarily focus on assessing changes in athletes' sprint times and performance, with the aim of evaluating post-activation performance enhancement or longitudinal training effects [13][14][15][16][17]. The majority of these investigations concentrate solely on changes over specific distances, without providing any insight into the kinematics and biomechanics of the study. ...
Resisted sprint and assisted sprint are the two main types of training methods used by athletes in sprint training, so optimizing resisted sprint training and assisted sprint training process is beneficial for improving athletes’ sprint performance. Kinematics is the most intuitive parameter that reflects the quality of training during running process, and it is particularly important to analyze the gait of athletes during resisted and assisted sprint process. Therefore, this paper investigates the effects of resisted and assisted sprint on the sprint kinematics of sprinters in the first 30 meters to demonstrate the targeted effects of resisted and assisted sprint training. The experimental results show that compared to the unloaded running, male collegiate sprinters increase their total step count, decrease their step length, increase their step time, increase their contact time, whereas have almost no change in the flight time when performing the 30-m resisted sprint. Male collegiate sprinters decrease their total step count, increase their step length, increase their step time, decrease their contact time and increase their flight time, when performing the 30-m assisted sprint. In addition, it is found that resisted sprint training is beneficial for improving the athletes’ power and explosiveness during the acceleration phase, thereby improving acceleration ability. However, prolonged and frequent resisted sprint training may reduce the step length and step frequency of athletes. Assisted sprint training is beneficial for shortening the contact time of athletes, improving their step length and flight time, and enabling them to overspeed, thereby increasing their maximum speed ability.
... The appropriate load for ST, according to studies, is the one that decreases an athlete's velocity by greater than 10% from unloaded sprinting, as it can cause signifi cant alterations in the sprinting method of the athlete [34]. Adding weights to sleds has been employed as a means to enhance sprint acceleration ability, and it has been observed that relatively heavier loads could be more advantageous than lighter loads [35][36][37][38][39]. Overall, ST including resisted ST and heavy sled towing has been shown to positively affect bone health and mechanical loading and might be a practical training strategy for enhancing sprinting performance and bone health. ...
Specific impact of sprint training (ST) on bone health has yet to be fully explored, in particular how it affects bone mineral density (BMD) and bone structure.
Aim . To investigate the ST and bone health relationship between athletes of different training intensities and nonathletes of different ages.
Materials and methods . A search of databases PubMed, Embase, and Pedro was conducted from January 2009 to August 2023. The full texts of all potentially relevant studies were obtained and evaluated by three independent reviewers for inclusion.
Results . The comprehensive review of eight studies indicates a positive influence of ST on bone health. Sprinters show higher cortical and trabecular BMD in the tibia than controls, with a noted age-related decline in BMD. Short distance runners demonstrate significantly better BMD, counter-movement jump performance, and grip strength compared to long-distance runners. These benefits are consistent across various age groups, including older athletes, with minimal age-related changes in mid-tibial BMD. ST is also associated with a 21% increase in tibial stress-strain index, indicating sustained bone strength, and a reduction in fracture risk in the elderly through downregulation of fracture-related microRNAs.
Conclusion . ST significantly enhances bone health, particularly in improving BMD and bone microarchitecture. Incorporating ST into exercise routines may benefit athletes and older individuals. Further research is essential to understand the mechanisms and develop optimal training protocols for bone health.
... Nevertheless, this result indicates the possibility that training using resisted sprints with an excessively long distance or duration would cause changes in movement pattern into a more vertical force application to the ground, which is detrimental to sprint performance [23,24,28]. A previous study reported that 8-week resisted sprint training program improved sprint acceleration performance with a decrease in vertical impulse [29]. Therefore, the phenomenon of more vertical force application near the maximal velocity in resisted sprint may not have adverse impacts on kinetic adaptations through resisted sprint training. ...
This study aimed to elucidate the influence of horizontal resistance loads on the spatiotemporal and ground reaction force (GRF) variables during maximal sprint acceleration. Nine male sprinters (20.2 ± 1.2 years; 175.3 ± 4.5 cm, 69.7 ± 6.1 kg) performed sprint-running with six loading conditions of one unresisted and five resisted loads of 4, 6, 8, 10, and 12 kg using a resistance training device with intelligent drag technology. During the trials, the GRFs for all steps were determined using a 50-m force plate system. The spatiotemporal and GRF variables at running velocity of every 0.5 m/s were obtained and compared across the loading conditions. The maximal running velocity under 0, 4, 6, 8, 10, and 12 kg loading conditions were 9.84 ± 0.41, 8.55 ± 0.41, 8.09 ± 0.33, 7.62 ± 0.34, 7.11 ± 0.31, and 6.71 ± 0.29 m/s, respectively. ANOVA revealed significant main effects of load on the measured variables (η² = 0.236–0.715, p < 0.05), except for stance-averaged anteroposterior GRF and braking impulse. However, the observed differences between the loading conditions were small, with approximately 4% (1.3–7.5%) for the GRF variables and approximately 9% (1.2–22.3%) for the spatiotemporal variables. The present study indicates that horizontal resistance load in sprint acceleration has little impact on the spatiotemporal and GRF variables at a given running velocity. In contrast to a general recommendation, one should adopt a heavy load in resisted sprint aiming to improve performance in the earlier stage of maximal sprint acceleration.
... Many training methods have been shown to be effective in improving sprint performance, such as resistance training (29,30,32,34,36), plyometric training (4,27,32), unloaded sprint training (1,32), and complex training (7). However, resisted sled training (RST) is one of the most used training methods for the development of sprint performance, specifically in the early acceleration phase (#20 m), independent of participant and load characteristics (1,3,6,12,20,25,26,28,38,40). Traditionally, RST involves performing a set number of maximal straight-line sprint efforts while pulling a sled device, to which discs can be added to increase the load, with the aim of inducing a certain performance loss with respect to the unloaded sprint (1,26). ...
Jiménez-Lozano, M, Yáñez-García, JM, Mora-Custodio, R, Valle-Salguero, A, Díez-Fernández, DM, Franco-Márquez, F, González-Badillo, JJ, and Rodríguez-Rosell, D. Load-time and load-speed relationship in the resisted sled sprint exercise: what independent variable most accurately determines the relative load? J Strength Cond Res 37(11): 2167–2177, 2023—The aims of this study were to analyze the load-speed and load-time relationships in the resisted sled sprint exercise using different variables as relative load and to estimate the decrement of speed sprint and the increase of sprint time across different loads. Thirty young healthy men performed a progressive loading test in the countermovement jump (CMJ) exercise to determinate the load that elicited a 2 m·s ⁻¹ peak velocity (PV2-load) and in the full squat exercise to obtain the 1 repetition maximum (1RM) value and the load that elicited a 1 m·s ⁻¹ mean velocity (V1-load). In addition, subjects performed a progressive loading test in the resisted sled sprint exercise, whereas time and instantaneous speed at 10 (T 10 and V 10 ) and 20 m (T 20 and V 20 ) were measured. The independent variables used were body mass (BM), 1RM and V1-load in the squat exercise, the PV2-Load in the loaded CMJ exercise, 1RM + BM, V1-Load + BM, and PV2-Load + BM. To analyze whether relationships were dependent on individual performance obtained in unloaded sprint, the total sample was divided into 3 subgroups: high performance (T 20 < 3.00 s), medium performance (T 20 :3.00–3.12 s), and low performance (T 20 > 3.12 seconds) groups. The independent variables showing the highest relationships with time and speed in 10 and 20 m were %BM, %BM + V1-load, and %BM + PV2-load. Statistically significant differences between performance groups in %DSS (decrease of sprint speed) and %IST (increase sprint time) in 20 m were found when %BM was used as relative load, whereas there were no significant differences between groups for %BM + PV2-load or %BM + V1-load. In conclusion, the use of %BM + PV2-load and %BM + V1-load should be considered as variables for monitoring the relative load in the resisted sled sprint exercise.
... Resisted sprints (i.e., loaded sleds) have been shown to increase both stride length and stride frequency and acute increase in forward trunk lean (improved position to generate horizontal impulse) during sprints <20m in team sport athletes and university students (Zafeiridis, et al., 2005;Cronin, et al., 2008;Makaruk, et al., 2013;Kawamori, et al., 2014b). In contrast, assisted methods have demonstrated increases in stride length and decreased stride frequency in track athletes (Petrakos, et al., 2016;Alcaraz, et al., 2018). ...
Within the football codes, sprint performance is considered an important capacity for success and is therefore targeted as an area of athletic development programmes. However, the concurrent and complex nature of physical preparation for the football codes presents several challenges for effective sprint development. This thesis aimed to evaluate and enhance the understanding of the development of sprint performance in football code athletes to support the delivery of best practices. This thesis is comprised of sequential sections presented through a series of chapters. First, systematic reviews with meta-analyses to evaluate the evidence base for the development of sprint performance (short- and medium-long distances). Second, a practitioner survey analysing the applied training practices and justifications for the organisation and evaluation of the sprint development. The last section provides observations and evaluation of profiling methods
for phase and distance-specific sprint performance using a case study of combined
training methodologies in elite male youth rugby league athletes.
The systematic review and meta-analysis showed sport-only training and short sprints with incomplete rest appear to be insufficient to enhance sprint performance in football code athletes. Instead, sprint development requires either or preferably a combined method approach to both improving sprinting skills (i.e., sprints performed with overload (physical or co-coordinative)) and the athlete's physical characteristics (i.e., plyometrics and resistance training). Combined with the surveys and case studies this research showed that a one size fits all approach to sprint development (i.e., exercises, loading ect.) is not applicable; instead, effective training strategies depend upon the individuals and context to it is applied. Therefore, the content of the training (e.g., training frequency, exercise selection, training load prescription) is highly variable in research and practice, but so is the training response. Applying frequent and embedded monitoring of key variables (i.e., mechanical profiling) can support personalised and potentially improved training practices. Sprint development in football code practice is challenging (particularly long-term) due to the complexity and at times, competing requirements of an athlete’s development. Therefore, if an individual or team of football code athletes aims to enhance sprint performance, it requires prioritisation from all the key stakeholders.
... 24 In general, our findings are consistent with and expand upon previous studies, which did not observe any significant interactions or differences when comparing the effects of RST under different %VL (including intrasession decrements) or %BM on linear sprint performance. 8,22,23 The absence of group-by-time interaction effects detected for speed-related abilities could be due to the high variability in individual training responses, as confirmed by the "true change" analysis 18 (Figures 1-3). When examining these figures, it is possible to note that, in both groups, we had distinct and opposite changes in 10-m sprint, CS, and COD speed performances, which may indicate that soccer players respond differently to the same RST condition. ...
Purpose:
We examined the effects of two 8-week resisted-sprint training programs under different magnitudes of velocity loss (VL) on the speed-related performance of highly trained soccer players.
Methods:
Twenty-one soccer players (age: 25.9 [5.4] y) were randomly assigned to 1 of 2 groups: (1) the "moderate-load group," players who trained with sled loads that induced 15%VL relative to unloaded sprint velocity (n = 11); and (2) the "heavy-load group," players who trained with sled loads that induced 40% VL relative to unloaded sprint velocity (n = 10). Linear sprint (10 m), curve sprint, change-of-direction speed, resisted-sprint performance at 15% VL and 40% VL, and vertical jumping ability were tested pretraining and posttraining. A 2-way repeated-measures analysis of variance was used to test for differences between groups. In addition, percentage changes were calculated for speed-related abilities and compared with their respective coefficients of variation to determine whether individual changes in performance were greater than the test variance (ie, "true change").
Results:
A main effect of time was detected for 10-m sprint, curve sprint, change-of-direction speed, and 15% VL and 40% VL resisted-sprint times, with significant decreases in sprint times (P = .003, P = .004, P = .05, P = .036, and P = .019, respectively). Jump variables did not change significantly over time. There were no group-by-time interactions for any tested variable (P > .05), but the "true change" analysis revealed meaningful individual changes in both groups.
Conclusions:
Both moderate- and heavy-sled loading conditions may optimize the development of speed-related abilities in highly trained soccer players. Nevertheless, resisted-sprint training responses may differ meaningfully when assessed on an individual basis.
... For example, the effectiveness of a training program is based on the principal of specificity, i.e., when the gains from strength and power training are translated into sprint-specific movements [8]. The training principle of specificity is also accomplished with a positive transfer of training to athletic performance and, in specific, the case where the training program emphasizes on a similar motor pattern and type of muscle contraction as the competitive movement [9], [19], [26]. A prerequisite for the optimization of resistance training in sprinting is to strictly implement individualized loads based on the practitioner's characteristics [22]. ...
The purpose of the study was to examine the effect of resisted sled sprints (RSS) on the biomechanical parameters of the first steps of short acceleration sprints. Five track and field athletes performed 10-m sprints using the semi-standing (SSS) and the 3-point (TPS) starting techniques. The RSS condition was conducted with a load of 9.7% ± 0.3 of body mass. Results of the 2 (start technique) × 2 (loading) × 3 (steps) revealed significant (p < .05) main effects on average step velocity. Main effects of loading and step were observed for contact time and step length, while a main effect of step was observed in the examined spatiotemporal parameters. No differences (p > .05) were evident for flight time and sled pulling force. In conclusion, regardless the starting technique, RSS should be controlled for the avoidance of the excessive loading that was observed at the sprint start.
... Several works showed that running sprint training coupled with horizontally oriented resistance improved sprint performance. For example, Kawamori et al. (14) recorded performance enhancements of 3-5% on a 10-m running sprint after 16 sessions of sledresisted training with load corresponding to 13 and 43% of body mass. Although using heavy-loaded sled fosters adaptations on the initial acceleration phase (reduction in 0-5-or 0-10-m times, increase in F 0 ; (5,24)), light to moderate loads have been shown to improve performance on the final acceleration phase (2,5). ...
Le Scouarnec, J, Samozino, P, Andrieu, B, Thubin, T, Morin, JB, and Favier, FB. Effects of repeated sprint training with progressive elastic resistance on sprint performance and anterior-posterior force production in elite young soccer players. J Strength Cond Res 36(6): 1675-1681, 2022-This study aimed to determine whether repeated sprint training with progressive high elastic resistance could improve sprint performance and anterior-posterior (AP) force production capacities of elite young soccer players. Seven elite U19 soccer players underwent 10 sessions of elastic-resisted repeated sprints on 8 weeks, whereas 8 U17 players from the same academy (control group) followed the same protocol without elastic bands. Sprint performance and mechanical parameters were recorded on a 30-m sprint before and after training. The control group did not show change for any of the measured variables. In contrast, the elastic-resisted training resulted in a significant improvement of the sprint time (-2.1 ± 1.3%; p = 0.026; Hedges' g = -0.49) and maximal velocity (Vmax; +3.9 ± 2%; p = 0.029; Hedges' g = 0.61) reached during the 30-m sprint. These enhancements were concurrent with an increase in the maximal power output related to AP force (Pmax; +4.9 ± 5.1%%; p = 0.026; Hedges' g = 0.42). Although the theoretical maximal AP force (F0) remained unchanged in both groups, there was a medium but nonsignificant increase in theoretical maximal velocity (V0; +3.7 ± 2.5%; p = 0.13; Hedges' g = 0.5) only in the elastic group. Therefore, the present results show that sprint capacity of elite young soccer players can be further improved by adding incremental resistance against runner displacement to raise the ability to produce AP force, rather at high velocity in the final phase of the acceleration.
... It is suggested that runners with lower sprinting ability produce greater vertical force relative to propulsive force during the acceleration phase and, thus, cannot run as fast. Kawamori et al. (2014) demonstrated that applying weighted sled towing as a training technique decreased the vertical force generated by runners and improved their sprinting capabilities. Furthermore, cycling with a high load/intensity has been shown to activate the hip extensor muscles considerably , which contributes to the production of propulsive force during running, and it has been demonstrated that bicycle sprint training improved the metabolism of lactate by runners (Oriishi et al., 2018). ...
Long-distance runners require aerobic capacity as well as sprinting ability for superior performance; however, the factors which determine the sprinting ability of long-distance runners remain undetermined. Therefore, the purpose of our study was to examine the association between thigh muscle size and sprinting ability in national-level male long-distance runners. Nineteen male long-distance runners with 5000 m personal-best times of 13:12.63–14:14.87 participated in this study, and transaxial images of their right thighs were collected using magnetic resonance imaging. The cross-sectional areas of the quadriceps femoris, hamstrings, and adductor muscles were calculated from the transaxial images at 30%, 50%, and 70% of the distance from the greater trochanter to the lower edge of the femur; these areas were normalized by body mass. Sprint times for 100 m and 400 m were recorded on an all-weather track. The results revealed positive correlations between the normalized cross-sectional areas of the quadriceps femoris at 50% and 70% of the thigh length and the 100 m (r = 0.666, p = 0.002 and r = 0.531, p = 0.019, respectively) and 400 m sprint times (r = 0.769, p < 0.001 and r = 0.580, p = 0.009, respectively); hence, the larger the quadriceps, the slower the sprint speed. However, no association was found between the normalized cross-sectional areas of the hamstrings or adductor muscles and sprinting performance. Therefore, running motions which activate the quadriceps femoris much more than the hamstrings and adductor muscles should be avoided by national-level long-distance runners.
... The literature suggests that the ability to generate large magnitudes of ground reaction force in the horizontal direction is an important component of acceleration performance [27]. While success within sprinting events relies heavily on both the ability to accelerate rapidly and through achieving and maintaining high running velocities [28], studies are also reporting the importance of horizontal force development for CoD performance [29] and sport-specific jumping ability [30]. Based on these observations, sprints over 10-30 m are usually performed for testing and training purposes. ...
Traditional neuromuscular tests (e.g., jumping and sprinting tasks) are useful to assess athletic performance, but the basic outcomes (e.g., jump height, sprint time) offer only a limited amount of information, warranting a more detailed approach to performance testing. With a more analytical approach and biomechanical testing, neuromuscular function can be assessed in-depth. In this article, we review the utility of selected biomechanical variables (eccentric utilization ratio, force–velocity relationship, reactive strength index, and bilateral deficit) for monitoring sport performance and training optimization. These variables still represent a macroscopic level of analysis, but provide a more detailed insight into an individual’s neuromuscular capabilities, which can be overlooked in conventional testing. Although the aforementioned “alternative” variables are more complex in biomechanical terms, they are relatively simple to examine, with no need for additional technology other than what is already necessary for performing the conventional tests (for example, even smartphones can be used in many cases). In this review, we conclude that, with the exception of the eccentric utilization ratio, all of the selected variables have some potential for evaluating sport performance.
... Together with stride frequency, SL determines acceleration and maximal speed, which are both important performance determining factors not only in athletics [5], but also in team sports like football [6]. Therefore, optimization of SL (and frequency) is of interest to athletes, coaches, and scientists and, consequently, it has been measured in many studies on performance [5,[7][8][9][10][11][12] and training [13][14][15][16]. To this end, video or optoelectronic systems have commonly been used and, in general, these require an unobstructed view of the athlete, are relatively expensive, and analysis can be quite laborious. ...
Inertial measurement units (IMUs) fixed to the lower limbs have been reported to provide accurate estimates of stride lengths (SLs) during walking. Due to technical challenges, validation of such estimates in running is generally limited to speeds (well) below 5 m·s⁻¹. However, athletes sprinting at (sub)maximal effort already surpass 5 m·s⁻¹ after a few strides. The present study aimed to develop and validate IMU-derived SLs during maximal linear overground sprints. Recreational athletes (n = 21) completed two sets of three 35 m sprints executed at 60, 80, and 100% of subjective effort, with an IMU on the instep of each shoe. Reference SLs from start to ~30 m were obtained with a series of video cameras. SLs from IMUs were obtained by double integration of horizontal acceleration with a zero-velocity update, corrected for acceleration artefacts at touch-down of the feet. Peak sprint speeds (mean ± SD) reached at the three levels of effort were 7.02 ± 0.80, 7.65 ± 0.77, and 8.42 ± 0.85 m·s⁻¹, respectively. Biases (±Limits of Agreement) of SLs obtained from all participants during sprints at 60, 80, and 100% effort were 0.01% (±6.33%), −0.75% (±6.39%), and −2.51% (±8.54%), respectively. In conclusion, in recreational athletes wearing IMUs tightly fixed to their shoes, stride length can be estimated with reasonable accuracy during maximal linear sprint acceleration.
... [21] The study was conducted according to the Declaration of Helsinki and the protocol was approved by the institutional ethics ES = 0.50) to 'moderate' improvements in maximal sprint velocity (2.4%, ES = 0.80). In strength-trained or team sport individuals, 'Moderate' (10)(11)(12)(13)(14)(15)(16)(17)(18)(19).9%BM) to 'very heavy' (30% BM) sled loads provide 'trivial' to 'extremely large' improvements in acceleration performance (0.5-9.1%, ES = 0.14-4.00). On the other hand, Rumpf et al. [20] showed that this type of training increases velocity via increased step frequency, increased horizontal force and power production. ...
The purpose of this study was to examine the effects of non-resisted (NRS) and partner-towing resisted (RS) sprint training on legs explosive force, sprint performance and sprint kinematic parameters. Sixteen young elite soccer players (age 16.6 ± 0.2 years, height 175.6 ± 5.7 cm, and body mass 67.6 ± 8.2 kg) were randomly allocated to two training groups: resisted sprint RS (n = 7) and non-resisted sprint NRS (n = 9). The RS group followed a six-week sprint training programme consisting of two "sprint training sessions" per week in addition to their usual soccer training. The NRS group followed a similar sprint training programme, replicating the distances of sprints but without any added resistance. All players were assessed before and after training: vertical and horizontal jumping (countermovement jump (CMJ), squat jump (SJ), and 5-jump test (5JT)), 30 m sprint performance (5, 10, and 20 m split times), and running kinematics (stride length and frequency). In the RS group significant (p < 0.05) changes were: decreased sprint time for 0-5 m, 0-10 m and 0-30 m (-6.31, -5.73 and -2.00%; effect size (ES) = 0.70, 1.00 and 0.41, respectively); higher peak jumping height (4.23% and 3.59%; ES = 0.35 and 0.37, for SJ and CMJ respectively); and 5JT (3.10%; ES = 0.44); and increased stride frequency (3.96%; ES = 0.76). In the NRS group, significant (p < 0.05) changes were: decreased sprint time at 0-30 m (-1.34%, ES = 0.33) and increased stride length (1.21%; ES = 0.17). RS training (partner towing) for six weeks in young soccer players showed more effective performances in sprint, stride frequency and lower-limb explosive force, while NRS training improved sprint performance at 0-30 m and stride length. Consequently, coaches and physical trainers should consider including RS training as part of their sprint training to ensure optimal sprint performance.
... In contrast, decreasing the movement speed through resisted sprinting methods such as resisted sled pulling and pushing has received considerable attention in team sport athletes [18][19][20][21]98]. Resisted sprint training methods likely facilitate improvements in net antero-posterior GRF capabilities [94,96,99], subsequently generating greater net antero-posterior impulse [18][19][20]100]. Kinematically, resisted sprinting has been shown to increase SL and forward trunk lean (improve position to orient antero-posterior GRF's) during un-resisted sprint accelerations [94][95][96]99]. ...
This thesis is based on a series of publications that were conducted with the aim of improving the assessment and development of sprint performance in junior AF players. Specifically, the objectives of the thesis were to examine the underlying FVP characteristics of maximum sprint performance through cross-sectional analysis across competition levels, maturation status, and draft outcome. Additionally, a longitudinal analysis explored the natural development of sprint performance and the influence of biological maturation. Finally, a longitudinal training intervention examined the effect of a sprint-specific training mesocycle on sprint performance and FVP characteristics. The specific aims of the thesis were to:
1. To establish the diagnostic ability of sprint times and sprint kinetic and kinematic characteristics in junior AF players.
2. Cross-sectionally explore the differences in sprint performance and sprint kinetics and kinematics in junior AF players through competition levels within the AFL player development pathway.
3. Longitudinally examine the natural development and influence of biological maturation on sprint performance and sprint kinetics and kinematics in junior AF players.
4. To assess the effectiveness of a sprint-specific training mesocycle on sprint performance and sprint kinetics and kinematics in junior AF players.
... Working at a given %BM can lead to a large variability between athletes in the amount they are slowed down during RSS. Alternatively, current research used load that is causing a reduction in maximum velocity (Vdec) when compared to unresisted sprinting [31,38,47,48]. This makes comparison of research very challenging. ...
In this study, we assessed the acute kinematic effects of different sled load conditions (unloaded and at 10%, 20%, 30% decrement from maximum velocity (Vdec)) in different sporting populations. It is well-known that an athlete’s kinematics change with increasing sled load. However, to our knowledge, the relationship between the different loads in resisted sled sprinting (RSS) and kinematic characteristics is unknown. Thirty-three athletes (sprinters n = 10; team sport athletes n = 23) performed a familiarization session (day 1), and 12 sprints at different loads (day 2) over a distance of 40 m. Sprint time and average velocity were measured. Sagittal-plane high-speed video data was recorded for early acceleration and maximum velocity phase and joint angles computed. Loading introduced significant changes to hip, knee, ankle, and trunk angle for touch-down and toe-off for the acceleration and maximum velocity phase (p < 0.05). Knee, hip, and ankle angles became more flexed with increasing load for all groups and trunk lean increased linearly with increasing loading conditions. The results of this study provide coaches with important information that may influence how RSS is employed as a training tool to improve sprint performance for acceleration and maximal velocity running and that prescription may not change based on sporting population, as there were only minimal differences observed between groups. The trunk lean increase was related to the heavy loads and appeared to prevent athletes to reach mechanics that were truly reflective of maximum velocity sprinting. Lighter loads seem to be more adequate to not provoke changes in maxV kinematics. However, heavy loading extended the distance over which it is possible to train acceleration.
... Resisted sprints (i.e., loaded sleds) were shown to increase both stride length and frequency and lead to an acute increase in forward trunk lean (improved position to generate horizontal impulse) during sprints < 20 m in team sport athletes and university students [182][183][184][185]. In contrast, assisted methods demonstrated increased stride length and decreased stride frequency in track athletes [33,44], whereas reduced ground contact times were reported in football code athletes [101]. ...
Background
Within the football codes, medium-distance (i.e., > 20 m and ≤ 40 m) and long-distance (i.e., > 40 m) sprint performance and maximum velocity sprinting are important capacities for success. Despite this, no research has identified the most effective training methods for enhancing medium- to long-distance sprint outcomes.
Objectives
This systematic review with meta-analysis aimed to (1) analyse the ability of different methods to enhance medium- to long-distance sprint performance outcomes (0–30 m, 0 to > 30 m, and the maximum sprinting velocity phase [ V max ]) within football code athletes and (2) identify how moderator variables (i.e., football code, sex, age, playing standard, phase of season) affected the training response.
Methods
We conducted a systematic search of electronic databases and performed a random-effects meta-analysis (within-group changes and pairwise between-group differences) to establish standardised mean differences (SMDs) with 95% confidence intervals and 95% prediction intervals. This identified the magnitude and direction of the individual training effects of intervention subgroups (sport only; primary, secondary, tertiary, and combined training methods) on medium- to long-distance sprint performance while considering moderator variables.
Results
In total, 60 studies met the inclusion criteria (26 with a sport-only control group), totalling 111 intervention groups and 1500 athletes. The within-group changes design reported significant performance improvements (small–moderate) between pre- and post-training for the combined, secondary (0–30 and 0 to > 30 m), and tertiary training methods (0–30 m). A significant moderate improvement was found in the V max phase performance only for tertiary training methods, with no significant effect found for sport only or primary training methods. The pairwise between-group differences design (experimental vs. control) reported favourable performance improvements (large SMD) for the combined (0 to > 30 m), primary ( V max phase), secondary (0–30 m), and tertiary methods (all outcomes) when compared with the sport-only control groups. Subgroup analysis showed that the significant differences between the meta-analysis designs consistently demonstrated a larger effect in the pairwise between-group differences than the within-group change. No individual training mode was found to be the most effective. Subgroup analysis identified that football code, age, and phase of season moderated the overall magnitude of training effects.
Conclusions
This review provides the first systematic review and meta-analysis of all sprint performance development methods exclusively in football code athletes. Secondary, tertiary, and combined training methods appeared to improve medium-long sprint performance of football code athletes. Tertiary training methods should be implemented to enhance V max phase performance. Nether sport-only nor primary training methods appeared to enhance medium to long sprint performance. Performance changes may be attributed to either adaptations specific to the acceleration or V max phases, or both, but not exclusively V max . Regardless of the population characteristics, sprint performance can be enhanced by increasing either the magnitude or the orientation of force an athlete can generate in the sprinting action, or both.
Trial Registration
OSF registration https://osf.io/kshqn/ .
... Among the mechanical determinants, sprint running performance is predominantly dependent on P max , V 0 , and D RF (Morin et al., 2011. Sprint-specific exercises, such as sled pushing (Cahill et al., 2020) and sled towing (Kawamori et al., 2014), have been used to improve these capacities. It has been suggested that training loads could be optimized for superior results based on an individual's FVP profile (Morin and Samozino, 2016). ...
This study aimed to assess the within- and between-session reliability of the KiSprint system for determining force-velocity-power (FVP) profiling during sprint running. Thirty (23 males, 7 females; 18.7 ± 2.6 years;) young high-level sprinters performed maximal effort sprints in two sessions separated by one week. Split times (5, 10, 20 and 30 m), which were recorded with a laser distance meter (a component of the KiSprint system), were used to determine the horizontal FVP profile using the Samozino’s field-based method. This method assesses the FVP relationships through estimates of the step-averaged ground reaction forces in sagittal plane during sprint acceleration using only anthropometric and spatiotemporal (split times) data. We also calculated the maximal theoretical power, force and velocity capabilities and the slope of the FV relationship, the maximal ratio of horizontal-to-resultant force (RF), and the decrease in the RF (DRF). Overall, the results showed moderate or good to excellent within- and between-session reliability for all variables (ICC > 0.75; CV < 10 %), with the exception of FV slope and DRF that showed low relative reliability (ICC = 0.47-0.48 within session, 0.31-0.33 between-session) and unacceptable between-session absolute reliability values (CV = 10.9-11.1 %). Future studies are needed to optimize the protocol in order to maximize the reliability of the FVP variables, especially when practitioners are interested in the FV slope and DRF. In summary, our results question the utility of the sprint-based FVP profiling for individualized training prescription, since the reliability of the FV slope and D RF variables is highly questionable.
... or 15.0-29.9%V dec ) and very heavy (.30%BM and .30.0% V dec ) RSS load training (7,9,12,14,(19)(20)(21)(22). Recent systematic reviews have suggested that training with light RSS loads produces greater improvements during higher velocity sprint phases, whereas heavy-to-very heavy RSS loads produce greater improvements in the acceleration phase of sprinting (1,23). ...
The acute physiological and perceptual responses to a single session of resisted sled sprint (RSS) training are largely unexplored, nor have differences, if any, between male and female athletes been compared. Team field sport athletes (n 5 27; male/female, 15/12; 21.1 6 2.7 years) were assessed for Maximal Resisted Sled Load (MRSL) from which light (L-RSS, 30%MRSL) and heavy (H-RSS, 80%MRSL) sled loads were prescribed. On separate occasions in random order, 2 training sessions of 12 3 20 m RSS repetitions at either L-or H-RSS were performed, and assessments of physiological and perceptual responses were performed before (PRE), during, after (POST) and 24 hours after (+24 hours POST) each session. Compared to unresisted sprints, velocity decrements of 7.5 6 2.2 and 22.7 6 8.1% were produced by L-RSS and H-RSS, respectively. Heart rate, blood lactate, and ratings of perceived exertion were higher in H-RSS compared to L-RSS. Decrements in 20 m sprint and countermovement jump performance observed at POST had returned to PRE values at +24 hours POST. Except for a higher heart rate (;7-12 b·min 21) in females during the respective sessions, responses to Land H-RSS were generally similar between males and females. A single session of heavy RSS training is more demanding than light RSS training when matched for sprint number and distance, but measures of lower limb power and sprint performance return to pre-training levels within 24 hours regardless of sled load. Males and females respond similarly to a single session of RSS training when individualized, relative intensity sled loads are prescribed.
... Sled towing is a popular training method in adult populations [12,23,34] and has been demonstrated to improve acceleration, maximum velocity and its underlying mechanisms (e.g., maximal net horizontal ground reaction force, [29]). Lighter loads are reported to improve maximum velocity capabilities [17,24] while heavier loads target acceleration [20]. More recently, the use of heavier loadings that cause a velocity loss of 50% [12], is believed to target training conditions that produce maximal power output (optimal force and optimal velocity, [11]) to enhance performance [10,19,42]. ...
Purpose
Sled towing has been shown to be an effective method to enhance the physical qualities in youth athletes. The aim of this study was to evaluate the impact of a 6-week sled towing intervention on muscular strength, speed and power in elite youth soccer players of differing maturity status.
Method
Seventy-three male elite youth soccer players aged 12–18 years (Pre-Peak Height Velocity [PHV] n = 25; Circa-PHV n = 24; Post-PHV n = 24) from one professional soccer academy participated in this study. Sprint assessments (10 m and 30 m), countermovement jump and isometric mid-thigh pull were undertaken before (T1) and after (T2) a 6-week intervention. The training intervention consisted of 6 weeks (2 × per week, 10 sprints over 20 m distance) of resisted sled towing (linear progression 10%–30% of body mass) during the competitive season. Bayesian regression models analysed differences between T1 and T2 within each maturity group.
Results
There were minimal changes in strength, speed and power ( P = 0.35–0.80) for each maturity group across the 6-week intervention. Where there were changes with greater certainty, they are unlikely to represent real effect due to higher regression to the mean (RTM).
Conclusion
It appears that a 6-week sled towing training programme with loadings of 10%–30% body mass only maintains physical qualities in elite youth soccer players pre-, circa-, and post-PHV. Further research is required to determine the effectiveness of this training method in long-term athletic development programmes.
... One such method is the utilisation of resisted towing (RST) devices. [2][3][4][5] RST devices predominantly provide a concentric overload to the musculoskeletal system by overloading horizontal force production during a sprint. [6][7][8] RST devices are often used by strength and conditioning coaches as an adjunct to gym-based resistance training. ...
Horizontal eccentric towing (HET) is a novel modality that delivers an eccentric overload to the musculature as an athlete attempts to move forward in a sprint stance whilst being pulled backwards. A device, called the HET, has been developed to automate this movement. Similar to a winch retracting an anchor on a boat, the HET device pulls an athlete that is tethered inwards and the athlete must resist this motion in a maximal manner, whilst maintaining a sprint stance. The HET device provides an isokinetic training modality by towing athletes inwards at a constant velocity. The HET device is operated by an electric 10 kW AC synchronous servo gearmotor. The motor is controlled by a variable speed drive (VSD) and programmable logic controller (PLC), which allow for accurate speed, position and torque control. A touchscreen PC runs the user interface displaying real-time force and speed measures. The HET device can produce a maximum towing force of 2.8 kN at ground velocities of up to 3.58 m/s. There is a separate safety PLC that triggers a safety-rated brake system when the E-stop buttons are pushed. This is paramount for athlete safety. In this technical note, the components used in the construction of the HET device will be detailed and insights into a novel stimulus will be offered, as well as a guide to develop and automate similar eccentric movements.
... Morin et al. (2017) showed that greater sled load (20%-120% body mass) increased maximal horizontal force production and mechanical effectiveness (i.e. more horizontally applied force), suggesting increased trunk lean may be a positive change in acceleration kinematics. Existing studies (Kawamori et al., 2014a, 2014b, Weyand et al., 2000 have demonstrated that this may transfer back into normal sprinting. During maximal velocity sprinting however, the body should be relatively upright, with the overall GRF oriented more vertically, to overcome the effects of gravity and so maintain maximum velocity. ...
The purpose of this study was to identify the kinematic characteristics of resisted sled sprinting under different loading conditions (0%, 10%, 20% and 30% velocity decrement (Vdec)) and in different sporting populations. Thirty-three healthy athletes (Sprinters n=10; Invasion team sport athletes n=23) were recruited and completed 3 days of testing. Kinematics were captured with high-speed cameras and processed using Dartfish Software. Loads of 20% and 30% Vdec resulted in a significant increase in trunk lean relative to unloaded sprinting, during both acceleration and maximum velocity phases, with no difference between groups (sprint & team sport athletes). This increase in trunk lean with load (20% and 30% Vdec) appeared to prevent athletes transitioning into upright maximum velocity mechanics, and therefore extended the distance of the acceleration phase. The trunk lean increase was related to the heavy loads and athletes were not able to reach mechanics that were truly reflective of maximum velocity (maxV) sprinting. However, heavy loading extended the distance over which it is possible to train acceleration.
... It is also important to note (and compare) the magnitude of relative increases in sprint velocity observed in the current study. Using this novel velocity-based model, it was found a 5.5% of decrease in 10-m sprint time for G10, who performed a total sprint distance of, on average, 675 m (380-880 m) across 10 training sessions, which is substantially lower than the training volume prescribed in previous studies which already reported similar increases in sprint performance (i.e., ;1,400 m during 12 sessions with ;13% BM in rugby players; and ;850 m during 16 sessions with ;45% BM in physically active men) (17,21). These similar improvements in sprint performance should be viewed with caution because of the differences in sample characteristics (i.e., soccer players vs. rugby players and physically active men). ...
This study investigated the effects of a 11-week moderate-to-heavy sled training intervention with different magnitudes of velocity loss on sprint and jump performance, mechanical muscle function, and body composition in professional soccer players. Seventeen players (age 25.8±4.3 years; height 180.0±8.6 cm; weight 77.7±9.7 kg) were randomly
allocated into two groups, based on different magnitudes of velocity loss: 10% of velocity decrease (G10, n=8) and 20% of velocity decrease (G20, n=9). The velocity-based sled
training consisted of 20m resisted sprints with a progressive loading increase from 45% to 65% of body-mass throughout the intervention. Pre- and post-intervention sprint and jump performance, hamstring and quadriceps peak torque and isometric rate of torque development, and lower-limb lean mass measured by dual X-ray absorptiometry were assessed and compared. Two-way repeated measures analysis of variance revealed a significant time-effect for decreases in 10m and 20m sprint times (p=0.018 and p=0.033, respectively), but without a time-group interaction. The G10 showed greater beneficial effects than G20 for both 10m (- 5.5±3.3%, magnitude-based inference [MBI]: possibly versus -1.7±5.9%, MBI: possibly trivial) and 20m (-2.5±2.1%, MBI: possibly versus -1.4±3.7%, MBI: likely trivial) sprint times. Moreover, there was a significant time effect for CMJ height and quadriceps isometric peak torque, which decreased significantly after training (p=0.019 and p=0.010, respectively), with no within-group effect of time versus group interaction for these respective outcomes. The novel velocity-based sled model proposed here, especially under lower magnitudes of velocity loss, was able to significantly improve linear sprint performance in professional soccer players.
The resisted method can provide an effective way to improve sprinting in both the acceleration and maximal velocity phases. However, substantial discrepancies exist in the literature regarding the influence of the athletes’ training status and the prescription of the load to be used in relation to the specific components of the desired sprint performance and its phases. The aim of this study was to carry out a systematic review of the research that analyzes the effects of the application of a sprint overload in rugby players, as well as to establish the results obtained in relation to the percentage of the load applied. For this purpose, the guidelines provided in the PRISMA Declaration were followed, and a search was conducted in five databases: PubMed, Web of Science, PsycInfo, Scopus, and SPORTDiscus. After screening, a total of 16 reports were included that met the proposed eligibility criteria. The results yielded information based on the effect of the application of an overload on the following aspects: (1) adaptation to training; (2) acute post-activation potentiation effect; and (3) acute effect and its influence on running kinematics and kinetics. It can be concluded that in order to work on weighted sprint training, the percentage of load to be used must be taken into account, as this percentage will determine to a large extent the effect that will be produced when it is applied.
The aim of the meta-analysis was to determine the acute effects of resisted (RST), assisted (AST), and unresisted (UST) sprint training on sprint performance and to identify the optimal training protocol. A computerized search was conducted in five databases, resulting in the inclusion of 23 studies and 395 participants. The findings indicated that RST acutely improved sprint performance (effect size [ES] -0.20; p < 0.05), while UST (ES = -0.03) and AST (ES = -0.18) did not produce significant improvements (p > 0.05). Subgroup analyses revealed that RST load as a percentage of body mass (%BM) showed the greatest improvement with heavy loads (50-75% BM, ES = -0.40) compared to light (0-19% BM, ES = -0.22), moderate (20-49% BM, ES = -0.21), and very heavy (>75% BM, ES = 0.10) loads. Further analyses indicated that sled pushing (ES = -0.60) was more effective than sled pulling (ES = -0.34) under heavy load RST conditions. Nonlinear meta-regression results demonstrated that sprint performance improvement exhibited an inverted-U relationship with RST load. Additionally, heavy load RST and moderate load AST did not disrupt subsequent sprinting technique. In conclusion, only RST acutely improved subsequent sprint performance, whereas AST and UST did not. For optimal results with RST, it is recommended to use one set of heavy loads (50-75% BM) for sled pushing over a distance of 15-20 meters, followed by a rest period of 4-8 minutes before performing 0-30 meters of UST.
Objective
To investigate the impact of post-activation potentiation (PAP) induced by resisted sled sprint at different loads on the subsequent 30 m ice push sled performance of Chinese skeleton athletes, and to identify the resisted sled sprint load that most effectively enhances PAP for Chinese skeleton athletes.
Methods
Seven elite athletes from the Chinese skeleton team participated in four tests with more than 48 h intervals. During the tests, on the first test, athletes completed a 40 min standard warm-up, rested for 6 min, and then performed a 30 m test. On the second, third, and fourth test, athletes completed the standard warm-up, then performed 20 m sprints with resisted sled (RS) at 75%, 50%, and 25% of body mass (BM), respectively, rested for 6 min, and then performed the 30 m test.
Results
No significant differences were found in morning pulse, blood urea, and creatine kinase levels among four tests. The percentage of maximum heart rate (%HRmax) within different intensity ranges showed no significant differences among four tests. However, significant differences were observed in ice push sled performance among four tests (No BMRS: 5.08 ± 0.27; 25% BMRS: 5.05 ± 0.29; 50% BMRS: 5.02 ± 0.27; 75% BMRS: 5.04 ± 0.28). Post hoc analyses revealed that the 50% BMRS test had faster speed compared to the no resistance ( p < 0.05), the 25% BMRS ( p < 0.05), and the 75% BMRS ( p < 0.05) tests. Additionally, the 75% BMRS test had faster speed than the no resistance test ( p < 0.05).
Conclusion
A 20 m sprint with 50% BMRS effectively enhances the PAP effect in skeleton athletes, improving their ice push sled performance. Coaches can incorporate this resisted sled sprint in athletes’ training routines for performance enhancement in both daily training and pre-competition preparations.
Background: Sprinting speed as a derivative of lower-body power is considered to be the most vital component of physical ability of the players. Traditional training methods fail to improve sprinting speed of the experienced players up to a certain limit that demands newer training means for further development of speed. Hypergravity Training (HT) has been identified as such a new type of training that was used by few researchers for the improvement of sprinting speed and power of the experienced rugby and soccer players. But it has still not been implemented on the cricketers for the development of sprinting speed. Objective: Therefore, the current randomized control trial was directed to assess the development of sprinting speed of the cricketers through the implementation of HT in comparison with the Normalgravity Training (NT) condition. Method: The present study was a quasi-experimental research work. One hundred and five (N=105) state cricketers were selected as subjects. The participants were split into three equal groups (n=35 each) viz. i) Normalgravity Training Group (NGTG), ii) Hypergravity Training Group (HGTG) iii) Control Group (CG). NGTG HGTG groups underwent the same exercise protocol for the periods of twelve weeks in normal hypergravity conditions respectively whereas CG was free from the training intervention. Sprinting speed of the cricketers was measured by a 30m run test. ANCOVA preceded by Tukey’s LSD test were performed for data analysis. Statistical significance was examined at p.05 level. Results: Significant F-value (F=61.122; p 0.001) was observed. Sprinting speed of both training groups (NGTG HGTG) improved significantly (Mean Diff=1.28 0.86; Critical Diff =0.41) in comparison to the CG. HGTG also differed significantly (Mean Diff =0.42; Critical Diff =0.41) when compared with NGTG in sprinting speed. Conclusions: The sprinting speed of HGTG improved better than NGTG. Therefore, HT is found as an effective training means for developing sprinting speed.
Speed, power and acceleration ability are important components for most of the summer sports, such as athletics, football, rugby, handball and basketball. Our analytical review compiles and systematizes by physical criteria (conditions change and influence of external or internal factors) the long-term studies of experts on the use of non-traditional means and methods in sports training to improve the ability to speed up and develop the maximum speed and power of running. The non-traditional methods include conjugate influence used in sprinters’ training, which correspond or slightly exceed the basic kinematic and dynamic criteria of the basic competitive exercise. Research analysis confirmed the efficiency of conjugate influence exercises and their impact on kinematic spatial and temporal parameters and on the dynamic parameters of the running stride reflecting the interaction of internal and external forces. Studies have also confirmed a positive immediate and long-term post-training trace effect. The survey research confirms that the use of traditional sprint training along with non-traditional means and methods enables the athlete to avoid the formation of a speed barrier, to improve acceleration, maximum speed, and running power.
Background:
Different sized parachutes may alter applied resistance during parachute towing (PT), changing results of resisted sprint training interventions. Thus, it was hypothesized that there may be significant net anteroposterior ground reaction force and impulse differences due to parachute size towed.
Methods:
Fifteen male sprinters completed control and PT sprints over a 50 m force platform system. Estimated aerodynamic drag, ground reaction forces and kinematic differences during the maximum speed phase were compared between control (no parachute) and PT trials with small (0.39 m2), medium (0.54 m2) and large (0.72 m2) parachutes, using One-way ANOVA (significance set at P < .050) with Tukey's HSD post hoc (Critical Q value = 3.746) tests.
Results:
No significant (P > .050) step length, step frequency, propulsive mean force, vertical mean force or vertical impulse differences between trials. There was a significant anteroposterior impulse difference (P < .001, Q = 4.574) between small and medium PT, but no differences between medium and large PT. Compared to the control trial, all PT trials increased anteroposterior net mean force (P < .001), anteroposterior net impulse (P <.001), and propulsive impulse (P < .001). However, only PT with the large parachute significantly reduced running speed (P < .050, Q = 3.792), braking mean force (P < .050, Q = 4.130) and braking impulse (P < .001, Q = 5.987), compared to the control trial.
Conclusions:
A large parachute may be most effective for PT (compared to control trial) to overload the body during the maximum speed phase in a single session.
Sprinting speed plays a crucial role in many sports, and it is considered a fundamental motor skill. Various training methods can be used to improve sprinting speed. Researchers have shown strength and plyometric training (PT) to be effective in improving sprinting speed. However, most studies have reviewed the effects of strength and PT on sprinting performance in adults and young males. There is a paucity of research that has reviewed the effects of strength and PT on sprinting performance in young females across maturation (pre-peak height, mid-peak height, and post-peak height velocity: peak height velocity student athletes, age 10–16 years). Moreover, no previous review has provided practical strength and PT strategies for young female student-athletes that acknowledge important factors such as growth, forces, and enjoyment. Therefore, this review highlights the importance of progressive strength and PT on sprinting performance in young females and provides practical training programs that can be implemented within a school curriculum. More specifically, this review provides exercise progressions in strength and power training for an eight-week training block that can be easily implemented by strength and conditioning coaches within a school term.
Background
Sprint performance is an essential skill to target within soccer, which can be likely achieved with a variety of methods, including different on-field training options. One such method could be heavy resisted sprint training. However, the effects of such overload on sprint performance and the related kinetic changes are unknown in a professional setting. Another unknown factor is whether violating kinematic specificity via heavy resistance will lead to changes in unloaded sprinting kinematics. We investigated whether heavy resisted sled training (HS) affects sprint performance, kinetics, sagittal plane kinematics, and spatiotemporal parameters in professional male soccer players.
Methods
After familiarization, a nine-week training protocol and a two-week taper was completed with sprint performance and force-velocity (FV) profiles compared before and after. Out of the two recruited homogenous soccer teams ( N = 32, age: 24.1 ± 5.1 years: height: 180 ± 10 cm; body-mass: 76.7 ± 7.7 kg, 30-m split-time: 4.63 ± 0.13 s), one was used as a control group continuing training as normal with no systematic acceleration training (CON, N = 13), while the intervention team was matched into two HS subgroups based on their sprint performance. Subgroup one trained with a resistance that induced a 60% velocity decrement from maximal velocity ( N = 10, HS60%) and subgroup two used a 50% velocity decrement resistance ( N = 9, HS50%) based on individual load-velocity profiles.
Results
Both heavy resistance subgroups improved significantly all 10–30-m split times ( p < 0.05, d = − 1.25; −0.62). Post-hoc analysis showed that HS50% improved significantly more compared to CON in 0–10-m split-time ( d = 1.03) and peak power ( d = 1.16). Initial maximal theoretical horizontal force capacity (F0) and sprint FV-sprint profile properties showed a significant moderate relationship with F0 adaptation potential ( p < 0.05). No significant differences in sprinting kinematics or spatiotemporal variables were observed that remained under the between-session minimal detectable change.
Conclusion
With appropriate coaching, heavy resisted sprint training could be one pragmatic option to assist improvements in sprint performance without adverse changes in sprinting kinematics in professional soccer players. Assessing each player’s initial individual sprint FV-profile may assist in predicting adaptation potential. More studies are needed that compare heavy resisted sprinting in randomized conditions.
Guerra, MA Jr, Caldas, LA, Souza, HL, Tallis, J, Duncan, MJ, and Guimarães-Ferreira, L. The effects of physical fitness on postactivation potentiation in professional soccer athletes. J Strength Cond Res XX(X): 000-000, 2020-To investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response.
Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field-sport athletes. Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of body mass. Stride length was significantly reduced by similar to10 and similar to24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. In addition, sled towing increased ground contact time, trunk lean, and hip flexion. Upper-body results showed an increase in shoulder range of motion with added resistance. The heavier load generally resulted in a greater disruption to normal acceleration kinematics compared with the lighter load. The lighter load is likely best for use in a training program.
Acceleration performance is important for field sport athletes that require a high level of repeat sprint ability. Although acceleration is widely trained for, there is little evidence outlining which kinematic factors delineate between good and poor acceleration. The aim of this study was to investigate the kinematic differences between individuals with fast and slow acceleration. Twenty field sport athletes were tested for sprint ability over the first three steps of a 15m sprint. Subjects were filmed at high speed to determine a range of lower body kinematic measures. For data analysis, subjects were then divided into relatively fast (n = 10) and slow (n = 10) groups based on their horizontal velocity. Groups were then compared across kinematic measures, including stride length and frequency, to determine whether they accounted for observed differences in sprint velocity. The results showed the fast group had significantly lower (~11-13%) left and right foot contact times (p < .05), and an increased stride frequency (~9%), as compared to the slow group. Knee extension was also significantly different between groups (p < .05). There was no difference found in stride length. It was concluded that those subjects who are relatively fast in early acceleration achieve this through reduced ground contact times resulting in an improved stride frequency. Training for improved acceleration should be directed towards using coaching instructions and drills that specifically train such movement adaptations.
We transposed the concept of effectiveness of force application used in pedaling mechanics to calculate the ratio of forces (RF) during sprint running and tested the hypothesis that field sprint performance was related to the technical ability to produce high amounts of net positive horizontal force. This ability represents how effectively the total force developed by the lower limbs is applied onto the ground, despite increasing speed during the acceleration phase.
Twelve physically active male subjects (including two sprinters) performed 8-s sprints on a recently validated instrumented treadmill, and a 100-m sprint on an athletics track. Mean vertical (FV), net horizontal (FH), and total (FTot) ground reaction forces measured at each step during the acceleration allowed computation of the RF as FH/FTot and an index of force application technique (DRF) as the slope of the RF-speed linear relationship from the start until top speed. Correlations were tested between these mechanical variables and field sprint performance variables measured by radar: mean and top 100-m speeds and 4-s distance.
Significant (r > 0.731; P < 0.01) correlations were obtained between DRF and 100-m performance (mean and top speeds; 4-s distance). Further, FH was significantly correlated (P < 0.05) to field sprint performance, but FTot and FV were not.
Force application technique is a determinant factor of field 100-m sprint performance, which is not the case for the amount of total force subjects are able to apply onto the ground. It seems that the orientation of the total force applied onto the supporting ground during sprint acceleration is more important to performance than its amount.
Various studies have demonstrated that resistance sprint (RS) training can produce significant changes in running speed and running kinematics. The longer-term training adaptations after RS training remain unclear. The purpose of this study was to investigate whether an RS training intervention would enhance the running speed and dynamic strength measures in male rugby players. Fifteen male rugby players aged 20.5 (+/- 2.8) years who were proficient in resisted sledge training took part in the study. The subjects were randomly assigned to control or RS groups. The RS group performed two sessions per week of RS training for 6 weeks, and the control group did no RS training. Pre- and postintervention tests were carried out for 30-m sprint, drop, squat, and rebound jumps on a force sledge system. A laser measurement device was used to obtain velocities and distance measures during all running trials. The results show a statistically significant decrease in time to 5 m for the 30-m sprint for the RS group (p = 0.02). The squat jump and drop jump variables also showed significant increases in starting strength (p = 0.004) and height jumped (p = 0.018) for the RS group from pre- to post-testing sessions. The results suggest that it may be beneficial to employ an RS training intervention with the aim of increasing initial acceleration from a static start for sprinting.
The aim of this study was to compare sprint performance over 10 and 20 m when participants ran while towing resistances, weighing between 0 and 30% of body mass. The sample of 33 participants consisted of male rugby and soccer players (age 21.1 +/- 1.8 years, body mass 83.6 +/- 13.1 kg, height 1.82 +/- 0.1 m; mean +/- s). Each participant performed two sets of seven sprints over 20 m using a Latin rectangular design. The times were recorded at 10 and 20 m using electronic speed gates. The sprints of 13 players were video-recorded to allow calculation of stride length and frequency. For both sprints, a quadratic relationship was observed between sprint time and resistance as sprint time increased from 2.94 s to 3.80 s from 0 to 30% resistance. This relationship was statistically significant but considered not to be meaningful for performance because, over the range of resistances used in this study, the quadratic model was never more than 1% (in terms of sprint time) from the linear model. As resistance increased, the stride length shortened, with mean values of 1.63 +/- 0.13 m at 0% body mass and 1.33 +/- 0.13 m at 30% of body mass. There was no significant change in stride frequency with increasing resistance. The results show that in general there is an increase in sprint time with an increase in resistance. No particular resistance in the range tested (0 - 30%) can be recommended for practice.
The purpose of the present study was to examine the effects of resisted (RS) and un-resisted (US) sprint training programs on acceleration and maximum speed performance.
Twenty-two male students (age 20.1+/-1.9 y, height 1.78+/-7 cm, and weight 73+/-2 kg) completed RS (n=11) or US (n=11) sprint training programs. The RS group followed a sprint-training program with 5 kg sled pulling and the US group followed a similar sprint-training program without sled pulling. The training program consisted of 4x20 m and 4x50 m maximal runs, and was applied 3 times/week for 8 weeks. Before and after the training programs the subjects performed a 50 m run and the running velocity of 0(-1)0 m, 10(-2)0 m, 20-40 m and 40-50 m was measured. In addition, stride length and stride frequency were evaluated at the 3(rd) stride in acceleration phase and between 42-47 m in maximum speed phase.
The RS improved running velocity in the run sections 0(-1)0 m and 0(-2)0 m, while in US group the running velocity in all run sections in acceleration phase remained unchanged (p>0.05). In contrast, RS training had no effect on running velocity in maximum speed phase, whereas US improved running velocity in 20-40 m, 40-50 m, and 20-50 m run sections (p<0.05). Stride rate increased only after RS in acceleration phase (+7.1+/-2.9%; p<0.05), whereas stride length increased only after US in maximum speed phase (+5.5+/-2.5%; p<0.05).
Sprint training with 5 kg sled pulling for 8 weeks improves acceleration performance (0(-2)0), while un-resisted sprint training improves performance in maximum speed phase (20-40) in non-elite athletes. It appears that each phase of sprint run demands a specific training approach.
Field-based team sports, such as soccer, rugby and hockey are popular worldwide. There have been many studies that have investigated the physiology of these sports, especially soccer. However, some fitness components of these field-based team sports are poorly understood. In particular, repeated-sprint ability (RSA) is one area that has received relatively little research attention until recent times. Historically, it has been difficult to investigate the nature of RSA, because of the unpredictability of player movements performed during field-based team sports. However, with improvements in technology, time-motion analysis has allowed researchers to document the detailed movement patterns of team-sport athletes. Studies that have published time-motion analysis during competition, in general, have reported the mean distance and duration of sprints during field-based team sports to be between 10-20 m and 2-3 seconds, respectively. Unfortunately, the vast majority of these studies have not reported the specific movement patterns of RSA, which is proposed as an important fitness component of team sports. Furthermore, there have been few studies that have investigated the physiological requirements of one-off, short-duration sprinting and repeated sprints (<10 seconds duration) that is specific to field-based team sports. This review examines the limited data concerning the metabolic changes occurring during this type of exercise, such as energy system contribution, adenosine triphosphate depletion and resynthesis, phosphocreatine degradation and resynthesis, glycolysis and glycogenolysis, and purine nucleotide loss. Assessment of RSA, as a training and research tool, is also discussed.
Acceleration is an important factor for success in team-sport athletes. The purpose of this investigation was to compare the reliability of 10-m sprint times when using different starting techniques. Junior male rugby players (n = 15) were tested for speed over 10 m on 2 different testing sessions. Three trials of 3 different starting techniques (standing, foot, and thumb starts) were assessed. Despite large differences in the time taken to perform 10-m sprints from different starts, there was minimal difference in the typical error (approximately 0.02 seconds, or <1%) between the 3 different starts. There was a small, 0.02 +/- 0.02 second, decrease (p = 0.05) in sprint time between sessions for the foot start. For all starting techniques, the magnitude of error (typical error) was greater than the smallest worthwhile change (<0.01 second), indicating that acceleration over 10 m measured by photocells only has a marginal chance of reliably detecting a change of sufficient magnitude to be worthwhile in practical terms. However, by accounting for the smallest worthwhile change and typical error, it is possible to establish the probability an individual has had a worthwhile change in sprint performance. Coaching and sports-science practitioners can use a variety of sprint-start techniques shown to have small typical errors (<1%); however, the results from the different starting technique are not interchangeable.
Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field-sport athletes. Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of body mass. Stride length was significantly reduced by approximately 10 and approximately 24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. In addition, sled towing increased ground contact time, trunk lean, and hip flexion. Upper-body results showed an increase in shoulder range of motion with added resistance. The heavier load generally resulted in a greater disruption to normal acceleration kinematics compared with the lighter load. The lighter load is likely best for use in a training program.
Acceleration is a significant feature of game-deciding situations in the various codes of football. However little is known about the acceleration characteristics of football players, the effects of acceleration training, or the effectiveness of different training modalities. This study examined the effects of resisted sprint (RS) training (weighted sled towing) on acceleration performance (0-15 m), leg power (countermovement jump [CMJ], 5-bound test [5BT], and 50-cm drop jump [50DJ]), gait (foot contact time, stride length, stride frequency, step length, and flight time), and joint (shoulder, elbow, hip, and knee) kinematics in men (N = 30) currently playing soccer, rugby union, or Australian football. Gait and kinematic measurements were derived from the first and second strides of an acceleration effort. Participants were randomly assigned to 1 of 3 treatment conditions: (a) 8-week sprint training of two 1-h sessions x wk(-1) plus RS training (RS group, n = 10), (b) 8-week nonresisted sprint training program of two 1-h sessions x wk(-1) (NRS group, n = 10), or (c) control (n = 10). The results indicated that an 8-week RS training program (a) significantly improves acceleration and leg power (CMJ and 5BT) performance but is no more effective than an 8-week NRS training program, (b) significantly improves reactive strength (50DJ), and (c) has minimal impact on gait and upper- and lower-body kinematics during acceleration performance compared to an 8-week NRS training program. These findings suggest that RS training will not adversely affect acceleration kinematics and gait. Although apparently no more effective than NRS training, this training modality provides an overload stimulus to acceleration mechanics and recruitment of the hip and knee extensors, resulting in greater application of horizontal power.
The purpose of this study was to investigate the relation between running speed and a number of common strength and power tests, in absolute terms and relative to body mass. Twenty professional rugby league players were assessed for 10- and 40-m running speed, maximum strength in a 3 repetition maximum (RM) squat and 3RM power clean from the hang, and leg power. Power was assessed by the Plyometric Power System (PPS) during barbell jump squats with loads of 40, 60, 80, and 100 kg. The results indicated that, while 10- and 40-m sprint performances are highly related (r = 0.72, p <= 0.05), there still remains considerable variation in the factors that contribute to performance over each sprint distance. Although no absolute strength or power score was significantly related to either sprint performance, almost all the scores relative to body mass were significantly related to sprint performance. For the 10-m sprint, the significant relations ranged from r = -0.52 to r = -0.61 (p <= 0.05). For the 40-m sprint, the significant relations ranged from r = -0.65 to r = -0.76 (p <= 0.05). On the basis of this research, professional rugby players may need to be trained differently to a certain extent for 10- and 40-m sprint capabilities, as the longer distances appear more reliant on stretch-shortening cycle performance.
(C) 1999 National Strength and Conditioning Association
Large horizontal acceleration in short-sprints is a critical performance parameter for many team-sport athletes. It is often stated that producing large horizontal impulse at each ground contact is essential for high short sprint performance, but the optimal pattern of horizontal and vertical impulses is not well understood, especially when the sprints are initiated from a standing start. This study was an investigation of the relationships between ground reaction impulses and sprint acceleration performance from a standing start in team-sport athletes. Thirty physically active young men with team-sport background performed 10-m sprint from a standing start, while sprint time and ground reaction forces were recorded during the first ground contact and at 8 m from the start. Associations between sprint time and ground reaction impulses (normalized to body mass) were determined by a Pearson's correlation coefficient (r) analysis. The 10-m sprint time was significantly (P < 0.01) correlated with net horizontal impulse (r = -0.52) and propulsive impulse (r = -0.66) measured at 8 m from the start. No significant correlations were found between sprint time and impulses recorded during the first ground contact after the start. These results suggest that applying ground reaction impulse in a more horizontal direction is important for sprint acceleration from a standing start. This is consistent with the hypothesis of training to increase net horizontal impulse production using sled towing or using elastic resistance devices, which needs to be validated by future longitudinal training studies.
First, the biomechanical differences between the acceleration phase and the maximum velocity phase of sprinting are considered. Second, research on the various resisted sprinting techniques is examined, linking these techniques to the biomechanics of the acceleration phase. Some suggestions are made regarding the application of these findings to the training of athletes.
The purpose of this study was to determine the longitudinal effects of weighted sled (WS) and weighted vest (WV) sprint training on maximum velocity sprint performance and kinematics. Twenty male collegiate lacrosse players were randomly assigned to a WS group (n = 7) towing 10% body mass, a WV group (n = 6) loaded with 18.5% body mass, or an unresisted (UR) active control group (n = 7). All subjects completed 13 training sessions over 7 weeks. Pre- and post-test measures of sprint time and average velocity across the distance interval of 18.3 to 54.9 m were used to assess sprint performance, whereas high-speed video (300 Hz) and motion-analysis software were used to analyze stride length, stride rate, ground contact time, and flight time. A 3 × 2 repeated measures analysis of variance was performed for each dependent variable and revealed no significant between-group differences for any of the sprint performance or kinematic stride cycle measures. Effect size statistics suggested small improvements in 18.3- to 54.9-m sprint time and average velocity for the UR group but only trivial improvements for the WS and WV groups. With regard to sprint performance, the results indicate that WS and WV training had no beneficial effect compared with UR training. In fact, for the loads used by WS and WV in this study, UR training may actually be superior for improving sprint performance in the 18.3- to 54.9-m interval.
An excessive load in resisted sprint training can produce changes in running patterns. Therefore, load control is essential to ensure the specificity of these training methods. The most common way to control it is through the percentage of velocity lost in relation to maximum velocity. The present paper describes a study that aimed to establish the load for sprint training with sled towing. The study developed a regression equation for calculating the load in the maximum velocity phase. The calculation was done with 26 athletes from the Spanish and French national levels on a synthetic track surface and with spikes. The regression equation obtained was % body mass = (-0.8674 x % velocity) + 87.99. The equation, although specific for type of surface used and sled towing characteristics, is useful in establishing the optimal load for acceleration and maximum velocity training with sled towing.
Harrison, AJ, and Bourke, G. The effect of resisted sprint training on speed and strength performance in male rugby players. J Strength Cond Res 23(1): xxx-xxx, 2009-Various studies have demonstrated that resistance sprint (RS) training can produce significant changes in running speed and running kinematics. The longer-term training adaptations after RS training remain unclear. The purpose of this study was to investigate whether an RS training intervention would enhance the running speed and dynamic strength measures in male rugby players. Fifteen male rugby players aged 20.5 (+/- 2.8) years who were proficient in resisted sledge training took part in the study. The subjects were randomly assigned to control or RS groups. The RS group performed two sessions per week of RS training for 6 weeks, and the control group did no RS training. Pre- and postintervention tests were carried out for 30-m sprint, drop, squat, and rebound jumps on a force sledge system. A laser measurement device was used to obtain velocities and distance measures during all running trials. The results show a statistically significant decrease in time to 5 m for the 30-m sprint for the RS group (p = 0.02). The squat jump and drop jump variables also showed significant increases in starting strength (p = 0.004) and height jumped (p = 0.018) for the RS group from pre- to posttesting sessions. The results suggest that it may be beneficial to employ an RS training intervention with the aim of increasing initial acceleration from a static start for sprinting.
Seven male subjects performed 15 x 40m sprints, on three occasions, with rest periods of either 120 s (R120), 60 s (R60) or 30 s (R30) between each sprint. Sprint times were recorded with four photo cells placed at 0, 15, 30 and 40 m. The performance data indicated that whereas running speed over the last 10 m of each sprint decreased in all three protocols (after 11 sprints in R120, 7 sprints in R60 and 3 sprints in R30), performance during the initial acceleration period from 0-15 m was only affected with the shortest rest periods increasing from (mean +/- SEM) 2.58 +/- .03 (sprint 1) to 2.78 +/- .04 s (spring 15) (p < .05). Post-exercise blood lactate concentration was not significantly different in R120 (12.1 +/- 1.3 mmol.l-1) and R60 (13.9 +/- 1.2 mmol.l-1), but a higher concentration was found in R30 (17.2 +/- .7 mmol.l-1) (p < .05). After 6 sprints there was no significant difference in blood lactate concentration with the different recovery durations, however, there were significant differences in sprint times at this point, suggesting that blood lactate is a poor predictor of performance during this type of exercise. Although the work bouts could be classified primarily as anaerobic exercise, oxygen uptake measured during rest periods increased to 52, 57 and 66% of maximum oxygen uptake in R120, R60 and R30, respectively. Evidence of adenine nucleotide degradation was provided by plasma hypoxanthine and uric acid concentrations elevated post-exercise in all three protocols. Post-exercise uric acid concentration was not significantly affected by recovery duration.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this study is to analyze the effect of high-resistance (HR) and high-velocity (HV) training on the different phases of 100-m sprint performance. Two training groups (HR and HV) were compared with two control groups (RUN and PAS). The HR (N = 22) and HV group (N = 21) trained 3 d.wk-1 for 9 wk: two strength training sessions (HR or HV) and one running session. There was a run control group (RUN, N = 12) that also participated in the running sessions (1 d.wk-1) and a passive control group (PAS, N = 11). Running speed over a 100-m sprint was recorded every 2 m. By means of a principal component analysis on all speed variables, three phases were distinguished: initial acceleration (0-10 m), building-up running speed to a maximum (10-36 m), and maintaining maximum speed in the second part of the run (36-100 m). HV training resulted in improved initial acceleration (P < 0.05 compared with RUN, PAS, and HR), a higher maximum speed (P < 0.05 compared with PAS), and a decreased speed endurance (P < 0.05 compared to RUN and PAS). The HV group improved significantly in total 100 m time (P < 0.05 compared with the RUN and PAS groups). The HR program resulted in an improved initial acceleration phase (P < 0.05 compared with PAS).
Today, it is generally accepted that sprint performance, like endurance performance, can improve considerably with training. Strength training, especially, plays a key role in this process. Sprint performance will be viewed multidimensionally as an initial acceleration phase (0 to 10 m), a phase of maximum running speed (36 to 100 m) and a transition phase in between. Immediately following the start action, the powerful extensions of the hip, knee and ankle joints are the main accelerators of body mass. However, the hamstrings, the m. adductor magnus and the m. gluteus maximus are considered to make the most important contribution in producing the highest levels of speed. Different training methods are proposed to improve the power output of these muscles. Some of them aim for hypertrophy and others for specific adaptations of the nervous system. This includes general (hypertrophy and neuronal activation), velocity specific (speed-strength) and movement specific (sprint associated exercises) strength training. In developing training strategies, the coach has to keep in mind that strength, power and speed are inherently related to one another, because they are all the output of the same functional systems. As heavy resistance training results in a fibre type IIb into fibre type IIa conversion, the coach has to aim for an optimal balance between sprint specific and nonspecific training components. To achieve this they must take into consideration the specific strength training demands of each individual, based on performance capacity in each specific phase of the sprint.
The purpose of this study was to determine whether a flexibility training program, a weight training program, and the combination of both would affect running speed when used as supplementary training programs to the conventional method of training sprinters. One hundred and forty-five subjects, randomly assigned to one of five training groups, were tested for flexibility, leg strength, and running speed before and after an 8-week training period. Results showed that both weight training and flexibility training, as supplements to sprint training, increased running speed significantly more than an unsupplemented sprint training program.
The appropriateness of normalizing data, as one method to reduce the effects of a covariate on a dependent variable, should be evaluated. Using ratio, 0.67-nonlinear, and fitted normalizations, the aim of this study was to investigate the relationship between ground reaction force variables and body mass (BM). Ground reaction forces were recorded for 40 female subjects running at 3.7 +/- 0.18 m x s(-1) (mass = 58 +/- 6 kg). The explained variance for mass to forces (peak-impact-vertical = 70%; propulsive-vertical = 27%; braking = 40%) was reduced to <0.1% for mass to ratio normalized forces (i.e., forces/BM1) with statistically significantly different power exponents (p < 0.05). The smaller covariate effect of mass on loading rate variables of 2-16% was better removed through fitted normalization (e.g., vertical-instantaneous-loading rate/ BM(0.69+/-0.93); +/-95% CI) with nonlinear power exponents ranging from 0.51 to 1.13. Generally, these were similar to 0.67 as predicted through dimensionality theory, but, owing to the large confidence intervals, these power exponents were not statistically significantly different from absolute or ratio normalized data (p > 0.05). Further work is warranted to identify the appropriate method to normalize loading rates either to mass or to another covariate. Ratio normalization of forces to mass, as predicted through Newtonian mechanics, is recommended for comparing subjects of different masses.
The effect of different starting stances from a standing position on short sprint times and the subsequent variability in times was investigated in this study. A dual-beam timing light system was used to measure 5- and 10-m times for 3 different standing starts commonly found in the sporting environment: parallel (feet parallel to the start line), split (lead left foot on start line, right leg back), and false (initial parallel start, right leg drops back to split start when movement initiated). The parallel start was found to be significantly (alpha < 0.05) slower than the other 2 stances for both the 5- ( approximately 8.3%) and the 10-m (approximately 5.9%) distances. Within the trial, variation of the different starting stances was equally consistent; however, there was less variability for the 10-m distance (CV = 1.16-1.67%) than the 5-m distance (CV = 1.43-2.15%) for each start for both men and women. The split and false start seem to offer the best option as a movement strategy for minimizing short-distance sprint times. However, the benefits of these 2 starts are less clear if total movement time is the variable of interest.
Influence of strength training on sprint running perfor mance. Current findings and implications for training
- C Delecluse
Delecluse, C. Influence of strength training on sprint running perfor
mance. Current findings and implications for training. Sports Med 24:
147–156, 1997.
The pros and cons of using resisted and assisted training methods with high school sprinters: parachutes, tubing, and towing.
- Jakalski
Jakalski, K. The pros and cons of using resisted and assisted training
methods with high school sprinters: parachutes, tubing, and towing.
Track Coach 144: 4585-4589, 4612, 1998.
The effects of resisted sprint training on acceleration performance and kinematics in soccer, rugby union, and Australian football players.
- Spinks