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This study aimed to compare the effects of 6-week resisted sprint (RST) versus conventional (unresisted) sprint training (CG) on sprint time, change of direction (COD) speed, repeated sprint ability (RSA) and jump performance (countermovement jump (CMJ) and standing long jump (SLJ)) in male young tennis players. Twenty players (age: 16.5 ± 0.3 years; body mass: 72.2 ± 5.5 kg; body height: 180.6 ± 4.6 cm) were randomly assigned to one of the two groups: RST (n = 10) and CG (n = 10). The training program was similar for both groups consisting of acceleration and deceleration exercises at short distances (3-4 m), and speed and agility drills. The RST group used weighted vests or elastic cords during the exercises. After 6 weeks of intervention, both training regimes resulted in small-to-moderate improvements in acceleration and sprint ability (5, 10, 20 m), SLJ and CMJ performances, COD pivoting on both, the non-dominant (moderate effect) and the dominant (small effect) foot, and the percentage of decrement (small effects) during a RSA test. Between-group comparisons showed that the SLJ (Δ = 2.0%) and 5 m sprint time (Δ = 1.1%) improved more in the RST group compared with the CG group. This study showed that 6 weeks of RST or unresisted training are time-efficient training regimes for physical improvements in young male tennis players.
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Ahead of print DOI: 10.2478/hukin-2019-0142
Effects of resisted vs. conventional sprint training on physical fitness
in young elite tennis players
Manuel Moya-Ramon1, Fabio Yuzo Nakamura2, Anderson Santiago Teixeira3,
Urs Granacher4, Francisco Javier Santos-Rosa5, David Sanz-Rivas6,
Jaime Fernandez-Fernandez6,7
1 Department of Sports Sciences, Miguel Hernandez University, Elche, Spain;
2 Department of Medicine and Aging Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy; The College
of Healthcare Sciences, James Cook University, Townsville, Australia; Associate Graduate Program in Physical
Education UPE/UFPB, João Pessoa, PB, Brazil;
3 Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianópolis - SC, Brazil; Research
Group for Development of Football and Futsal, Sports Center, Federal University of Santa Catarina, Florianópolis -
SC, Brazil;
4 Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Potsdam,
5 Faculty of Sport, Pablo de Olavide University, Seville, Spain
6 Spanish Tennis Federation, Madrid, Spain.
7 Department of Physical Activity and Sport Sciences, Universidad de León, Spain.
Corresponding Author:
Jaime Fernandez-Fernandez, Phd
Department of Physical Activity and Sports Sciences.
Universidad de León.
Campus de Vegazana s/n, 24071 – Spain; Phone: (0034)987293026
This study aimed to compare the effects of 6-week resisted sprint (RST) versus conventional
(unresisted) sprint training (CG) on sprint time, change of direction (COD) speed, repeated sprint ability
(RSA) and jump performance (countermovement jump (CMJ) and standing long jump (SLJ)) in male young
tennis players. Twenty players (age: 16.5 ± 0.3 years; body mass: 72.2 ± 5.5 kg; body height: 180.6 ± 4.6 cm)
were randomly assigned to one of the two groups: RST (n = 10) and CG (n = 10). The training program was
similar for both groups consisting of acceleration and deceleration exercises at short distances (3-4 m), and
speed and agility drills. The RST group used weighted vests or elastic cords during the exercises. After 6
weeks of intervention, both training regimes resulted in small-to-moderate improvements in acceleration
and sprint ability (5, 10, 20 m), SLJ and CMJ performances, COD pivoting on both, the non-dominant
(moderate effect) and the dominant (small effect) foot, and the percentage of decrement (small effects)
during a RSA test. Between-group comparisons showed that the SLJ (Δ = 2.0%) and 5 m sprint time (Δ =
1.1%) improved more in the RST group compared with the CG group. This study showed that 6 weeks of
RST or unresisted training are time-efficient training regimes for physical improvements in young male
tennis players.
Keywords: Young athletes, sprint performance, tennis, power.
Tennis match play is characterized by intermittent whole body efforts with short (2-10 s) bouts of
high-intensity exercise during rallies followed by short (10-20 s) recovery bouts between rallies and a longer
rest period between games (60-90 s). Overall, this results in an average match time of ~1.5 h (Fernandez-
Fernandez et al., 2009; Kovacs, 2006, 2007). After serving the ball with a velocity of 180-200 km·h-1, a tennis
player needs to accelerate not only in a straight line, but also laterally and multi-directionally. In other
words, rapid stop and go movements together with quick change of directions (CODs) constitute major
performance determinants in tennis (Fernandez-Fernandez et al., 2014). Consequently, the development and
design of training regimes that have the potential to enhance these sport-specific fitness qualities are of
significant interest to tennis coaches as well as strength and conditioning specialists.
There is evidence in the literature that different training protocols are effective in improving jump,
sprint and COD performances (Loturco et al., 2017). Moreover, it has been reported that training-induced
enhancements in muscle strength and power translate into sprint and COD performances (Cormie et al.,
2011). Of note, specific strength exercises have been implemented in sprint training routines. This is also
known as resisted sprint training (RST) (Hrysomallis, 2012; Petrakos et al., 2016). Previous research has
shown that RST improves maximum strength and sprint performances (Cottle et al., 2014; Martínez-Valencia
et al., 2015). However, findings in the literature are controversial. A recent systematic review showed no
additional effects of RST on linear sprint speed compared with conventional or unresisted sprint training
regimes (Petrakos et al., 2016). The observed discrepancies in previous research are most likely due to the
large methodological heterogeneity with regard to the included resistive sprint devices. While some studies
used weighted sleds or weighted vests (Carlos-Vivas et al., 2018; Clark et al., 2010), others used parachutes
or elastic cables (Gil et al., 2018; Loturco et al., 2017). In addition, ineffective overload principles were
implemented in the respective training regimes (Gil et al., 2018). Despite this controversy in the literature,
there are few studies with tennis players that illustrate the positive effects of conventional sprint (i.e.,
repeated sprint) training on physical fitness (i.e., linear sprint speed, jump and COD performances) in junior
elite (Fernandez-Fernandez et al., 2015) or moderately trained tennis players (Fernandez-Fernandez et al.,
2012). However, to the best of our knowledge, no previous study has analyzed the effects of RST compared
with unresisted sprint training on physical fitness in young tennis players.
Therefore, the aim of this study was to contrast the effects of RST versus conventional (i.e.,
unresisted) linear sprint training on linear sprint and COD performances as well as lower-limb power (i.e.,
countermovement jump and standing long jump) in young tennis players. Based on the study of Gil et al.
(2018), we hypothesized that RST would be more effective in improving specific physical fitness compared
with the unresisted sprint training in tennis players.
Twenty competitive male junior tennis players (mean ± SD; age: 16.5 ± 0.3 years; body mass: 72.2 ±
5.5 kg; body height: 180.6 ± 4.6 cm) with an international ranking between 150 and 300 (International Tennis
Federation ranking) participated in this study. Players were divided into a resisted training group (RST; n =
10; mean ± SD; age: 16.7 ± 0.1 years; body mass: 72.0 ± 5.2 kg; body height: 181.6 ± 4.8 cm) and a conventional
group (CG; n = 10; mean ± SD; age: 16.4 ± 0.3 years; body mass: 71.1 ± 7.2 kg; body height: 179.9 ± 4.4 cm).
The mean training background of the players was 9.0 ± 2.6 years, which focused on tennis-specific training
(i.e., technical and tactical skills), aerobic and anaerobic training (i.e., on- and off-court exercises), and basic
strength training. They were all free of cardiovascular and pulmonary diseases and were not taking any
medication. Written informed consent was obtained from players and their parents/legal representatives.
The study was approved by the institutional Research Ethics Committee (Coaches Education and Research
Area, Spanish Tennis Federation (RFET); reference: RFET2019-RS1), and conformed to the recommendations
of the latest version of the Declaration of Helsinki.
Sprint Test
Running speed was evaluated using the 20-m linear sprint test from a standing start with 5 and 10 m
split times (Time It; Eleiko Sport, Halmstad, Sweden). Each sprint was initiated from an individually chosen
standing position, 50 cm behind the photocell gate, which started a digital timer. Each player performed 3
maximal 20-m sprints, separated by at least 2 min of passive recovery. The best performance was recorded
for further analysis. The intraclass correlation coefficient (ICC) for the time of this sprint test was 0.87.
Modified 5-0-5 Agility Test (COD test)
The abilities of athletes to perform a single, rapid 180° change of direction over a 5 m distance was
measured using a modified version (stationary start) of the 5-0-5 agility test (Gallo-Salazar et al., 2017).
Players started in a standing position with their preferred foot behind the starting line. Thereafter they
accelerated in a forward direction without a racket at maximal effort. One trial pivoting on both the
dominant (505 DOM) and the non-dominant limb (505 ND) was completed and the best time recorded to the
nearest 0.01 s (Time It; Eleiko Sport, Halmstad, Sweden). Two minutes of rest were allowed between trials.
The ICC of this test was 0.92.
Vertical Jump Test
The vertical jump is a common action in many sports. Biomechanically it is similar to game-related
dynamic and vertical movements (Girard et al., 2005; Markovic et al., 2004). Thus, it is important to include
some type of vertical-jump assessment to evaluate explosive power in tennis. Accordingly, a
countermovement jump (CMJ) without an arm swing was performed on a contact platform (Ergojump®,
Finland). Each player performed 3 maximal CMJs interspersed with 45 s of passive recovery, and the best
trial with highest jump height was used for further analysis (Markovic et al., 2004). The ICC of the jump
height for this test was 0.92.
Standing Long Jump (SLJ) Test
For the SLJ, players stood behind a starting line with feet shoulder width and placed together. They
pushed off vigorously and jumped forward for maximal distance. The distance was measured from the take-
off line to the point where the back of the heel nearest to the take-off line landed on the ground. The best (in
cm) out of 2 trials was used for subsequent statistical analysis (Castro-Piñero et al., 2010). The ICC of the
jump distance for this test was 0.78.
Repeated-Sprint Ability (RSA) Shuttle Test
To measure RSA, we used a test consisting of ten 21-m shuttle sprints (i.e., 5 m + 11 m + 5 m), which
was designed to measure both repeated sprint and COD abilities. The test was conducted in accordance with
a previous study (Fernandez-Fernandez et al., 2012). Players stood with their racket in a frontal position in
the middle of the baseline focusing the net. Upon an acoustic signal, players turned sideway and ran to the
prescribed backhand (left) or the forehand (right) corner. Players were instructed to run forward in a straight
line and turn around (180º) as their feet touched the line of the turning point and their racket a cone on the
line. After having touched the first cone with the racket, athletes returned to the opposite side of the court by
running forward. There they touched the second cone with the racket, turned around and ran to the starting
position. After 15 s of passive recovery, players started again. Each shuttle sprint time was measured using a
photocell system (Time It; Eleiko Sport, Halmstad, Sweden). The mean time and the percent decrement score
during the RSA test were calculated. Each player completed a preliminary single shuttle sprint test, which
was used as a criterion score for the subsequent shuttle sprint test. After the first preliminary single shuttle
sprint, players rested for 5 min before the start of the RSA test. If performance during the first RSA trial was
worse than the criterion score (i.e., 2.5% longer time to complete the test), the test was immediately
terminated and athletes were asked to repeat the RSA test at maximum effort after a 5-min rest period
(Fernandez-Fernandez et al., 2012; Spencer et al., 2005). ICC values for best RSA time (RSAbest), mean RSA
time (RSAmean), and percentage of decrement (%Dec) were 0.81, 0.73 and 0.49, respectively.
Design and procedures
The 20 tennis players involved in the study were matched and allocated into a RST and a
conventional group (CG) and were tested before and after a 6-week specific conditioning program. The
intervention took place at the beginning of the summer competition season (April to May). Single and
double tennis matches were played every weekend during the experimental period. After appropriate
familiarization (i.e., completion of a full testing session 1 week before pretests), the physical fitness tests were
completed 1 week before and after the training period. During the intervention period, both groups, RST and
CG, performed 2 training sessions per week in addition to their regular training regimes for 6 consecutive
weeks. Sessions were separated by 48 h to allow sufficient recovery time. RST and CG sprint training was
conducted at the beginning of the training session after a short standardized 8 to 10-min dynamic warm-up
and prior to the tennis-specific session.
To reduce the interference of uncontrolled variables, all participants were instructed to maintain
their habitual lifestyle and normal dietary intake before and during the study. Players were told not to
exercise on the day before a test and to consume their last (caffeine-free) meal at least 2 hours before the
scheduled test time. Physical fitness tests were conducted at the same time of day during pre- and post-tests.
Participants had to complete at least 85% of the training sessions and all tests were included in the final data
Specifically, the training program consisted of a combination of acceleration and deceleration
movements at short distances (3-4 m) and speed/agility drills (8-10 s) without any additional load/resistance
(CG) or using weighted vests (WVs) (Kettler, Germany) and elastics cords (ECs) (SKLZ, Durham, USA)
(RST). Due to the complexity of supervising the tennis-specific training program, coaches organized weekly
meetings to assign similar tennis training loads to both RST and CG groups (i.e., number of exercises,
technical/tactical aims). Both groups completed the same training (consisting of forward, backward and
multidirectional sprints, with 1 to 6 changes of directions [COD]), interspersed with 25 s of active recovery
between repetitions and 2-3 min rest intervals between sets) (Table 1). The only difference between the two
interventions was that the RST group performed the exercises requiring more CODs with a weighted vest
that corresponded to 10-15% of each individual’s body mass (a moderate load according to a prior study;
Petrakos et al., 2016). The RST group additionally used a medium resistance elastic cord which was fixated
around the athletes’ waist offering resistance during exercises requiring less CODs. Following a previous
study (Gil et al., 2018), the overload in the latter training mode reduced sprinting performance to the nearest
of 10% in comparison to the unresisted condition (Hrysomallis, 2012). As inappropriate overload may alter
movement technique, and consequently the magnitude of chronic adaptations, the additional overload was
kept constant throughout the experimental period. Both groups, RST and CG, followed their normal tennis
training (4-5 × week), in addition to 2 self-regulated low- to moderate-intensity injury prevention (e.g., core
training, shoulder and hip strengthening, and flexibility) sessions.
Statistical Analyses
Data are presented as means and standard deviations (± SD) or ± 90% confidence intervals (± 90%
CI). First, training-induced adaptations were compared using a two-way repeated measure ANOVA with
one between factor (RST vs. CG) and one within factor (pre-training vs. post-training). When a significant F
value was detected, Bonferroni post hoc procedures were used. The significance level was set at p 0.05.
These analyzes were carried out using the SPSS (SPSS 17.0 version, Chicago, Illinois, USA). Second, data
were also analyzed for practical significance using magnitude-based inferences (MBI) (Hopkins et al., 2009).
To examine the effects of the type of intervention (RST vs. CG) on RSA, change of direction speed, and
proxies of lower-limb power, differences between groups (RST vs. CG) and over time (pre-training vs. post-
training) were calculated. The smallest worthwhile change (SWC) was calculated (0.2 × SD) and 90% CIs
were determined. Quantitative chances of beneficial/higher or harmful/lower effects were assessed
qualitatively as follows: 25 to 75%, possibly; 75 to 95%, likely; 95 to 99%, very likely; and >99%, almost
certain. If the chance of having beneficial/higher or harmful/lower performances was both >5%, the true
difference was assessed as unclear. In addition, effect sizes (Cohen’s d) of changes in physical fitness were
calculated (Hopkins et al., 2009). Threshold values for Cohen’s d effect size (ES) were 0.20, 0.60, 1.20, 2.0 and
4.0 for small, moderate, large, very large and extremely large effects, respectively. Pearson correlation
coefficients (r) were used to determine the relationships between changes in SLJ and CMJ performances with
changes in sprint running performance. The magnitude of relationships was assessed according to the
following thresholds: 0.1, trivial; >0.1-0.3, small; >0.3-0.5, moderate; >0.5-0.7, large; >0.7-0-9, very large; and
>0.9-1.0, almost perfect. Practical inferences of the correlation coefficients were also considered (Hopkins,
Table 2 shows the raw data, relative changes, and qualitative outcomes derived from MBI analyses
for all physical fitness measurements.
Two-way repeated measures ANOVA
There was no interaction (time vs. training group) or main effect for group (p > 0.05) for all physical
performance variables. After the training intervention, except for RSAbest (F = 3.083; p = 0.096), a significant
main time effect was found for all the other performance outcomes. The following analyzed variables
significantly improved from pre- to post-training period in both RST and CG groups: 5 m (F = 33.492; p <
0.001), 10 m (F = 18.871; p < 0.001) and 20 m (F = 24.308; p < 0.001) sprint times, 505 ND (F = 18.705; p < 0.001)
and 505 DOM (F = 12.627; p = 0.002), SLJ height (F = 56.091; p < 0.001), CMJ height (F = 38.764; p < 0.001),
RSAmean (F = 10.860; p = 0.004) and %Dec (F = 7.846; p = 0.012).
Magnitude-based inferences approach
Baseline between-group differences were rated as unclear for all performance outcomes. Following
training, sprint times improved in both groups and all split times, with decreases in 5 m (ES ± 90% CI,
qualitative descriptor for RST: -0.66 ± 0.31, very likely; for CG: -0.67 ± 0.28, very likely), 10 m (for RST: -0.32 ±
0.20, likely; for CG: -0.77 ± 0.39, very likely), and 20 m sprint times (for RST: -0.46 ± 0.33, likely; for CG: -0.57 ±
0.20, almost certainly).
An enhanced performance was observed after both training regimes for the ability to change
directions quickly, with meaningful changes in 505 ND (RST: -0.60 ± 0.43, likely; CG: -0.64 ± 0.31, very likely)
and 505 DOM (RST: -0.41 ± 0.28, likely; CG: -0.42 ± 0.29, likely). Post training, improvements in all measures of
jump performance were found for RST and CG groups. Performance enhancements were observed for the
SLJ (RST: 0.63 ± 0.24, almost certainly; CG: 0.69 ± 0.22, almost certainly) and the CMJ (RST: 0.39 ± 0.19, very
likely; CG: 0.62 ± 0.24, almost certainly). Training-induced changes for RSA performance were detected for
%Dec (RST: 0.43 ± 0.39, likely; CG: 0.24 ± 0.21, possibly), RSAbest (RST: -0.11 ± 0.22, possibly trivial; CG: -0.08 ±
0.09, very likely trivial), and RSAmean (RST: -0.23 ± 0.20, possibly; CG: -0.15 ± 0.10, likely trivial).
Figure 1 shows between-group changes over time. Compared to the CG group, improvements in the
SLJ (ES ± 90% CI = 0.31 ± 0.34) and 5 m sprint time (ES ± 90% CI = 0.29 ± 0.43) were possibly (chance of a
greater real effect > 60%) larger in the RST group. The magnitudes of differences were rated as small. There
were no substantial differences (unclear effects) for the changes in %Dec, RSAbest, 505 ND, 505 DOM, 10 and
20 m sprint times between both training groups. Finally, between-group differences in the change of RSAmean
were likely trivial (ES ± 90% CI = -0.03 ± 0.20).
Figure 2 shows the relationship between physical fitness indices. Within-player correlations between
absolute changes in the SLJ and the CMJ with absolute changes in running sprint performances were
obtained when pooling the data of RST and CG groups. There were likely moderate correlations between
changes in the CMJ and the SLJ with some selected changes in 5 m, 10 m and 20 m sprint time.
Findings of this study revealed that both training regimes resulted in small-to-moderate
improvements in acceleration and sprint abilities (5, 10 and 20 m), horizontal and vertical jump
performances, COD pivoting on both, the non-dominant (moderate effect) and the dominant (small effect)
foot, and %Dec (small effects) during a RSA test, in male junior tennis players. Between-group comparisons
showed that the SLJ and 5 m sprint time improved more in the RST group compared with the CG group.
Overall, these findings partially confirm that RST induces larger physical fitness improvements compared to
unresisted sprint training.
To the best of our knowledge, there are no studies available that have compared the effects of
unresisted training with those of resisted sprint training in young tennis players. Of note, training-induced
changes in this study ranged from 1.2 to 3.2% for sprint performance, irrespective of the training regime.
This range is similar to findings from previous studies which examined the effects of RST using different
training equipment (i.e., elastic bands, weighted sleds, vests) (Alcaraz et al., 2018; Clark et al., 2010).
The observed improvements in both experimental groups can most likely be explained with
primarily neural adaptive processes (e.g., motoneuron excitability) (Ross et al., 2001) which might have
caused enhanced muscle force production and movement velocity (Perrey et al., 2010). With reference to
previous research, the use of weighted vests and elastic cords aims at eliciting greater vertical and horizontal
net ground reaction forces during speed or agility drills, respectively (Clark et al., 2010; Rey et al., 2017). In
this study, we could not find an additional effect of RST compared with CG possibly due to the low
resistance that was used in RST (Petrakos et al., 2016). According to Petrakos et al. (2016), moderate loads
with 10.0 to 19.9% of the individual body mass (10-15% in the present study) seem not to be sufficient to
produce extra effects compared with unresisted sprint training. Regarding the resistance offered by the
elastic cord, we allowed no more than 10% velocity reductions in the designed training drills in order to
preserve their biomechanical characteristics (e.g., stretch-shortening cycle participation) (Gil et al., 2018), but
at the same time induce greater lower-limb power and force production (Alcaraz et al., 2018). However, due
to the lack of control over the load applied in the exercises, it can be hypothesized that the tension generated
through the elastic cords cannot be kept constant during the entire exercise (Gil et al., 2018). This may have
resulted in a limited accuracy in overload control.
In spite of the lack of significant differences between training groups, meaningful differences
between RST and CG were observed for the 5 m sprint change. These results are in line with previous
research reporting that RST (i.e., using sled towing and weighted vests) was effective in improving kinetics
and kinematics during short bouts of accelerations (Alcaraz et al., 2018; Monte et al., 2017). A reason for this
difference between groups could be related to the greater increase in the capacity to produce anterior-
posterior force application during RST.
Since fitness demands in tennis include multiple accelerations, decelerations and COD performance,
the observed gains in the 5-0-5 test in both the RST (1.1% and 1.6% for the dominant and non-dominant
sides, respectively) and the CG group (1.2% and 1.5% for the dominant and non-dominant sides,
respectively) seem to be practically relevant for competitive performance. We are not aware of previous
studies that reported positive changes in COD after combining weighted vest and elastic cord training while
performing short sprints (combined with multiple COD). Otero-Esquina et al. (2017) reported gains in linear
and COD sprint when combining strength training exercises (i.e., full-back squat, leg curl on a flywheel
device, plyometrics) and sled towing in soccer players. The combination of elastic cords with weighted vests
impacted more on the COD pivoting on the non-dominant limb, in which a moderate effect was noticed,
compared to the small effect on the dominant limb. A possible explanation for this finding is that this limb
had lower initial ability to perform COD, and hence there was a better chance to improve this leg’s strength,
power and stiffness with adequate training stimuli.
Besides improving sprint ability, both unresisted and resisted sprint training resulted in increased
SLJ (RST: +5.3%; CG: +3.2%) and CMJ (RST: +5%; CG: +6.8%) performances. This is in agreement with the
notion that improved sprint performance is to a high degree related to enhancements in lower-limb muscle
power production in both vertical and horizontal directions (Loturco et al., 2018), inferred from jump height
and distance, respectively. In fact, the observed significant correlations between increases in SLJ and CMJ
performance and reduced sprint times from pre- to post-training confirm the neuro-mechanical relationships
between these qualities. Moreover, since there is a transfer of increment in the SLJ to acceleration
performance over short distances (e.g., 5 m) (Loturco et al., 2015), this may explain why the SLJ and
acceleration over 5 m improved more in the RST group compared with the CG group. It is apparent that
force and power production in the anterior-posterior axis were optimized by the use of additional (but light)
resistance during training drills performed by tennis players. However, unresisted sprint training was also
effective in enhancing vertical and horizontal jump performances, and this partly confirms the results from
other studies conducted with individual and team sports athletes (Fernandez-Fernandez et al., 2015; Gil et
al., 2018; Spinks et al., 2007).
Since training of competitive tennis players should focus on improving their ability to repeatedly
perform high-intensity efforts and to recover rapidly between bouts (Fernandez-Fernandez et al., 2012),
training strategies that aim to improve qualities such as RSA could be significant for tennis. The results of
our MBI-based approach revealed that only RST improved RSAmean (-1.3%; small effect size), although
between-group delta changes were not different. Previously, it was shown that futsal players displayed
greater RSA improvements in a group combining resistance training with loaded change of direction drills,
compared to a group that solely conducted resistance training and a control group (Torres-Torrelo et al.,
2018). Torres-Torrello et al. (2018) observed that improvements in RSAmean were accompanied with shorter
ground contact time during sprints, suggesting an increase in the rate of force development. Unfortunately,
we did not conduct kinematic sprint analysis to elucidate and confirm this finding. Both RST and CG
resulted in better %Dec during the RSA test, without any changes in RSAbest. However, the response of this
index to training should be viewed with caution (Bishop et al., 2011), since, for example, a detraining period
can impair RSAbest and artificially improve %Dec. Of note, in this study, tennis players of both groups
showed similar changes in %Dec, in the expected direction, given that they followed the respective training
regimes. However, due to the positive adaptation in RSAmean that was observed in RST only with the MBI
approach, it is advisable that strength and conditioning professionals adopt resisted short accelerations and
sprints in their routines to improve this performance relevant physical quality for tennis (Fernandez-
Fernandez et al., 2012).
In summary, both conventional (unresisted) and resisted sprint and COD training drills
implemented for 6 weeks in junior tennis players appeared to be effective in improving key physical fitness
components for youth tennis, such as acceleration speed, horizontal and vertical jump ability, change of
direction and repeated sprint ability. However, there were small, but meaningful advantages of performing
resisted drills to improve horizontal jump and 5-m acceleration, compared to unresisted sprint training
It is also important to highlight possible limitations of this study. The interpretation and application
of our data have to be done with caution as our findings are specific to a population of young male tennis
players. Regarding the applied training methods, it should be acknowledged that the use of elastic cords
does not allow to adequately follow the overload principle because the load cannot be kept constant.
Furthermore, and also related to the training equipment used here, there is evidence from recent studies to
suggest that heavier loads (i.e., inducing speed reduction > 10-15% established here) are needed to induce
performance improvements, in particular if the goal is to improve sprint performance over short distances
(Kawamori et al., 2014; Morin et al., 2017; Petrakos et al., 2016).
Conclusions and Practical Implications
Based on the present results, 6 weeks of RST or unresisted sprint training appear to represent a time-
efficient stimulus for physical fitness improvements in young male tennis players. Given the relatively low
training volume and the low cost of training equipment, this intervention seems to be practically relevant for
tennis coaches and athletes. RST and/or unresisted sprint training can easily be integrated two times per
week as part of the regular in-season training. Of note, it should always be conducted prior to a tennis
session (Fernandez-Fernandez et al., 2018). Since small differences can be very important when working
with elite athletes, the small advantages of RST over unresisted sprint training to improve horizontal jump
and 5-m acceleration may suggest that RST should be preferred over unresisted sprint training if the goal is
to improve sport-specific performance determinants in youth tennis.
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Table 1. Training program for both groups.
Week Sets
1 1 6 25 - *8 s drills; RSG: 3 exercises with WV (10%BM) and
3 with EC
2 2 5 25 2 *10 s drills; RSG: 5 exercises with WV (10%BM) and
5 with EC
3 2 5 25 2 *10 s drills; RSG: 5 exercises with WV (12%BM) and
5 with EC
4 2 6 30 3 *10 s drills; RSG: 2 x 3 exercises with WV (12%BM)
and 2 x 3 with EC
5 2 6 30 3 *10-12 s drills; RSG: 2 x 3 exercises with WV
(15%BM) and 2 x 3 with EC
6 2 8 35 4 *10-12 s drills; RSG: 2 x 4 exercises with WV
(15%BM) and 2 x 4 with EC
RST: Resisted sprint training group; * The unresisted training group performed the same drills, but with no
extra resistance added; WV: Weighted vest; EC: Elastic cords; BM: Body mass
Table 2. Descriptive statistics and within-group changes (with 90% confidence interval [CI]) in repeated sprint ability,
change of direction and proxies of muscle power after resisted (RST) and conventional (CG) sprint training interventions.
% Change (90%
(90% CI) B/T/H Descriptor
%DEC (%)
RST -3.7 ± 1.3 -3.1 ± 1.1* -16.92 (-1.28; 32.56) 0.43 (0.03; 0.82) 84/15/01 Likely
CG -3.8 ± 1.7 -3.4 ± 1.4* -11.63 (-1.30; -
21.96) 0.24 (0.03; 0.45) 62/38/00 Possibly
RSAmean (s)
RST 4.48 ± 0.24 4.42 ± 0.22* -1.30 (-2.43; -0.16) -0.23 (-0.44; -
0.03) 61/39/00 Possibly
CG 4.52 ± 0.33 4.47 ± 0.32* -1.12 (-1.85; -0.38) -0.15 (-0.24; -
0.05) 00/83/17 Likely Trivial
RSAbest (s) RST 4.32 ± 0.25 4.29 ± 0.21 -0.70 (-2.01; 0.63) -0.11 (-0.33; 0.10) 24/75/01 Possibly
CG 4.35 ± 0.34 4.32 ± 0.33 -0.70 (-1.41; 0.03) -0.08 (-0.17; 0.00) 00/98/02 Likely Trivial
505 ND
RST 3.02 ± 0.07 2.97 ± 0.06* -1.61 (-2.74; -0.47) -0.60 (-1.03; -
0.17) 94/06/00 Likely
CG 3.00 ± 0.07 2.95 ± 0.07* -1.49 (-2.22; -0.76) -0.64 (-0.95; -
0.32) 99/01/00 Very likely
505 DOM
RST 2.95 ± 0.07 2.92 ± 0.08* -1.09 (-1.84; -0.34) -0.41 (-0.69; -
0.13) 90/10/00 Likely
CG 2.93 ± 0.08 2.93 ± 0.08* -1.19 (-2.03; -0.36) -0.42 (-0.71; -
0.12) 89/11/00 Likely
SLJ (cm)
RST 233.3 ± 17.5 245.4 ± 15.4* 5.27 (3.25; 7.32) 0.63 (0.39; 0.86) 100/00/0
CG 232.0 ± 9.9 239.5 ± 11.4* 3.23 (2.19; 4.28) 0.69 (0.47; 0.91) 100/00/0
CMJ (cm)
RST 38.8 ± 4.3 40.6 ± 3.5* 4.97 (2.49; 7.52) 0.39 (0.20; 0.58) 95/05/00 Very Likely
CG 36.3 ± 3.5 38.7 ± 3.5* 6.76 (4.15; 9.44) 0.62 (0.39; 0.86) 100/00/0
20 m Sprint
RST 3.09 ± 0.12 3.09 ± 0.12* -1.92 (-3.28; -0.55) -0.46 (-0.78; -
0.13) 91/09/00 Likely
CG 3.12 ± 0.12 3.05 ± 0.11* -2.26 (-3.04; -1.48) -0.57 (-0.76; -
10 m Sprint
RST 1.80 ± 0.07 1.77 ± 0.05* -1.25 (-2.05; -0.45) -0.32 (-0.52; -
0.11) 84/16/00 Likely
CG 1.82 ± 0.04 1.78 ± 0.05* -1.79 (-2.70; -0.88) -0.77 (-1.16; -
0.38) 99/01/00 Very Likely
5 m Sprint (s)
RST 1.06 ± 0.05 1.02 ± 0.05* -3.15 (-4.56; -1.71) -0.66 (-0.97; -
0.36) 99/01/00 Very Likely
CG 1.07 ± 0.03 1.04 ± 0.03* -2.08 (-2.95; -1.20) -0.67 (-0.95; -
0.38) 99/01/00 Very Likely
%DEC: Percentage of decrement; RSAmean: Mean time of the repeated sprint ability (RSA) test; RSAbest: Best time of the RSA
test; ND: Non-Dominant side; DOM: Dominant side; SLJ: Standing long jump; CMJ: Countermovement jump; * Based on
two-way repeated measures ANOVA, the analysis indicates that there was a significant main effect of “time” (p < 0.05); B:
beneficial; T: trivial; H: harmful.
Figure 1.
Effects of
Conventional Sprint Training (CG) on repeated sprint ability, change of direction speed, standing long jump
(SLJ), countermovement (CMJ), and running sprint performances. Bars indicate uncertainty in the true mean
changes (with 90% confidence limits). Grey area represents the smallest worthwhile change.
Figure 2. Within-player correlations of the absolute changes (Δ) in standing long jump (SLJ) and
countermovement jump (CMJ) with absolute changes (Δ) in running sprint performances.
... In total, 13 intervention programs were utilized in the included studies ( Table 2). These interventions included resisted training (24), core training (21), a combination of highintensity intermittent rounds and tennis-specific training, tennisspecific exercises (19), plyometric training (18), a combination of explosive strength and repeated sprint training (17), neuromuscular warm-up (NWU) training, dynamic warm-up (DWU) training (25), neuromuscular training (NMT) prior to tennis-specific training, NMT post-tennis-specific training (20), various stretching exercises (22), high-intensity interval training (HIIT), and on-court tennis training (OTT) (23). The duration of the trials covered in the nine studies ranged from 4 to 8 weeks (mean 6.6 weeks). ...
... All of the studies were RCTs with a pre-post design. Four studies had an experimental (EG) and a control group (CG) (17,18,21,24), while only five studies included two experimental and no CGs (19,22,23,25). ...
... In the study conducted by Fernandez-Fernandez et al. (17), they observed a statistically significant (p < 0.05) improvement in speed (10 m sprint test) and a highly significant (p < 0.01) improvement in repeated sprint ability, but there were no significant changes in the sprint 20 and 30 m test (17). Moya-Ramon et al. (24) compared EG and CG using a resisted sprint training program. They concluded that while speed on the 5 m sprint time was considerably increasing (effect size 0.29), no significant difference was observed in the 10 m sprint time, 20 m sprint time, or repeated-sprint ability shuttle time (effect size −0.03). ...
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... Five studies have used novice athletes as their participants (16,20,26,41,67) with 5 studies also using subelite athletes (16,20,21,43,68). There was only a 1.79% difference between subelite and novice athlete times. ...
... Like the traditional 5-0-5 COD test, we cannot comment on the interaction between sex and sport as no research groups have reported male and female COD times in the same sport for the modified 5-0-5 COD test. Nevertheless, 6 out of the 9 studies that reported performance data have involved tennis athletes (16,17,21,34,41,43). This makes sense as the movement patterns of the modified 5-0-5 COD test are very similar to movements performed during a tennis match. ...
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... The best attempt of the 3 jumps carried out was used for further analyses. Reliability has provided acceptable levels in young athletes [29]. ...
... The best (RSAbest) and mean sprint times (RSAmean) were recorded as the performance criteria. The reliability of RSAbest and RSAmean has been described elsewhere [18,29]. ...
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Objective: To examine the association between phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) and components of physical performance in male youth soccer players. Design: Cross-sectional. Methods: Sixty-two players from two professional soccer academies were recruited. Electrical bioimpedance was used to obtain the PhA and BIVA. Body fat (BF) and lean soft tissue mass (LSTM) were measured by dual-energy X-ray absorptiometry. All players completed physical tests including the standing long jump (SLJ), Carminatti's test (peak speed at the end of the test, PST-CAR), 10 m and 30 m straight-line sprints, and repeated-sprint ability (RSA) test (RSAbest and RSAmean times). Results: Adjusting for chronological age, BF, and LSTM, multiple regression analysis outputs showed that PhA remained inversely related to RSAmean (β = -0.362; p < 0.001), RSAbest (β = -0.239; p = 0.020), 10 m (β = -0.379; p = 0.012), and 30 m (β = -0.438; p < 0.001) sprint times, while the association with PST-CAR and SLJ performance were statistically non-significant. In addition, BIVA showed that differences in confidence ellipses were found between athletes in the reference population and the study sample (p < 0.05). The tolerance ellipses indicated that the athletes in the present study had more total body water (TCW) and lower proportions of intracellular water (ICW) to extracellular water (ECW). The reference population had more TCW and ICW/ECW. Conclusions: Our results suggest that young soccer players with higher PhA values, indicating better cell integrity and functionality, have better performance in typical anaerobic running activities, such as sprinting speed and RSA performance, adjusted to age and body composition characteristics.
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Introduction The current challenge in tennis training in China is the integration with technology because, with the existing training methods, coaches and players pay little attention to strategies using a simple and retrograde tactical training method. Solutions need to be created to meet the development requirements of modern tennis. Objective This paper aims to analyze tennis players’ technical level, tactical characteristics, and training methods in sports competitions. Methods Eight male tennis players were randomly selected as research volunteers. The various tactics employed by the subjects under competition were observed. Based on the collected data, a mathematical-statistical analysis of the tennis players’ technical usage and training performance was prepared. Results The athletes in this study could use various offensive tactics during and after the experiment. The athletes have a strong offensive baseline and can use a combination of speed, spin, and positioning to restrict each other during the competition. However, there were significant differences in the players’ awareness of offensive tactics on defense (P<0.05). Conclusion Most athletes perform consistently and heterogeneously in stalemate tactics. A weakness noted was that most athletes are not showing good efficiency in scoring when stalemate presents opportunities. The results of this study can improve the scoring rate of tennis players. At the same time, this study's findings may strengthen tennis players’ ability to control the game during sports competitions. Level of evidence II; Therapeutic studies - investigation of treatment outcomes. Keywords: Tennis; Physical Education and Training; Athletes; Program, Training
... A review of the literature shows that the use of plyometric training in everyday tennis training significantly affects the ability to change direction; more precisely, better results are achieved in change of direction tests (T-test, 505 test) [5] and in the sidestep test [8]. The application of combined plyometric and tennis training also showed an improvement in speed, more precisely, a 20 m sprint [5] and 12 m sprint [6]. ...
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The purpose of this study is to investigate the effect of 6 weeks (conducted twice per week for a total of 12 sessions) of plyometric training with resistance bands on different neuromuscular characteristics among the sample of junior tennis players. Thirty junior tennis players between the ages of 12 and 14 years (age 13.5 ± 1.8 years; weight 51.3 ± 12.5 kg; height 162.7 ± 12.6 cm) were allocated to either the control group (standard in-season regimen) (CG; n = 15) or the experimental group, which received additional plyometric training with resistance bands (TG; n = 15). Pre- and post-tests included: anthropometric measures; 20 m sprint time (with 5, 10, and 20 m splits), squat jump (SQ Jump); vertical countermovement jump (CMJ); vertical countermovement jump with arm swing (CMJ_free arms); single leg (left) countermovement jump (CMJ_L); single leg (right) countermovement jump (CMJ_R); standing long jump (L_Jump); single leg (left) triple jump (SLTH-L); single leg (right) triple jump (SLTH-R); generic change of direction speed (CODS) (20Y test and T-test); reactive agility test (WS-S). After the training intervention, the TG showed significant (“p < 0.05”) improvements in CMJ (F = 7.90, p = 0.01), CMJ_L (F = 5.30, p = 0.03), CMJ_R (F = 11.45, p = 0.00), and SLTH-L (F = 4.49, p = 0.04) tests. No significant changes were observed in the CG after the training intervention. Our findings provide useful information for coaches to create a wide range of tennis-specific situations to develop a proper performance, especially for their player’s neuromuscular fitness.
... When the weight-bearing degree reaches the maximum, the body will mobilize some new muscles (groups) that did not work in the stable state to participate in the movement to overcome the unstable state. 9 This type of training builds strength in muscles that are not mobilized or poorly mobilized at a steady state. Long-term training can lead to a decline in significant muscles strength. ...
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Introduction Lower limb strength training is one of the daily exercises of jumpers. Heavy squats are a standard method of lower body strength training. The squat is the only compound movement that directly trains “hip strength.” Objective This study aimed to analyze the effect of weighted squats on lower body strength training in long jumpers. Methods 20 jumpers were selected and randomly divided into a general training group and a weighted squat group. Then, the changes in standing triple jump, lateral jump, and Y-axis swing were analyzed before and after training under an experimental protocol. Results The performance of the weighted squat group was better than that of the general training group about the explosive power of the lower body of long jumpers. The data were statistically divergent (P<0.05). There was no significant difference between the two groups in the Y-balance test related to the lower limbs (P>0.05). Conclusion Squatting exercises with weight can improve the explosive power of lower limbs in jumpers. Long jumpers use a variety of jumping exercises to develop the rapid strength needed for their specialties, and this protocol can be added to training for a better athletic outcome. Level of evidence II; Therapeutic studies - investigating treatment outcomes. Keywords Resistance Training; Sports; Athletes; Weight-Bearing
... Tennis is an intermittent high-intensity sport that has become faster over the years, with points (composed of four or five shots) lasting ~8 s followed by 10-25 s of recovery [1]. Depending on the tournament type (the best of three or five sets), a tennis game typically lasts 1-5 h with 20-30% of effective playing time [2,3]. The forehand, similar to the serve, accounts for >25% compared to other common tennis actions (e.g., the backhand and the volley), and consists of preparation, acceleration, impact, and finish phases [4]. ...
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Tennis is an asymmetric sport characterized by a systematic repetition of specific movements that may cause disturbances in muscular strength, power, and torque. Thus, we assessed (i) the torque, power, ratio production, and bilateral asymmetries in the shoulder’s external and internal rotations at 90 and 180°/s angular velocities, and (ii) the point duration influence of the above-mentioned variables. Twenty competitive tennis players performed external and internal shoulder rotations; an isokinetic evaluation was conducted of the dominant and non-dominant upper limbs before and after five and ten forehands. A higher torque production in the shoulder’s internal rotations at 90 and 180°/s was observed for the dominant vs. non-dominant sides (e.g., 63.1 ± 15.6 vs. 45.9 ± 9.8% and 62.5 ± 17.3 vs. 44.0 ± 12.6% of peak torque/body mass, p < 0.05). The peak torque decreased only after ten forehands (38.3 ± 15.8 vs. 38.2 ± 15.8 and 39.3 ± 16.1 vs. 38.1 ± 15.6 Nm, respectively, p < 0.05), but without impacting speed or accuracy. Unilateral systematic actions of tennis players caused contralateral asymmetries, evidencing the importance of implementing compensatory training. The forehand kinematic assessment suggests that racket and wrist amplitude, as well as speed, are important success determinants in tennis.
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Background: Plyometric training (PT) has been researched extensively in athletic populations. However, the effects of PT on tennis players are less clear. Methods: We aim to consolidate the existing research on the effects of PT on healthy tennis players’ skill and physical performance. On 30th May 2022, a comprehensive search of SCOPUS, PubMed, Web of Science, and SPORTDiscus ( via EBSCOhost) databases was performed. PICOS was employed to define the inclusion criteria: 1) healthy tennis players; 2) a PT program; 3) compared a plyometric intervention to a control group or another exercise group, and single-group trials; 4) tested at least one measures of tennis skill or physical performance; and 5) non-randomized study trials and randomized control designs. Individual studies’ methodological quality was evaluated by using the Cochrane RoB-2 and ROBINS-I instruments. Using Grading of Recommendations Assessment, Development, and Evaluation (GRADE), the certainty of the body of evidence for each outcome was assessed, and Comprehensive Meta-Analysis software was employed for the meta-analysis. Results: Twelve studies comprising 443 tennis players aged 12.5–25 years were eligible for inclusion. The PT lasted from 3 to 9 weeks. Eight studies provided data to allow for the pooling of results in a meta-analysis. A moderate positive effect was detected for PT programs on maximal serve velocity (ES = 0.75; p < 0.0001). In terms of measures of physical performance, small to moderate (ES = 0.43–0.88; p = 0.046 to < 0.001) effects were noted for sprint speed, lower extremity muscle power, and agility. While no significant and small effect was noted for lower extremity muscle strength (ES = 0.30; p = 0.115). We found no definitive evidence that PT changed other parameters (i.e., serve accuracy, upper extremity power and strength, reaction time, and aerobic endurance). Based on GRADE, the certainty of evidence across the included studies varied from very low to moderate. Conclusion: PT may improve maximal serve velocity and physical performance components (sprint speed, lower extremity muscular power, and agility) for healthy tennis players; however, more high-quality evidence about the effects of PT on the skill and physical performance of tennis players merits further investigation. Systematic Review Registration: [ ], identifier [INPLASY202250146].
Purpose: This study aimed to verify whether there are differences in physical, technical, and tactical assessment outcomes derived from field-based tests and small-sided games (SSG) in addition to anthropometric and maturational characteristics between players classified as promising and less promising as per the coaches’ perception. Method: A total of 53 male U-15 youth soccer players (age: 14.8 ± 0.2 years, weight: 61.7 ± 6.9 kg, height: 171.8 ± 6.7 cm) and three experienced coaches from three distinct sports clubs were enrolled in this study. Based on the coaches’ perception, players were split into three group levels for both short- and long-term success ranking: (i) promising (PL; top 5 players; n = 15), (ii) intermediate (IL; n = 23) and (iii) less promising (LPL; 5 bottom players; n = 15). The following measures were determined: anthropometry, maturity offset, vertical jump, and aerobic-anaerobic running performance, soccer- specific skills tests, GPS-based running metrics, technical and tactical actions during SSG, and minutes played throughout the season. Results: There were no differences between groups for anthropometrical, maturational, and physical outcomes. PL players in both rankings covered more distances at sprinting and presented more offensive technical and tactical actions during SSG than their LPL peers. PL and IL presented more minutes played in competitive seasons than LPL of short-term ranking. Conclusion: The biggest differences between the players ranked by their coaches were apparent only during a representative game task, emphasizing the importance of SSG as a tool to assess the players’ technical-tactical awareness. In addition to the SSG, the coach’s eye plays a key role during the talent identification and selection process.
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The problem raised is the absence of data on the implementation of prisoner parachute-assisted training methods that can increase the short running speed of amateur football players. This study aims to determine the effect of parachute resistance assisted training methods on running speed. This type of research is quantitative with a quasi-experimental research method with the modified pre-test-post-test group design. The subjects of this study were 10 male amateur football players aged 18-20 years. The test instrument in this study is to measure the running speed using the 30 meters sprint test. Data were analyzed using t-test paired sample t-test at a significance level of 5%. The results of data analysis showed that the parachute resistance assisted training method had an effect on running speed (sig value = 0.000). Thus, the parachute resistance assisted training method is suitable to be applied to increase the running speed of amateur football players. This research can be further developed by increasing the number of samples and applied to professional football players.
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Aloui, G, Hammami, M, Fathloun, M, Hermassi, S, Gaamouri, N, Shephard, RJ, and Chelly, MS. Effects of an 8-week in-season elastic band training program on explosive muscle performance, change of direction, and repeated changes of direction in the lower limbs of junior male handball players. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to examine the effects of incorporating 8 weeks of biweekly lower-limb elastic band training (knee and hip extension) into the in-season regimen of junior handball players. Study participants (30 men, aged 18.7 ± 0.8 years, body mass 81.1 ± 15.4 kg, height 1.82 ± 0.06 m, body fat: 15.5 ± 5.2%) were randomly assigned between control and experimental groups. Measures obtained before and after intervention included a cycle ergometer force-velocity test, force platform determinations of squat and countermovement jump characteristics, sprint times (5 and 30 m), repeated change-of-direction (RCOD) and change-of-direction (T-half, COD) tests, 1 repetition maximum (RM) half back squat, and anthropometric estimates of limb muscle volumes. Small to trivial improvements of experimental subjects relative to control subjects included peak power (p < 0.001), 1RM strength measures (p < 0.01), sprint times (p < 0.001 for 5 m; p < 0.05 for 30 m), COD (p < 0.01), and all RCOD parameters (p < 0.05) except the RCOD fatigue index. However, vertical jump parameters and limb volumes remained unchanged relative to controls. It may be concluded that adding biweekly elastic band training to a standard conditioning regimen yields small gains in measures that likely have an important influence on handball performance, particularly the ability to sprint, change direction, and make repeated changes of direction. Accordingly, such simple exercises can usefully be adopted as a component of handball training.
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Background: Sprinting is key in the development and final results of competitions in a range of sport disciplines, both individual (e.g., athletics) and team sports. Resisted sled training (RST) might provide an effective training method to improve sprinting, in both the acceleration and the maximum-velocity phases. However, substantial discrepancies exist in the literature regarding the influence of training status and sled load prescription in relation to the specific components of sprint performance to be developed and the phase of sprint. Objectives: Our objectives were to review the state of the current literature on intervention studies that have analyzed the effects of RST on sprint performance in both the acceleration and the maximum-velocity phases in healthy athletes and to establish which RST load characteristics produce the largest improvements in sprint performance. Methods: We performed a literature search in PubMed, SPORTDiscus, and Web of Science up to and including 9 January 2018. Peer-reviewed studies were included if they met all the following eligibility criteria: (1) published in a scientific journal; (2) original experimental and longitudinal study; (3) participants were at least recreationally active and towed or pulled the sled while running at maximum intensity; (4) RST was one of the main training methods used; (5) studies identified the load of the sled, distance covered, and sprint time and/or sprint velocity for both baseline and post-training results; (6) sprint performance was measured using timing gates, radar gun, or stopwatch; (7) published in the English language; and (8) had a quality assessment score > 6 points. Results: A total of 2376 articles were found. After filtering procedures, only 13 studies were included in this meta-analysis. In the included studies, 32 RST groups and 15 control groups were analyzed for sprint time in the different phases and full sprint. Significant improvements were found between baseline and post-training in sprint performance in the acceleration phase (effect size [ES] 0.61; p = 0.0001; standardized mean difference [SMD] 0.57; 95% confidence interval [CI] - 0.85 to - 0.28) and full sprint (ES 0.36; p = 0.009; SMD 0.38; 95% CI - 0.67 to - 0.10). However, non-significant improvements were observed between pre- and post-test in sprint time in the maximum-velocity phase (ES 0.27; p = 0.25; SMD 0.18; 95% CI - 0.49 to 0.13). Furthermore, studies that included a control group found a non-significant improvement in participants in the RST group compared with the control group, independent of the analyzed phase. Conclusions: RST is an effective method to improve sprint performance, specifically in the early acceleration phase. However, it cannot be said that this method is more effective than the same training without overload. The effect of RST is greatest in recreationally active or trained men who practice team sports such as football or rugby. Moreover, the intensity (load) is not a determinant of sprint performance improvement, but the recommended volume is > 160 m per session, and approximately 2680 m per week, with a training frequency of two to three times per week, for at least 6 weeks. Finally, rigid surfaces appear to enhance the effect of RST on sprint performance.
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Resisted sprint training consists of performing overloaded sprints, which may produce greater effects than traditional sprint training. We compared a resisted sprint training with overload control versus an unresisted sprint training program on performance in soccer players. Eighteen elite athletes were randomly assigned to resisted (RST) or unresisted sprint training protocol (UR). Before and after a 6-week training period, sprinting ability, change of direction speed (COD), vertical jumps (SJ and CMJ), mean power (MP) and mean propulsive power (MPP) at distinct loads were assessed. Both groups improved sprinting ability at all distances evaluated (5m: UR = 8%, RST = 7%; 10m: UR = 5%, RST = 5%; 15m: UR = 4%, RST = 4%; 20m: UR = 3%, RST = 3%; 25m: UR = 2%, RST = 3%;), COD (UR = 6%; RST = 6%), SJ (UR = 15%; RST = 13%) and CMJ (UR = 15%; RST = 15%). Additionally, both groups increased MP and MPP at all loads evaluated. The between-group magnitude-based inference analysis demonstrated comparable improvement ("trivial" effect) in all variables tested. Finally, our findings support the effectiveness of a short-term training program involving squat jump exercise plus sprinting exercises to improve the performance of soccer players.
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The aim of this study was to compare the effects of two different mixed training programs (optimum power load [OPL] + resisted sprints [RS] and OPL + vertical/horizontal plyometrics [PL]) on neuromuscular performance of elite soccer players during a short-term training preseason. Eighteen male professional soccer players took part in this study. The athletes were pair-matched in two training groups: OPL + RS and OPL + PL. Unloaded and resisted sprinting speeds at 5-, 10-, 20-, and 30-m, change of direction (COD) speed, and performance in the squat jump (SJ), countermovement jump (CMJ), and horizontal jump (HJ) were assessed pre- and post- a 5-week training period. Magnitude based inference with the effect sizes were used for data analysis. A possible increase in the SJ and CMJ heights and a likely increase in the HJ distance were observed in the OPL + PL group. Meaningful improvements were observed in the COD speed test for both training groups comparing pre- and post-measures. In both unloaded and resisted sprints, meaningful decreases were observed in the sprinting times for all distances tested. This study shows that a mixed training approach which comprises exercises and workloads able to produce positive adaptations in different phases of sprinting can be a very effective strategy in professional soccer players. Moreover, the possibility of combining optimum power loads with resisted sprints and plyometrics emerges as a novel and suitable option for coaches and sport scientists, due to the applicability and efficiency of this strength-power training approach.
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The aim of the present study was to analyze the effects of a 5-week neuromuscular training (NMT) implemented before or after a tennis session in pre-pubertal players on selected components of physical fitness. Sixteen elite and well-trained tennis players with a mean age of 12.9 ± 0.4 years participated in this study, and were assigned to either a training group performing NMT before tennis specific training (BT; n=8) or a group that conducted NMT after tennis specific training (AT; n=8). Pre and post-tests included: speed (5,10 and 20 m); modified 5-0-5 agility test; countermovement jump (CMJ); overhead medicine ball throw (MBT); and serve velocity (SV). Results showed that the BT group achieved positive effects from pre- to post-test measures in speed (d = 0.52, 0.32 and 1.08 for 5, 10 and 20 m respectively) 5-0-5 (d = 0.22), CMJ (d = 0.29), MBT (d = 0.51) and SV (d = 0.32), while trivial (10 m, 20 m, CMJ, SV, MBT) or negative effects (d = -0.19 and -0.24 for 5 m and 5-0-5 respectively), while trivial or negative effects were reported for the AT group. The inclusion of a NMT session before the regular tennis training led to positive effects from pre- to post-test measures in performance-related variables (i.e., jump, sprint, change of direction capacity, as well as upper body power), while conducting the same exercise sessions after the regular tennis training was not accompanied by the same improvements.
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Purpose: The effects of different loads on kinematic and kinetic variables during sled towing were investigated with the aim to identify the optimal overload for this specific sprint training. Methods: Thirteen male sprinters (100m PB: 10.91±0.14 s) performed 5 maximal trials over a 20m distance in the following conditions: unloaded (UL) and with loads from +15% to +40% of the athlete's body mass (BM). In these calculations the sled mass and friction were taken into account. Contact and flight times (CT, FT), step length (SL), horizontal hip velocity (vh) and relative angles of hip, knee and ankle (at touch-down and take-off) were measured step-by-step. In addition, the horizontal force (Fh) and power (Ph) and the maximal force (Fh0) and power (Ph0) were calculated. Results: vh, FT and SL decreased while CT increased with increasing load (P < .001). These variables changed significantly also as a function of the step number (P < .01) except between the two last steps. No differences were observed in Fh among loads but Fh was larger in sled towing compared to UL. Ph was unaffected by load up +20%BM but decreased with larger loads. Fh0 and Ph0 were achieved at +20%BM. Up to +20%BM no significant effects on joint angles were observed at touch-down and take-off, while at loads >+30%BM joint angles tend to decrease. Conclusions: The +20%BM condition represents the optimal overload for peak power production: at this load sprinters reach their highest power without significant changes in their running technique (e.g. joint angles).
Purpose:: To describe the load-velocity relationship and the effects of increasing loads on spatio-temporal and derived kinetics variables of sprinting using weighted vest (WV) in soccer players and determining the load that maximized power output. Methods:: Twenty-three soccer players (age: 20.8±1.5 years) performed ten maximal 30-m sprints wearing a WV, with five different loads (0, 10, 20, 30 and 40% body mass (BM). Sprint velocity and time were collected using a radar device and wireless photocells. Mechanical outputs were computed using a recently developed valid and reliable field method that estimates the step-averaged ground reaction forces (GRF) during over ground sprint acceleration from anthropometric and spatio-temporal data. Raw velocity-time data were fitted by an exponential function and used to calculate the net horizontal GRF and horizontal power output. Individual linear force-velocity relationships were then extrapolated to calculate the theoretical maximum horizontal force (F0) and velocity, and the ratio of force application (RF: proportion of the total force production that is directed forward at sprint start). Results:: Magnitude-based inferences showed an almost certain decrease on F0 (effect size [ES]=0.78-3.35), maximum power output (ES=0.78-3.81), and maximum ratio of force (ES=0.82-3.87) as the load increased. The greatest changes occurred with loads heavier than 20% BM, especially in RF. Additionally, the maximum power was achieved under unloaded condition. Conclusions:: Increasing load on WV sprinting affects the spatio-temporal and kinetic variables. The greatest change in RF happened with loads heavier than 20% BM. Thus, we recommend the use of loads ≤20% BM for WV sprinting.
This study aimed to compare the effects of 6 weeks resistance training (RT) with combined RT and loaded change of direction (CD) exercise on muscle strength and repeated sprint ability (RSA) in futsal players. Thirty-four players were randomly assigned into three groups: full squat group (SG), combined full squat and CD group (S+CDG), and control group (CG). The RT for SG consisted of full squat with low-load (~45-60% 1RM) and low-volume (4-6 repetitions), whereas the S+CDG performed the same RT program combined with loaded CD. Estimated one-repetition maximum (1RMest) and variables derived from RSA test including mean sprint time (RSAmean), best sprint time (RSAbest), percent sprint decrement (Sdec), mean ground contact time (GCTmean) and mean step length (SL) were selected as testing variables. Changes in sprint time and GCT in each sprint were also analysed. Both experimental groups showed significant (P<0.05-0.001) improvements for 1RMest, RSAbest and first and second sprint time. In addition, S+CDG achieved significant (P<0.05-0.001) improvements in RSAmean, sprint time (from fifth to ninth sprint) and GCT (from third to eighth sprint). These results indicate that only 6 weeks of RT combined with CD in addition to routine futsal training is enough to improve RSA in futsal players.
The aim of this study was to analyse the effects of a combined strength-training programme (full-back squat, YoYo(TM) leg curl, plyometrics and sled towing exercises) on performance in elite young soccer players and to examine the effects when this training programme was performed one or two days per week. Thirty-six male soccer players (U-17 to U-19) were recruited and assigned to experimental groups (EXP1: 1 s w(-1); EXP2: 2 s w(-1)) or a control group (CON). Performance was assessed through a countermovement jump (CMJ) test (relative peak power [CMJPP] and CMJ height [CMJH]), a 20-m linear sprint test with split-times at 10-m, and a change of direction test (V-cut test) 1 week before starting the training programme and also 1 week after performing such training programme. Within-group analysis showed substantial improvements in CMJ variables (ES: 0.39-0.81) and COD (ES: 0.70 and 0.76) in EXP1 and EXP2, while EXP2 also showed substantial enhancements in all linear sprinting tests (ES: 0.43-0.52). Between-group analysis showed substantially greater improvements in CMJ variables (ES: 0.39-0.68) in experimental groups in comparison to CON. Furthermore, EXP2 achieved a substantial better performance in 20-m (ES: 0.48-0.64) than EXP1 and CON. Finally, EXP2 also showed greater enhancements in 10-m (ES: 0.50) and V-cut test (ES: 0.52) than EXP1. In conclusion, the combined strength-training programme improved jumping ability, independently of training frequency, though the achievement of two sessions per week also enhanced sprinting abilities (linear and COD) in young soccer players.
The purpose of this study was to analyze the effects of playing two tennis matches on the same day on physical performance in young tennis players. Twelve well-trained young tennis players took part in a simulated tennis competition consisting of two tennis matches on the same day (morning and afternoon sessions). Before and the day after the competition, physical performance was measured using a battery of countermovement jumps (CMJ), a 10-m sprint, the 5-0-5 agility test, hip, grip and shoulder maximal isometric strength, shoulder range of motion (ROM) and a serve velocity test. Post-competition results showed reduced performance in 10-m (-3.3%, effect size (ES)= small), dominant-and-non-dominant 5-0-5 agility test (-4.6%, ES=moderate; -4.2%, ES=moderate, respectively), bilateral (-5.2%, ES=small) and unilateral CMJ (dominant leg: -7.2%, ES=small; non-dominant leg: -9.1%, ES=small). Both dominant and non-dominant shoulder external rotation (ER) ROM increased (12.2%, ES=moderate; 5.6%, ES=small) while internal rotation (IR) decreased (-4.2%, ES=small; -3.3%, ES=small) in the post-competition tests, together with the dominant-shoulder ER (-10.7%, ES=moderate) and IR (-9.3%, ES=small) strength. Physical impairments occurred in neuromuscular performance variables involving lower (e.g. jumping, sprinting and change of direction) and upper (e.g. isometric strength and range of motion) limbs the day after playing a competition with two consecutive matches on the same day. These alterations in neuromuscular and sport-specific performance need to be taken into consideration when planning tournament schedules for young tennis players, as well as preparing match and recovery strategies.