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Less is more: Standard warm-up causes fatigue and less warm-up permits greater cycling power output
Abstract and Figures
The traditional warm-up (WU) used by athletes to prepare for a sprint track cycling event involves a general WU followed by a series of brief sprints lasting ≥ 50 min in total. A WU of this duration and intensity could cause significant fatigue and impair subsequent performance. The purpose of this research was to compare a traditional WU with an experimental WU and examine the consequences of traditional and experimental WU on the 30-s Wingate test and electrically elicited twitch contractions. The traditional WU began with 20 min of cycling with a gradual intensity increase from 60% to 95% of maximal heart rate; then four sprints were performed at 8-min intervals. The experimental WU was shorter with less high-intensity exercise: intensity increased from 60% to 70% of maximal heart rate over 15 min; then just one sprint was performed. The Wingate test was conducted with a 1-min lead-in at 80% of optimal cadence followed by a Wingate test at optimal cadence. Peak active twitch torque was significantly lower after the traditional than experimental WU (86.5 ± 3.3% vs. 94.6 ± 2.4%, P < 0.05) when expressed as percentage of pre-WU amplitude. Wingate test performance was significantly better (P < 0.01) after experimental WU (peak power output = 1,390 ± 80 W, work = 29.1 ± 1.2 kJ) than traditional WU (peak power output = 1,303 ± 89 W, work = 27.7 ± 1.2 kJ). The traditional track cyclist's WU results in significant fatigue, which corresponds with impaired peak power output. A shorter and lower-intensity WU permits a better performance.
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... In the studies by Tomaras et al. (2011) and Zhang et al. (2024), an intermittent sprint warm-up and a PAP warm-up were applied, respectively, with both observing an increase in power output after rest 19,20 . Furthermore, Munro et al. (2017) explored different strategies of a high inertia PAP protocol in track cycling, revealing the feasibility of applying PAP activation strategies to enhance average power 13 . ...
... In the studies by Tomaras et al. (2011) and Zhang et al. (2024), an intermittent sprint warm-up and a PAP warm-up were applied, respectively, with both observing an increase in power output after rest 19,20 . Furthermore, Munro et al. (2017) explored different strategies of a high inertia PAP protocol in track cycling, revealing the feasibility of applying PAP activation strategies to enhance average power 13 . ...
The study aimed to optimise post-activation potentiation (PAP) strategies for Rider 1 in elite team sprints to improve performance over 250 m (opening lap), with a focus on female cyclists. Eight national-level track cyclists participated in this study, undergoing four sets of activation strategies: control (CON), dynamic high inertia (DYN, 4 × 4 pedal strokes), isometric contraction (ISO, 4 × 4 s, 4 angles), and back squat activation (BSQ, 4 × 4 rep, 80%1RM). The tests were divided into pre-activation and post-activation phases, including measurements at 4 min, 8 min, and 12 min after activation. The tests included a 250 m time trial (TT) and segment timing, with measurements of peak torque, peak power, average power, and cadence. The mean cadence, torque, and power for the first 62.5 m of pedal revolutions were collected. Paired-sample t-tests were used to assess activation differences. Multiple group comparisons were conducted using analysis of variance (ANOVA). The Bonferroni correction was used to control Type I errors. For significant activation strategies, linear or non-linear regression was applied to extrapolate the torque-cadence and power-cadence profiles, and the parameter differences were examined to investigate profile changes. Cohen’s d and Cohen’s f were used as effect sizes. After DYN activation, the 250 m TT significantly improved (p = 0.018), primarily through a reduction in the 62.5 m time (p = 0.006) and an increase in peak torque (p = 0.018). After 12 min of ISO activation, the 250 m TT showed a large effect but did not reach the significance level under Bonferroni correction (p = 0.135, d = 0.860), with a notable reduction in the 62.5 m time (p = 0.003). PAP can be strategically employed to enhance the performance of elite female Rider 1 in team sprints.
... Warm-up methods are broadly classified as active (direct physical activity) and passive (indirect external stimuli), each with distinct effects. However, while active warm-ups can improve performance, excessive exertion may lead to fatigue and diminished performance [7]. ...
Background
Warm-ups optimize athletic performance; however, excessively active warm-ups may induce fatigue. Passive warm-up strategies, including thermotherapy, offer physiological benefits, although their immediate performance effects are unclear. High-voltage pulsed-current (HVPC) electrical stimulation, used in rehabilitation to activate deep muscles, has not been fully explored as a warm-up strategy. This study examined the immediate effects of short-duration HVPC stimulation combined with abdominal hollowing exercises on jump performance.
Methods
A total of 36 healthy participants were randomly assigned to the HVPC (n = 18) or control (n = 18) group. The HVPC group performed abdominal hollowing exercises with HVPC stimulation for 4 minutes, while the control group performed the exercises without electrical stimulation. The rebound jump (RJ) index, jump height, and ground contact time were measured before and after the intervention. A paired t-test was used to compare the pre- and post-experiment measurements.
Results
The HVPC group showed a significant increase in jump height (pre 31.95 ± 6.42 vs post 33.64 ± 6.61) (p < 0.05) and RJ index (pre 1.67 ± 0.47 vs post 1.75 ± 0.44) (p < 0.05) post-intervention, whereas the ground contact time remained unchanged. The control group showed no significant changes in any parameter.
Conclusion
Short-duration HVPC stimulation combined with abdominal hollowing exercises improved jump performance. HVPC-assisted warm-ups show potential, particularly in sports.
... Participants subsequently undertook a warm-up comprising of 12-min cycling at a power output of 1.5 W·kg −1 on a static cycle ergometer (Excalibur, Lode, Groningen, Netherlands). A 5-s sprint was conducted at a power output of 7.5 W·kg −1 after the initial 6 min to prime the physiological systems for the subsequent maximal cycle test (Tomaras & MacIntosh, 2011). ...
This study evaluated the relationship between muscle oxygen saturation (SmO2) and the maximal blood lactate accumulation rate (vLamax) during three test durations (10, 15 and 30 s) to validate the optimal test duration of vLamax protocol. Thirteen developmental trained males (age: 27 ± 6 years and peak power: 1133 ± 185W and 14.88 ± 1.61 W·kg⁻¹) performed three maximal cycle tests (10, 15 and 30 s). Performance metrics were measured throughout; peak power, mean power, and cadence. vLamax was determined using blood lactate concentrations following each test. SmO2 of the vastus lateralis was measured using a MOXY device via near‐infrared spectroscopy, throughout all experimental conditions. The shortest test (10 s) produced a significantly (p = 0.005; p < 0.001) higher vLamax (0.83 ± 0.15 mmol·L⁻¹·s⁻¹) than 15 s (0.67 ± 0.13 mmol·L⁻¹·s⁻¹) and 30 s (0.43 ± 0.06 mmol·L⁻¹·s⁻¹). Three relationships between SmO2 kinetics and vLamax were observed: (1) a very strong inverse relationship (r = −0.994, p < 0.001) between SmO2 desaturation and vLamax time dependent kinetics, (2) a significant inverse relationship (r = −0.648, p < 0.001) between SmO2 time spent at the nadir and vLamax and (3) a moderate relationship (r = 0.508, p = 0.11) and similar time to attain the SmO2 nadir (8.47 ± 1.50s) and vLamax (8.92 ± 0.77s). These results validate the 10‐s test duration for determination of vLamax verified with mathematical modelling predicting peak vLamax occurs at ∼9 s. SmO2 desaturation closely reflects the vLamax kinetics, with the time points of the SmO2 nadir and peak vLamax closely corresponding.
... Blagrove et al. (2019) described that warm-up strategy in endurance athletes typically aims to achieve acute metabolic and cardiovascular adjustment which enhances the oxygen uptake, kinetic response, elevation of baseline oxygen consumption and acidaemia, which indirectly produces acute muscle preparedness. A study by Tomaras & MacIntosh (2011) on warm-up techniques indicates that athletes have been using the traditional warming-up method involving a general warm-up followed by a series of brief sprints lasting more than 50 minutes in total. This type of warm-up takes a longer time and gives lesser muscle readiness. ...
Post Activation Potentiation (PAP) warm-up strategies are gaining attention for their potential to enhance athletic performance. This study aims to compare the effects of unilateral PAP (UPAP) and bilateral PAP (BPAP) on cycling performance. Using a randomised crossover experimental design, 50 trained recreational male cyclists, aged 18 to 40, participated. Each cyclist’s regimen included 4 sets of 5 Repetition Maximum (RM) for back squats (BPAP) and rear leg elevated split squats (UPAP). The exercises were performed on separate occasions, followed by a Power Profile Test developed by the World Cycling Centre (WCC-PTT). Results showed that 85% of 1RM BPAP significantly improved 30-second average power, relative average power, average cadence, and average torque. Conversely, 42.5% 1RM UPAP notably enhanced peak power, peak cadence, and peak torque, with significant improvements in 6-second average power, relative average power, average cadence, and average torque. When the intensity of UPAP was reduced to 42.5%, significant improvements in average power output and average cadence were observed in the 4-minute test. This study highlights the importance of tailoring PAP type and intensity to the specific demands of the sport or event to enhance performance by effectively targeting relevant muscle groups.
... Strain arising from maintaining this specific posture is often a consequence of equipment not being adjusted to the cyclist's body dimensions and physical conditions [3]. Additionally, improper or absent warm-up routines serve as an additional risk factor [4]. Muscle activation asymmetries also constitute a risk factor for the occurrence of spinal pain. ...
Background: Cycling involves specific body positions that, when maintained for prolonged periods, may affect spinal curvature and increase the risk of pain-related issues. This study aimed to evaluate sagittal spinal curvatures, the prevalence of pain in spinal segments, and their interrelation among amateur road cyclists. Methoods: The research included 30 male participants aged 18–48 years. Pain severity was assessed using the Visual Analog Scale (VAS) and Laitinen scale, while spinal curvature was evaluated with an electronic inclinometer. Results: Results showed no statistically significant differences in spinal curvature angles between cyclists with and without pain complaints (p = 0.056). However, tendencies were noted, such as higher mean VAS scores for lower back pain (4.90) compared to neck pain (3.38), and variations in parameters like Beta, LL, and KGP. Conclusions: While the findings did not confirm clear distinctions, they suggest trends indicating potential links between spinal curvatures and pain occurrence. These results underscore the importance of further studies involving larger cohorts to verify these observations and explore the biomechanical adaptations associated with amateur cycling. Insights from such research could inform strategies for preventing and managing spinal pain among cyclists.
... Blagrove et al. (2019) described that warm-up strategy in endurance athletes typically aims to achieve acute metabolic and cardiovascular adjustment which enhances the oxygen uptake, kinetic response, elevation of baseline oxygen consumption and acidaemia, which indirectly produces acute muscle preparedness. A study by Tomaras & MacIntosh (2011) on warm-up techniques indicates that athletes have been using the traditional warming-up method involving a general warm-up followed by a series of brief sprints lasting more than 50 minutes in total. This type of warm-up takes a longer time and gives lesser muscle readiness. ...
... Another critical role of CAs is in optimizing the efficiency of warm-ups. An appropriate CA can accelerate performance enhancement [188,189]. This was exemplified during re-warmups in team sports, where a brief 2-min explosive task could restore athletic performance [6,184]. ...
Background
Post-activation performance enhancement (PAPE) has demonstrated efficacy in acutely improving athletic performance. However, its distinction from general warm-up (GW) effects remains ambiguous, and experimental designs adopted in most PAPE studies exhibit important limitations.
Objectives
The aims of this work are to (i) examine the effects of research methodology on PAPE outcomes, (ii) explore PAPE outcomes in relation to comparison methods, performance measures, GW comprehensiveness, recovery duration, participants’ characteristics, conditioning activity (CA) parameters, and (iii) make recommendations for future PAPE experimental designs on the basis of the results of the meta-analysis.
Methods
Four databases were searched for peer-reviewed English-language literature. Risk of bias was assessed using a modified Cochrane Collaboration’s tool and PEDro scale. PAPE groups were compared with control groups, pre-conditioning activity (pre-CA) performances were compared with post-conditioning activity (post-CA) performances throughout a verification test in PAPE groups, and control groups were compared before and after the “rest” period using a three-level meta-analysis. Further analyses, including subgroup analysis and both linear and nonlinear meta-regression methods, were used to explore the effect of different moderating factors on PAPE magnitude. A subgroup analysis of GW comprehensiveness was conducted using four classification methods. One method classified GW as non-comprehensive (stretching or jogging only), partially comprehensive (stretching, jogging, and low-intensity self-weighted dynamic exercises), and comprehensive (adding maximal or near-maximal intensity CAs to a partially comprehensive GW). The other three classifications were adjusted according to the type and number of GW exercises. Certainty of evidence was assessed using the GRADE approach.
Results
The final analysis included 62 PAPE studies (1039 participants, male: n = 857, female: n = 182) with a high risk of bias and low certainty of pooled evidence. A trivial PAPE effect was observed from pre- to post-CA (effect size [ES] = 0.12, 95% CI [0.06 to 0.19], prediction intervals [PI] = − 0.29 to 0.54); a small PAPE effect was observed when compared with a control group (ES = 0.30, 95% CI [0.20 to 0.40], PI [− 0.38 to 0.97]). The slightly greater effect against control resulted from a small decrease in performance in control groups (ES = − 0.08, 95% CI [− 0.13 to − 0.03], PI [− 0.30 to 0.14]), but there was no relationship with between PAPE recovery time (β = − 0.005, p = 0.149). Subgroup analyses showed that PAPE magnitude was greater for non-comprehensive GWs (ES = 0.16) than comprehensive (ES = 0.01) and partially comprehensive GWs (ES = 0.11). In contrast, the control group showed a decline in performance after comprehensive GW (ES = − 0.20). An inverted U-shaped PAPE was noted as a function of recovery time. In some cases, PAPE appeared to manifest at < 1 min post CA. Additionally, participants with longer training experience (ES = 0.36) and higher training levels (ES = 0.38) had larger PAPE magnitudes. PAPE effect was higher in females (ES = 0.51) than males (ES = 0.32) and mixed groups (ES = 0.16) but did not reach a significant difference (p > 0.05). Plyometric exercise (ES = 0.42) induced greater PAPE amplitude than traditional resistance exercise (ES = 0.23), maximal isometric voluntary contraction (ES = 0.31) and other CA types (ES = 0.24).
Conclusions
Although the overall pooled results for both PAPE pre- versus post-CA and PAPE versus control group comparisons showed significant improvement, the wider and past-zero prediction intervals indicate that future studies are still likely to produce negative results. The comprehensiveness of the GW, the time between GW and the pre-CA test, participant sex, training level, training experience, type of CA, number of CA sets, and recovery time after CA all influence the PAPE magnitude. The PAPE magnitude was trivial after comprehensive GW, but it was greater in studies with a control group (i.e., no CA) because performance decreased over the control period, inflating the PAPE effect. Finally, two theoretical models of PAPE experimental design and suggestions for methodological issues are subsequently presented. Future studies can build on this to further explore the effects of PAPE.
Protocol Registration
The original protocol was prospectively registered (osf.io/v7sbt) with the Open Science Framework.
... Limited data also suggest that the development of land-based power contributes to surfing prowess in recreational surfers (2,12). Thus, a warm-up is important for subsequent performance, likely including in surfing, and this notion is supported by a meta-analysis that shows that 79% of research has demonstrated an improvement in performance with a warmup (13)(14)(15)). However, for surfing, because data are limited, and owing to its unique nature of requiring physical exertion above and below water, further research is needed to establish how closely knowledge of warm-up from other sports translates to it. ...
Surfing is a high participation sport, yet little sport science research exists regarding competitive performance in surfing. Given surfing's inclusion as an Olympic sport from the 2020 Tokyo Olympics onwards, an examination of performance would seem useful. In numerous land-based sports, and in swimming, the importance of a warm-up and muscle heat is well documented. However, surfing is a unique sport in that it is undertaken both above and below water. Therefore, the aim of this study was to explore the effectiveness of a warm-up in terms of readiness to perform in surfing. We discuss this in the context of thermal regulation, hormone profile change, and the subsequent expression of “power” on waves—a key criteria that surfers are scored for. Nineteen advanced level surfers (i.e., competitive at just below national level in Australia; n = 15 males and n = 4 females) with mean (±SD) age, height, and weight of 24.5 ± 11.6 years, 174.7 ± 9.1 cm, and 67.7 ± 10.2 kg, respectively, were recruited. We adopted a repeated measures pre- and post-design whereby participants engaged in several simulated surfing competitions in an artificial wave pool; once after an active warm-up combined with a passive heat retention strategy (i.e., wrapping themselves in survival blankets—treatment), and once after no warm-up (control). Saliva samples were collected pre- and post-active warm-up, or at equivalent times under control conditions, for the measurement of testosterone and cortisol. Increases in these hormones have previously been associated with an enhanced readiness to compete. Our results demonstrate a clear thermoregulatory benefit from the treatment, with the participants’ core body temperatures typically higher from the end of the warm-up to the end of the surf session following treatment (p ≤ 0.03), and a magnitude of increase in core body temperature once in the water that is greater following treatment (p = 0.01). A small magnitude upward change in testosterone (p = 0.01) and cortisol (p ≤ 0.001) following warm-up was also observed. Finally, warm-up was associated with an improved wave performance compared with the control, with a 20% increase in the performance score typically observed (p ≤ 0.01). We argue that the improved thermal profile may have influenced power and, as such, surfing performance was enhanced.
The aim of this study is to compile and analyze the existing knowledge on post activation potentiation (PAP). By examining the mechanisms of PAP, its effects on performance, and its role in sports applications in detail, this study seeks to contribute to the sports sciences literature. The relationship between PAP and fatigue, its integration into training protocols, and its effects on individual differences will be addressed. The study aims to lay the groundwork for the development of strategies to enhance athletes' performance. Research indicates that PAP affects performance metrics such as jumping, sprinting, strength, and endurance. The literature highlights that many of these effects vary depending on time. Studies show that PAP effects are more pronounced in stronger individuals. Particularly, plyometric exercises and less deep squat movements have been observed to enhance the PAP effect. This creates favorable conditions for muscle fibers to generate potential more effectively. However, the functional significance of PAP in terms of performance and its long-term effects are not yet fully understood, necessitating further research in this area.
Background: Whilst muscle contractility increases with muscle temperature, there is no consensus on the best warm-up protocol to use before resistance training or sports exercise due to the range of possible warm-up and testing combinations available. Objectives: To determine the effects of different warm-up types (active, exercise-based vs. passive) on muscle function tested using different activation methods (voluntary vs. evoked) and performance test criteria (maximum force vs. rate-dependent contractile properties), with consideration of warm-up task specificity (specific vs. non-specific), temperature measurement sites (muscle vs. skin), baseline temperatures, and subject-specific variables (training status and sex). Methods: A systematic search was conducted on 6 electronic databases. Random-effects meta-analyses and meta-regressions were used to compute the effect sizes (ES±95% confidence intervals) to examine the effects of warm-up type, activation method, performance criterion, subject characteristics, and study design on temperature-related performance enhancement. Results: The search yielded 1272 articles, of which 33 met the inclusion criteria (n=921). Increasing temperature positively affected both voluntary (3.7±1.8%/°C, ES=0.28 [0.14, 0.41]) and evoked (3.2±1.5%/°C, ES=0.65 [0.29, 1.00]) rate-dependent contractile properties (dynamic, fast-velocity force production and rate of force development [RFD]) but not maximum force production (voluntary: - 0.2±0.9%/°C, ES=0.08 [-0.05, 0.22]; evoked: -0.1±0.8%/°C, ES=-0.20 [-0.50, 0.10]). Active warm-up did not induce greater enhancements in rate-dependent contractile properties (p=0.284), maximum force production (p=0.723), or overall function (pooled, p=0.093) than passive warm-up. Meta-regressions did not reveal a significant effect of study design, temperature measurement site, warm-up task specificity, training status, or sex on the effect of increasing temperature (p>0.05). Conclusion: Increasing muscle temperature significantly enhances rate-dependent contractile function (RFD and muscle power) but not maximum force in both evoked and voluntary contractions. In contrast to expectation, no effects of warm-up modality (active vs. passive), study design (full data vs. no control), or temperature measurement site (muscle vs. skin) were detected, although a lack of data prevented robust subgroup analysis. Future research should further investigate the effect of increasing temperature on muscle function using well-designed and well-controlled study designs (i.e., randomized controlled trials).
While warm up is considered to be essential for optimum performance, there is little scientific evidence supporting its effectiveness in many situations. As a result, warm-up procedures are usually based on the trial and error experience of the athlete or coach, rather than on scientific study. Summarising the findings of the many warm-up studies conducted over the years is difficult. Many of the earlier studies were poorly controlled, contained few study participants and often omitted statistical analyses. Furthermore, over the years, warm up protocols consisting of different types (e.g. active, passive, specific) and structures (e.g. varied intensity, duration and recovery) have been used. Finally, while many studies have investigated the physiological responses to warm up, relatively few studies have reported changes in performance following warm up. The first part of this review critically analyses reported changes in performance following various active warm-up protocols. While there is a scarcity of well-controlled studies with large subject numbers and appropriate statistical analyses, a number of conclusions can be drawn regarding the effects of active warm up on performance. Active warm up tends to result in slightly larger improvements in short-term performance (10 seconds, but 2). While active warm up has been reported to improve endurance performance, it may have a detrimental effect on endurance performance if it causes a significant increase in thermoregulatory strain. The addition of a brief, task-specific burst of activity has been reported to provide further ergogenic benefits for some tasks. By manipulating intensity, duration and recovery, many different warm-up protocols may be able to achieve similar physiological and performance changes. Finally, passive warm-up techniques may be important to supplement or maintain temperature increases produced by an active warm up, especially if there is an unavoidable delay between the warm up and the task and/or the weather is cold. Further research is required to investigate the role of warm up in different environmental conditions, especially for endurance events where a critical core temperature may limit performance.
We have studied the effect of myosin P-light chain phosphorylation on the isometric tension generated by skinned fibers from rabbit psoas muscle at 0.6 and 10 microM Ca2+. At the lower Ca2+ concentration, which produced 10-20% of the maximal isometric tension obtained at 10 microM Ca2+, addition of purified myosin light chain resulted in a 50% increase in isometric tension which correlated with an increase in P-light chain phosphorylation from 0.10 to 0.80 mol of phosphate/mol of P-light chain. Addition of a phosphoprotein phosphatase reversed the isometric tension response and dephosphorylated P-light chain. At the higher Ca2+ concentration, P-light chain phosphorylation was found to have little effect on isometric tension. Fibers prepared and stored at -20 degrees C in a buffer containing MgATP, KF, and potassium phosphate incorporated 0.80 mol of phosphate/mol of P-light chain. Addition of phosphoprotein phosphatase to these fibers incubated at 0.6 microM Ca2+ caused a reduction in isometric tension and dephosphorylation of the P-light chain. There was no difference before and after phosphorylation of P-light chain in the normalized force-velocity relationship for fibers at the lower Ca2+ concentration, and the extrapolated maximum shortening velocity was 2.2 fiber lengths/s. Our results suggest that in vertebrate skeletal muscle, P-light chain phosphorylation increases the force level at submaximal Ca2+ concentrations, probably by affecting the interaction between the myosin cross-bridge and the thin filament.
Slowing of relaxation is one of the anticipated changes in the contraction of fatigued skeletal muscle. However, interpretation of the mechanism(s) contributing to slowed relaxation may be affected by the measurement technique employed. In this study, relaxation was measured in three ways: (i) traditional half-relaxation time; (ii) peak rate of relaxation; and (iii) late relaxation time, measured from 50 to 25% of peak developed tension. When rat gastrocnemius muscle was stimulated indirectly in situ at 10 Hz, developed tension increased in 10 s to 185%, then decreased to 39% after 1 min with little additional change over the next 4 min. After 10 s of inactivity, developed tension was 60% of the initial value, but did not recover further over the next 20 min. The half-relaxation time transiently decreased at the start of stimulation, then by 20 s was considerably prolonged. Within 10 s of recovery, half-relaxation time returned to prestimulation values but became prolonged again by 10 min of recovery. The peak rate of relaxation was proportional to the developed tension at all times except 2.5-10 s of 10 Hz stimulation, at which time acceleration of relaxation was evident, and 15-20 s of the 10 Hz stimulation when it was relatively decreased. The late relaxation time increased during the repetitive stimulation, returned to control level early in recovery, then increased again, by 5 min of recovery. The diverse responses indicated by these indices of relaxation potentially discriminate different mechanisms which contribute to slowing of relaxation in fatigue, a point which would be missed if a single method of measurement of relaxation was employed.
A new conception of dynamic or static muscular work tests is presented. The authors define the critical power of a muscular work from the notions of maximum work and maximum time of work. The work capacity is then considered in the case of dynamic work, and of continuous or intermittent static work. From the data presented it is possible to define the maximum amount of work that can be performed in a given time as well as the conditions of work performed without fatigue. (French & German summaries) (22 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
To determine if training status directly impacted the response to postactivation potentiation, athletes in sports requiring explosive strength (ATH; n = 7) were compared to recreationally trained (RT; n = 17) individuals. Over the course of 4 sessions, subjects performed rebound and concentric-only jump squats with 30%, 50%, and 70% 1 RM loads. Jump squats were performed 5 minutes and 18.5 minutes following control or heavy load warm-ups. Heavy load warm-up consisted of 5 sets of 1 repetition at 90% 1 RM back squat. Jump squat performance was assessed with a force platform and position transducer. Heavy load warm-up did not have an effect on the subjects as a single sample. However, when percent potentiation was compared between ATH and RT groups, force and power parameters were significantly greater for ATH (p < 0.05). Postactivation potentiation may be a viable method of acutely enhancing explosive strength performance in athletic but not recreationally trained individuals.
(C) 2003 National Strength and Conditioning Association
In an effort to assess the effects of environmental heat stress on muscle metabolism during exercise, 6 men performed work in the heat (T
db = 41° C, RH = 15%) and cold (T
db = 9° C, RH = 55%). Exercise consisted of three 15-min cycling bouts at 70 to 85%, with 10-min rest between each. Muscle biopsies obtained from the vastus lateralis before and after each work bout were analyzed for glycogen and triglyceride content. Venous blood samples drawn before and after exercise were assayed for lactate, glucose, free fatty acids, hemoglobin, and hematocrit. Oxygen uptake, heart rates and rectal temperatures were all significantly higher during exercise in the heat. Blood lactate concentration was roughly twice as great during the heat experiments as that measured in the 9° C environment. Muscle glycogen utilization per 60 min was significantly greater in the heat (−74 m moles/kg-wet muscle) as compared to the cold exercise (−42 m moles/kg-wet muscle.) On the average, muscle triglyceride declined 23% during exercise in the cold and 11% in the heat. The findings of an enhanced glycolysis during exercise in the heat is compatible with earlier studies which demonstrate a decreased availability of oxygen due to a reduction in muscle blood flow.
The effect of changing muscle temperature on performance of short term dynamic exercise in man was studied. Four subjects performed 20 s maximal sprint efforts at a constant pedalling rate of 95 crank rev.min-1 on an isokinetic cycle ergometer under four temperature conditions: from rest at room temperature; and following 45 min of leg immersion in water baths at 44; 18; and 12 degrees C. Muscle temperature (Tm) at 3 cm depth was respectively 36.6, 39.3, 31.9 and 29.0 degrees C. After warming the legs in a 44 degrees C water bath there was an increase of approximately 11% in maximal peak force and power (PPmax) compared with normal rest while cooling the legs in 18 and 12 degrees C water baths resulted in reductions of approximately 12% and 21% respectively. Associated with an increased maximal peak power at higher Tm was an increased rate of fatigue. Two subjects performed isokinetic cycling at three different pedalling rates (54, 95 and 140 rev.min-1) demonstrating that the magnitude of the temperature effect was velocity dependent: At the slowest pedalling rate the effect of warming the muscle was to increase PPmax by approximately 2% per degree C but at the highest speed this increased to approximately 10% per degree C.
The physiological properties of contraction-induced phosphate incorporation into the phosphorylatable light chain (P-light chain) of myosin were examined in fast-twitch white, fast-twitch red, and slow-twitch skeletal muscles in situ. Neural stimulation of rat gastrocnemius muscles between 0.5 and 100 Hz produced an increase in the phosphate content of the P-light chain from the white portion of the muscle, and the rate of P-light chain phosphorylation was frequency dependent. The extent of phosphorylation of P-light chain from the fast-twitch red portion of the gastrocnemius muscle was less. In contrast to fast-twitch skeletal muscle, only high-frequency stimulation (30-100 Hz) produced a small increase in the phosphate content of P-light chain from the slow-twitch soleus muscle. Fast white muscle contained 2.2 and 3.5 times more myosin light chain kinase activity than did the fast red and slow muscle, respectively. The rate of P-light chain dephosphorylation was four times faster in slow muscle than in fast white muscle. Thus the greater extent of phosphorylation of P-light chain in fast-twitch white skeletal muscle fibers may be due in part to the presence of more kinase and less phosphatase activities. Isometric twitch tension potentiation was correlated to the extent of phosphorylation of P-light chain from fast white muscle. The physiological consequences of P-light chain phosphorylation are likely to be of greatest importance in fast-twitch white muscle.
Monod and Scherrer (1965) showed that there was a linear relation between the maximal work and the maximal time over which the work was performed until the onset of local muscular exhaustion. This linear relation could be expressed by the equation: Wlim =a+bTlim, where maximal work (Wlim) was thought to result from the use of an energy reserve (a) and an energy reconstitution whose maximal rate was (b) We have extended this concept to total body work (bicycle ergometer). Eight male and eight female college students underwent exercise tests at 400, 350, 300,275 and 300,250,200,175 W respectively, to the onset of fatigue. The regression analysis revealed that the linearity of individual plots was found to be 0-982