20-m Sprint Test Research Articles

Effects of Velocity Loss During Resistance Training on Performance in Professional Soccer Players

To analyze the effects of 2 resistance-training (RT) programs that used the same relative loading but different repetition volume, using the velocity loss during the set as the independent variable: 15% (VL15) vs 30% (VL30). Sixteen professional soccer players with RT experience (age 23.8 ± 3.5 y, body mass 75.5 ± 8.6 kg) were randomly assigned to 2 groups, VL15 (n = 8) or VL30 (n = 8), that followed a 6-wk (18-session) velocity-based squat-training program. Repetition velocity was monitored in all sessions. Assessments performed before (Pre) and after training (Post) included estimated 1-repetition maximum (1RM) and change in average mean propulsive velocity (AMPV) against absolute loads common to Pre and Post tests, countermovement jump (CMJ), 30-m sprint (T30), and Yo-Yo Intermittent Recovery Test (YIRT). Null-hypothesis significance testing and magnitude-based-inference statistical analyses were performed. VL15 obtained greater gains in CMJ height than VL30 (P < .05), with no significant differences between groups for the remaining variables. VL15 showed a likely/possibly positive effect on 1RM (91/9/0%), AMPV (73/25/2%), and CMJ (87/12/1%), whereas VL30 showed possibly/unclear positive effects on 1RM (65/33/2%) and AMPV (46/36/18%) and possibly negative effects on CMJ (4/38/57%). The effects on T30 performance were unclear/unlikely for both groups, whereas both groups showed most likely/likely positive effects on YIRT. A velocity-based RT program characterized by a low degree of fatigue (15% velocity loss in each set) is effective to induce improvements in neuromuscular performance in professional soccer players with previous RT experience.

Change of direction ability in young elite soccer players: determining factors vary with angle variation.

The ability to change direction is considered of paramount importance in team sports. Currently there is a lack of consensus regarding the most important physical factors that determine change of direction (COD) ability. Therefore, the aim of this study was to examine the relationship between COD ability and targeted selected physical attributes of sprinting, isometric strength and explosive power. Thirty-one young elite soccer players (mean±SD, age =17.4±0.6 years, height =177±0.5 cm; leg length =96.9±3.3 cm, body-mass =69.0±6.2 kg) were recruited. A total of eight COD tasks consisting of; a 5-m sprint then a COD of 45°, 90°, 135° or 180° followed by another 5m sprint were performed using dominant (DL) and non-dominant legs (NDL). Physical tests including a 10-m Straight-Line Sprint Test, 12 lower limb isometric strength tests, and jumping tests including: 1) five alternate Leg Jump Test; 2) triple hop distance (DL and NDL); and 3) Standing Broad Jump Test were performed. Stepwise multiple regression analysis showed that the physical attributes explained between 30% and 74% of the variance of the COD performance. Furthermore, these physical attributes were dependent upon COD angle and direction. The affecting variables of the COD performance differ according to the angle of COD and the leg used to turn. Moreover, isometric strength of the lower-limb muscles represented a major determinant factor of the COD-ability. Consequently, physical fitness coaches should include isometric muscle strengthening exercises in addition to traditional dynamic muscle strength exercises. Moreover, they should implement specific lower limb strength exercises depending on players' deficit in each COD's angles.

THE RELATIVE AGE EFFECTS IN YOUNG SOCCER PLAYERS AND IT RELATIONS WITH THE COMPETITIVE LEVEL, SPECIFIC POSITION, MORPHOLOGICAL CHARACTERISTICS, PHYSICAL FITNESS AND TECHNICAL SKILLS

This study investigated the relative age effects (RAE) in young soccer players and it relations to morphological, technical and physical variables, in a sample of 267 male players from U17 and U19 categories. Our results showed significant differences by age quartiles in relation to the competition level (U17), field positions (U17 and U19) and the 30m sprint test (U19). In summary, no significant associations were identified on morphological characteristics, physical fitness and technical skills in relation to the RAE.

Positive effects on bone mineralisation and muscular fitness after 10 months of intense school-based physical training for children aged 8–10 years: the FIT FIRST randomised controlled trial

ObjectivesWe investigated whether musculoskeletal fitness of school children aged 8–10 years was affected by frequent intense PE sessions.Design and participants295 Danish school children aged 8–10 years were cluster randomised to...

Faster Futsal Players Perceive Higher Training Loads and Present Greater Decreases in Sprinting Speed During the Preseason.

The aims of this study were to assess the speed-power characteristics of professional futsal players before and after a 9-week preseason and to explore possible relationships with internal training loads. Ten under-20 professional Brazilian futsal players performed unloaded (squat jump [SJ] and countermovement jump [CMJ]) and loaded (jump squat [JS]) jumps and a 20-m sprint test before and after the preseason. Weekly training loads as measured by session rating of perceived exertion (s-RPE) varied between 2,179 and 5,519 a.u. The magnitude-based inference statistics revealed that performance in the SJ, CMJ, and 20-m sprint very likely decreased (effect size [ES] = -0.64, -0.49, and -0.92, respectively), whereas mean propulsive power in the JS likely increased (ES = 0.42) in response to the preseason. The Pearson coefficient of correlation between velocity in the 20 m sprint test and s-RPE during the first 2 weeks of training was 0.66 (p ≤ 0.05) while no significant correlation was detected between total s-RPE (i.e., 9 weeks) and changes in the power-speed tests. The baseline 20-m sprint velocity was very largely and inversely (r = -0.90) correlated with the change in the 20-m sprint performance. In conclusion, futsal preseason training leads to impaired unloaded vertical jump and sprint test performance, with speed decreasing more in faster than slower players. In addition, because of the large correlation between baseline sprint ability and s-RPE, coaches are advised to assess sprinting performance at the beginning of the preseason to finely adjust the training stimuli to each athlete.

Seasonal Training Load Distribution of Professional Futsal Players: Effects on Physical Fitness, Muscle Damage and Hormonal Status.

The aims of the present study were to describe the training load (TL) distribution of a professional futsal team and verify its subsequent effects on physical performance, muscle damage, and hormonal status. Twelve male professional futsal players (24.3 ± 4.7 years old; 75.5 ± 7.7 kg; and 173.4 ± 4.5 cm) participated in this study. A training program of 22 weeks (6 weeks of pre-season and 16 weeks of in-season) was analyzed. The session rating of perceived exertion method was used to monitor TLs. Physical tests (PTs; countermovement jump (CMJ), 5- and 20-m sprint, T-test, and multistage 20-m shuttle-run tests) were performed 4 times throughout the season (PT1-PT4). Blood sample (BS) collection (Creatine kinase [CK], testosterone, and cortisol) was performed in 7 occasions (BS1-BS7). TLs were higher in pre-season compared to in-season (p < 0.001). Countermovement jumps (CMJs) and 5- and 20-m performances were better in PT3 (CMJ: 0/23/77, 5-m: 0/3/97, and 20-m: 0/1/99) and PT4 (CMJ: 0/8/92, 5- and 20-m: 0/0/100) than in PT1; T-test performance and V[Combining Dot Above]O2max was better in all moments compared with those of PT1 (0/0/100). Higher CK concentration (p = 0.03) and testosterone to cortisol (T:C) ratio values (p = 0.02) were detected in BS2 vs. BS1. An increase in C (p = 0.007) and a decrease in T:C ratio (p = 0.003) was observed from BS4 to BS5. The training program demonstrated higher TLs during the periods with low incidence of matches, emphasis on endurance and strength training during pre-season, speed and power training throughout in-season. This TL organization provides sufficient stimulus for appropriate physical fitness development in professional futsal players, without causing negative disturbances.

Effects of Induced Volitional Fatigue on Sprint and Jump Performance in Paralympic Athletes with Cerebral Palsy.

This study investigated performance, neuromuscular characteristics, and fatigue in Paralympic athletes with cerebral palsy (CP) during a maximal explosive performance trial, compared with well-trained, sprint-specific able-bodied athletes. Six Paralympic athletes with hemiplegic CP and 12 able-bodied athletes performed one 40-m sprint test (in seconds) and Vertical Jump Tests off both legs (in centimeters), the affected leg individually (in centimeters), and the nonaffected leg individually (in centimeters) before and after an adapted Multistage Shuttle Run Test to exhaustion. Electromyography of five bilateral muscles was measured for mean amplitude (percentage maximum activation). The 40-m sprint test, Vertical Jump Test off both legs, and Vertical Jump Test off the affected leg were significantly compromised in the CP group, whereas the Vertical Jump Test off the nonaffected leg was similar between groups (P < 0.05). Both groups fatigued similarly in performance and electromyography. Affected side electromyography was higher than nonaffected electromyography in the Vertical Jump Test off both legs and Vertical Jump Test off the affected leg in both groups. The similarity in fatigue between CP and able-bodied groups confirms that Paralympic athletes with CP may have overcome deficits associated with CP documented in sedentary children. The identified asymmetry may assist with a deeper understanding of performance deficits in CP, as it is indicated that activity generated by both legs is performed toward the capacity of the affected leg.

Physiological and Neuromuscular Response to a Simulated Sprint-Distance Triathlon: Effect of Age Differences and Ability Level.

This study aimed to describe the acute impact of a simulated sprint-distance triathlon at physiological and neuromuscular levels and to determine whether age and athletic performance influenced the response in triathletes. Nineteen triathletes performed a sprint-distance triathlon under simulated conditions. Cardiovascular response was monitored during the race. Rate of perceived exertion along with muscular performance parameters (countermovement jump [CMJ], squat jump [SJ], and handgrip strength test [HS]) were tested at pre- and posttest and during every transition, while a 20-m sprint test (S20m) was performed before and after the race. Blood lactate was recorded postrace. A repeated measures analysis of variance showed that the neuromuscular response-in terms of CMJ, SJ, and HS-was unchanged (p ≥ 0.05), while S20m performance was impaired at posttest (p < 0.001). A linear regression analysis showed that ΔCMJ predicted the overall race time (R = 0.226; p = 0.046). In addition, 2 cluster analyses (k-means) were performed by grouping according to athletic performance and age. Between-group comparison showed no significant differences in the impact of the race at either the physiological or the neuromuscular level. The results showed that muscular performance parameters were not impaired throughout the race despite high levels of fatigue reported. However, despite maintaining initial levels of muscle force after the race, the fatigue-induced changes in S20m were significant, which could reinforce the need to train sprint ability in endurance athletes. Finally, despite the differences in ability level or in age, the acute physiological and neuromuscular responses to a simulated sprint-distance triathlon were similar.

The Effects of a 6-Week Strength Training on Critical Velocity, Anaerobic Running Distance, 30-M Sprint and Yo-Yo Intermittent Running Test Performances in Male Soccer Players.

The objectives of this study were to examine the effects of a moderate intensity strength training on changes in critical velocity (CV), anaerobic running distance (D'), sprint performance and Yo-Yo intermittent running test (Yo-Yo IR1) performances. Methods: two recreational soccer teams were divided in a soccer training only group (SO; n = 13) and a strength and soccer training group (ST; n = 13). Both groups were tested for values of CV, D', Yo-Yo IR1 distance and 30-m sprint time on two separate occasions (pre and post intervention). The ST group performed a concurrent 6-week upper and lower body strength and soccer training, whilst the SO group performed a soccer only training. Results: after the re-test of all variables, the ST demonstrated significant improvements for both, YoYo IR1 distance (p = 0.002) and CV values (p<0.001) with no significant changes in the SO group. 30-m sprint performance were slightly improved in the ST group with significantly decreased performance times identified in the SO group (p<0.001). Values for D' were slightly reduced in both groups (ST -44.5 m, 95% CI = -90.6 to 1.6; SO -42.6 m, 95% CI = -88.7 to 3.5). Conclusions: combining a 6-week moderate strength training with soccer training significantly improves CV, Yo-Yo IR1 whilst moderately improving 30-m sprint performances in non-previously resistance trained male soccer players. Critical Velocity can be recommended to coaches as an additional valid testing tool in soccer.

Influence of Age, Maturity, and Body Size on the Spatiotemporal Determinants of Maximal Sprint Speed in Boys.

Meyers, RW, Oliver, JL, Hughes, MG, Lloyd, RS, and Cronin, JB. Influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. J Strength Cond Res 31(4): 1009-1016, 2017-The aim of this study was to investigate the influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. Three-hundred and seventy-five boys (age: 13.0 ± 1.3 years) completed a 30-m sprint test, during which maximal speed, step length, step frequency, contact time, and flight time were recorded using an optical measurement system. Body mass, height, leg length, and a maturity offset represented somatic variables. Step frequency accounted for the highest proportion of variance in speed (∼58%) in the pre-peak height velocity (pre-PHV) group, whereas step length explained the majority of the variance in speed (∼54%) in the post-PHV group. In the pre-PHV group, mass was negatively related to speed, step length, step frequency, and contact time; however, measures of stature had a positive influence on speed and step length yet a negative influence on step frequency. Speed and step length were also negatively influence by mass in the post-PHV group, whereas leg length continued to positively influence step length. The results highlighted that pre-PHV boys may be deemed step frequency reliant, whereas those post-PHV boys may be marginally step length reliant. Furthermore, the negative influence of body mass, both pre-PHV and post-PHV, suggests that training to optimize sprint performance in youth should include methods such as plyometric and strength training, where a high neuromuscular focus and the development force production relative to body weight are key foci.

Influence of physical fitness on cardio-metabolic risk factors in European children. The IDEFICS study.

The aim of the study was to assess the associations of individual and combined physical fitness components with single and clustering of cardio-metabolic risk factors in children. This 2-year longitudinal study included a total of 1635 European children aged 6-11 years. The test battery included cardio-respiratory fitness (20-m shuttle run test), upper-limb strength (handgrip test), lower-limb strength (standing long jump test), balance (flamingo test), flexibility (back-saver sit-and-reach) and speed (40-m sprint test). Metabolic risk was assessed through z-score standardization using four components: waist circumference, blood pressure (systolic and diastolic), blood lipids (triglycerides and high-density lipoprotein) and insulin resistance (homeostasis model assessment). Mixed model regression analyses were adjusted for sex, age, parental education, sugar and fat intake, and body mass index. Physical fitness was inversely associated with clustered metabolic risk (P<0.001). All coefficients showed a higher clustered metabolic risk with lower physical fitness, except for upper-limb strength (β=0.057; P=0.002) where the opposite association was found. Cardio-respiratory fitness (β=-0.124; P<0.001) and lower-limb strength (β=-0.076; P=0.002) were the most important longitudinal determinants. The effects of cardio-respiratory fitness were even independent of the amount of vigorous-to-moderate activity (β=-0.059; P=0.029). Among all the metabolic risk components, blood pressure seemed not well predicted by physical fitness, while waist circumference, blood lipids and insulin resistance all seemed significantly predicted by physical fitness. Poor physical fitness in children is associated with the development of cardio-metabolic risk factors. Based on our results, this risk might be modified by improving mainly cardio-respiratory fitness and lower-limb muscular strength.

Effect of Three Protocols of Warming up Involving Stretching on the Kinematic Performance of Horizontal Jumping, Agility and Speed for Soccer Players

The aim of this study is to investigate the effect of three different protocols of stretching on the kinematic performance of horizontal jumping, Agility and speed for soccer players. The first protocol is doing ballistic stretching then static stretching exercises (BS-SS). The second protocol is doing static stretching then ballistic stretching exercises (SS-BS). The third protocol is doing soccer passing drills (SPD) for 10 minutes without stretching. The three protocols were applied after 5 minutes of running activities. Dependent variables included a horizontal jump, agility run, and 30-m sprint tests. Also speed, acceleration, and steps frequency were analyzed. This study was applied on 23 trained male student-athletes aged (20+ 0.4 years). The (SS-BS) condition (2.247 + 0.096 m) showed significant differences (p < 0.01) for longer distance than the (BS-SS) condition (2.165 + 0.124) and also than the (SPD) condition (2.197 + 0.110 m) in the horizontal jump test. The (SS-BS) condition (3.544 + 0.247 second) also showed significant differences (p < 0.01) in the flying 30m sprint test for faster times than the (BS-SS) condition (3.858 + 0.288 second) and also than the third condition (SPD) (4.050 + 0.193 second) . The (SPD) condition showed significant differences (p < 0.01) in agility test for faster time than both the (BS-SS) (11.533 + 0.485) and (SS-BS) (11.676 + 0.530) conditions. Depending on the study results and previous studies, (SS-BS) which may be practiced before high intensity activities in trained athletes if preceded by moderate intensity running activities is recommended.

Effects of cluster vs. traditional plyometric training sets on maximal-intensity exercise performance

ObjectiveThe aim of this study was to compare the effects of 6-week cluster versus traditional plyometric training sets on jumping ability, sprint and agility performance. Materials and methodsThirteen college students were assigned to a cluster sets group (N=6) or traditional sets group (N=7). Both training groups completed the same training program. The traditional group completed five sets of 20 repetitions with 2min of rest between sets each session, while the cluster group completed five sets of 20 [2×10] repetitions with 30/90-s rest each session. Subjects were evaluated for countermovement jump (CMJ), standing long jump (SLJ), t test, 20-m and 40-m sprint test performance before and after the intervention. ResultsBoth groups had similar improvements (P<0.05) in CMJ, SLJ, t test, 20-m, and 40-m sprint. However, the magnitude of improvement in CMJ, SLJ and t test was greater for the cluster group (effect size [ES]=1.24, 0.81 and 1.38, respectively) compared to the traditional group (ES=0.84, 0.60 and 0.55). Conversely, the magnitude of improvement in 20-m and 40-m sprint test was greater for the traditional group (ES=1.59 and 0.96, respectively) compared to the cluster group (ES=0.94 and 0.75, respectively). ConclusionsAlthough both plyometric training methods improved lower body maximal-intensity exercise performance, the traditional sets methods resulted in greater adaptations in sprint performance, while the cluster sets method resulted in greater jump and agility adaptations.

The effect of time of day on short-term maximal performance in obese and non-obese young men

The purpose of this study was to examine time-of-day effects on short-term performance in obese young men. In a balanced study design, 30 boys were divided into two groups: obese (OG; n = 15) and non-obese (CG; n = 15) groups. Both groups performed anaerobic tests of strength and power (squat-Jump, SJ; counter-movement jump, CMJ; 10-m sprint; and 30-m sprint) at 08:00 and 17:00 h on separate days. The results showed morning–evening differences in all variables in CG, with significant increases at 17:00 h (around the time of peak temperature) in comparison with 08:00 h (p < 0.01) for OG. However, such morning-evening differences were not found in the OG, except for the 30-m sprint. Obesity affects the diurnal variation on performances of 30-m sprint with a significant decrease in the evening for OG of 1.23% (p < 0.01). A correlation between anaerobic performance and oral temperature was observed only in the 30-m sprint test. In conclusion, the findings of the present study indicated that obesity is a problem that can affect circadian rhythms and performance in obese young men; therefore, preventing childhood obesity should become a top priority in efforts to improve performance and health.

Influence of Test Distance on Change of Direction Speed Test Results.

This study assessed the relationships between linear running velocity and change of direction (CoD) ability and how assessing CoD ability over distances ≤5 m influences test reliability. Participants (n = 15) from amateur rugby league teams performed 3 trials of a 20-m sprint test (light gates at 5, 10, and 20 m) and 6 trials of the 5-0-5 agility test. Twelve participants repeated the 5-0-5 test several weeks later. A three-dimensional motion capture system (250 Hz) was used to track the center of mass at 0.3, 0.5, and 1.0 m either side of the turn and identify specific CoD phase times. Pearson's correlations showed strong significant relationships between the 5-0-5 time and 5-m (r = 0.89, p < 0.001), 10-m (r = 0.91, p < 0.001), and 20-m sprint times (r = 0.93, p < 0.001). However, the strength of these relationships decreased (r < 0.65, p > 0.05) when CoD ability was measured over distances less than 0.5 m. Analysis of coefficient of variation (CV%) data indicated that the 5-0-5 test had high intratest (CV% = 2.8) and intertest reliability (CV% = 1.3), with these data decreasing for distances less than 1 m (CV% = 3.5-6.9). Specific movement phase times were the least reliable measures of CoD ability (CV% = 4.7-53.6). Results suggest a bias between high-speed linear running ability and 5-0-5 time. However, an effective compromise can be found between test reliability and the external validity by assessing CoD ability over 1 m. Findings indicate that the current practice of assessing CoD ability over large distances in questionable.

Relationship between vertical and horizontal jump variables and muscular performance in athletes.

This study investigated the relationship between vertical and horizontal measures in bilateral and unilateral countermovement jump, drop jump and squat jump (SJ), and sprinting speed and muscle architecture of both the vastus lateralis and gastrocnemius. Subjects (n = 17) completed a 30-m sprint test, muscle stiffness test; ultrasound measures, and a jump testing session. Measures of horizontal peak and mean force, in both bilateral and unilateral jumps, tended to have greater relationships to sprint speeds (R = 0.132-0.576) than peak and mean force in the vertical plane (R = 0.008-0.504). Vertical velocity variables also showed some large and very large correlations to sprint speed (R = 0.062-0.635). Unilateral measures of velocity tended to have larger correlations to sprint performance than their bilateral counterparts across all jump types and peak and mean velocity in SJ showed large and very large correlations to sprint speed (bilateral R = 0.227-0.635; unilateral 0.393-0.574). Few large correlations were shown between muscle stiffness measures of muscle architecture and kinetic and kinematic variables in either vertical or horizontal jumps. The present findings suggest that sport scientists and strength and conditioning practitioners concerned with the prognostic value of kinetic variables to functional movements such as sprint speed should also use horizontal jumps in addition to vertical jumps in testing and training.

청소년 남성 단거리 육상 선수의 30m 스프린트 기록 차이가 하지 근력과 점프 수행에 미치는 영향

The purpose of this study was to effect of lower extremity strength and jump performance for difference of 30m sprint record on short distance youth athletes. For this study, 49 subjects were measured 30m sprint test. Based on the result of 30m sprint, 30% upper rankers are assigned to superior athletes group (SAG, n=15), and 30% lower rankers are assigned to inferior athletes group (IAG, n=15). Then, hip, knee and ankle joint isokinetic strength were tested at each angular velocity (hip joint 30°/sec; knee joint 30°/sec; ankle joint 60°/ sec). And both groups measured squat jump high and counter movement jump high. As a result, peak torque of hip right/left extensor, knee right flexor/extensor, ankle right/left plantarflexor in SAG was significantly higher than IAG. Average power of hip right flexor, hip right/left extensor, knee right/left flexor, knee right/ left extensor, ankle right/left plantarflexor in SAG was significantly higher than IAG. Both squat jump high and counter movement jump high in SAG was significantly higher than IAG. In conclusion, 30m sprint record on short distance youth athletes were more important extensor than flexor, right than left in lower strength. And elastic movement with full rage of motion in lower has supported greatly in athletic performance.

Association between Leg Power and Sprinting Technique with 20-m Sprint Performance in Elite Junior Australian Football Players

The main purpose of this study was to determine the association between leg power and sprint technique with 20-m sprint performance. Seventy-seven elite junior Australian Rules football players were assessed on a 20-m sprint test, a countermovement jump (CMJ) and a two bound test, and on a new method of quantifying sprint technique from simple video recordings. Technique assessment involved rating 14 points on a scale from 1–5. Players were median-split into faster and slower groups based on their 20-m times, and they were compared for differences in leg power and technique. The faster group was significantly better (p&lt;0.05) in the two-bound test (5.2%) and the technique score (8.2%), but not in the CMJ (p&gt;0.05). A multiple regression indicated that the two-bound test and technique accounted for 37.7% of the variance associated with the 20-m sprint time (p&lt;0.05). It was concluded that the technique assessment tool captured some important characteristics of 20-m sprint performance and could potentially be used to profile or monitor athletes. Further the two-bound test is a more relevant test for developing athletes because of its specificity to sprinting, compared to the CMJ.

The effect of 8-week plyometric training on leg power, jump and sprint performance in female soccer players.

The aim of this study was to determine the effect of 8-week plyometric training (PT) on the leg power and jump and sprint performance in female soccer players. Eighteen female soccer players from Women Second League (age = 18.2 ± 2.3 years, height = 161.3 ± 5.4 cm, body mass = 56.6 ± 7.2 kg) were randomly assigned to control (n = 9) and plyometric (n = 9) groups. Both groups continued together with regular technical and tactical soccer training for 4 days a week. Additionally, the plyometric group underwent PT for 8 weeks, 1 day per week, 60-minute session duration. During the 8-week period, the control group was hindered from any additional conditioning training. All players' jumps (triple hop, countermovement jump, and standing broad jump), running speed (20 m), and peak power were evaluated before and after 8 weeks. No significant difference was found between the groups at pretest variables (p > 0.05). Significant improvements were found in the posttest of both the groups (p ≤ 0.05), except for 20-m sprint test in the control group (p > 0.05). Triple hop distance, countermovement jump, standing broad jump, peak power, and 20-m sprint test values were all significantly improved in the plyometric group, compared with the control group (p ≤ 0.05). We concluded that short duration PT is an improved important component of athletic performance in female soccer players. The results indicate that safe, effective, and alternative PT can be useful to strength and conditioning coaches, especially during competition season where less time is available for training.

Effects of Weighted Sled Towing With Heavy Versus Light Load on Sprint Acceleration Ability

Weighted sled towing is used by athletes to improve sprint acceleration ability. The typical coaching recommendation is to use relatively light loads, as excessively heavy loads are hypothesized to disrupt running mechanics and be detrimental to sprint performance. However, this coaching recommendation has not been empirically tested. This study compared the effects of weighted sled towing with 2 different external loads on sprint acceleration ability. Twenty-one physically active men were randomly allocated to heavy- (n = 10) or light-load weighted sled towing (n = 11) groups. All subjects participated in 2 training sessions per week for 8 weeks. The subjects in the heavy and light groups performed weighted sled towing using external loads that reduced sprint velocity by approximately 30 and 10%, respectively. Before and after the training, the subjects performed a 10-m sprint test, in which split time was measured at 5 and 10 m from the start. The heavy group significantly improved both the 5- and 10-m sprint time by 5.7 ± 5.7 and 5.0 ± 3.5%, respectively (P < 0.05), whereas only 10-m sprint time was improved significantly by 3.0 ± 3.5% (P < 0.05) in the light group. No significant differences were found between the groups in the changes in 5-m and 10-m sprint time from pre- to posttraining. These results question the notion that training loads that induce greater than 10% reduction in sprint velocity would negatively affect sprint performance and point out the potential benefit of using a heavier load for weighted sled towing.