Are changes in maximal squat strength during preseason training reflected in changes in sprint performance in rugby league players?

Because previous research has shown a relationship between maximal squat strength and sprint performance, this study aimed to determine if changes in maximal squat strength were reflected in sprint performance. Nineteen professional rugby league players (height = 1.84 ± 0.06 m, body mass [BM] = 96.2 ± 11.11 kg, 1 repetition maximum [1RM] = 170.6 ± 21.4 kg, 1RM/BM = 1.78 ± 0.27) conducted 1RM squat and sprint tests (5, 10, and 20 m) before and immediately after 8 weeks of preseason strength (4-week Mesocycle) and power (4-week Mesocycle) training. Both absolute and relative squat strength values showed significant increases after the training period (pre: 170.6 ± 21.4 kg, post: 200.8 ± 19.0 kg, p < 0.001; 1RM/BM pre: 1.78 ± 0.27 kg·kg(-1), post: 2.05 ± 0.21 kg·kg(-1), p < 0.001; respectively), which was reflected in the significantly faster sprint performances over 5 m (pre: 1.05 ± 0.06 seconds, post: 0.97 ± 0.05 seconds, p < 0.001), 10 m (pre: 1.78 ± 0.07 seconds, post: 1.65 ± 0.08 seconds, p < 0.001), and 20 m (pre: 3.03 ± 0.09 seconds, post: 2.85 ± 0.11 seconds, p < 0.001) posttraining. Whether the improvements in sprint performance came as a direct consequence of increased strength or whether both are a function of the strength and power mesocycles incorporated into the players' preseason training is unclear. It is likely that the increased force production, noted via the increased squat performance, contributed to the improved sprint performances. To increase short sprint performance, athletes should, therefore, consider increasing maximal strength via the back squat.     

Coordination of soccer players during preseason training

This study aimed to verify whether coordination improves as a result of a preseason soccer training. During 5 experimental sessions (days 1, 6, 11, 15, and 19), 16 semiprofessional male soccer players (22.0 ± 3.6 years) were administered 3 specific soccer tests (speed dribbling, shooting a dead ball, and shooting from a pass) and an interlimb coordination test (total duration of a trial: 60 seconds), consisting of isodirectional and nonisodirectional synchronized (1:1 ratio) hand and foot flexions and extensions at an increasing velocity of execution (80, 120, and 180 b·min(-1)). Furthermore, subjective ratings were monitored to assess the recovery state (RestQ) of the players, their perceived exertion (rating of perceived exertion [RPE]) for the whole body, and the perceived muscle pain (rating of muscle pain [RMP]) for the lower limbs and the internal training load by means of the session-RPE method. The ratios between post and pretraining RPE and RMP increased only during the first 2 experimental sessions and decreased after the second week of the training camp (p = 0.001). The Rest-Q showed increases (p < 0.05) for general stress, conflict/pressure, social recovery, and being in shape dimensions. Conversely, decreases (p < 0.05) were observed for social stress, fatigue, physical complaints dimensions. Throughout the preseason, the players improved their speed dribbling (p = 0.03), Shooting from a Pass (p = 0.02), and interlimb coordination (p < 0.0001) performances. These coordination tests succeeded in discriminating coordination in soccer players and could integrate field test batteries during the whole soccer season, because they were easily and inexpensively administrable by coaches.     

Complex training in ice hockey: the effects of a heavy resisted sprint on subsequent ice-hockey sprint performance

The aim of the study was to investigate the acute effect of a heavy resisted sprint when used as a preload exercise to enhance subsequent 25-m on-ice sprint performance. Eleven competitive ice-hockey players (mean ± SD: Age = 22.09 ± 3.05 years; Body Mass = 83.47 ± 11.7 kg; Height = 1.794 ± 0.060 m) from the English National League participated in a same-subject repeated-measures design, involving 2 experimental conditions. During condition 1, participants performed a 10-second heavy resisted sprint on ice. Condition 2 was a control, where participants rested. An electronically timed 25-m sprint on ice was performed before and 4 minutes after each condition. The results indicated no significant difference (p = 0.176) between pre (3.940 + 0.258 seconds) and post (3.954 + 0.261 seconds) sprint times in the control condition. The intervention condition, however, demonstrated a significant 2.6% decrease in times (p = 0.02) between pre (3.950 + 0.251 seconds) and post (3.859 + 0.288 seconds) test sprints. There was also a significant change (p = 0.002) when compared to the times of the control condition. These findings appear to suggest that the intensity and duration of a single resisted sprint in this study are sufficient to induce an acute (after 4 minutes of rest) improvement in 25-m sprint performance on ice. For those athletes wishing to improve skating speed, heavy resisted sprints on ice may provide a biomechanically suitable exercise for inducing potentiation before speed training drills.     

The effect of 40-m repeated sprint training on maximum sprinting speed, repeated sprint speed endurance, vertical jump, and aerobic capacity in young elite male soccer players

The purpose of this study was to examine the effect of 10 weeks' 40-m repeated sprint training program that does not involve strength training on sprinting speed and repeated sprint speed on young elite soccer players. Twenty young well-trained elite male soccer players of age (±SD) 16.4 (±0.9) years, body mass 67.2 (±9.1) kg, and stature 176.3 (±7.4) cm volunteered to participate in this study. All participants were tested on 40-m running speed, 10 × 40-m repeated sprint speed, 20-m acceleration speed, 20-m top speed, countermovement jump (CMJ), and aerobic endurance (beep test). Participants were divided into training group (TG) (n = 10) and control group (CG) (n = 10). The study was conducted in the precompetition phase of the training program for the participants and ended 13 weeks before the start of the season; the duration of the precompetition period was 26 weeks. The TG followed a Periodized repeated sprint training program once a week. The training program consisted of running 40 m with different intensities and duration from week to week. Within-group results indicate that TG had a statistically marked improvement in their performance from pre to posttest in 40-m maximum sprint (-0.06 seconds), 10 × 40-m repeated sprint speed (-0.12 seconds), 20- to 40-m top speed (-0.05 seconds), and CMJ (2.7 cm). The CG showed only a statistically notable improvement from pre to posttest in 10 × 40-m repeated sprint speed (-0.06 seconds). Between-group differences showed a statistically marked improvement for the TG over the CG in 10 × 40-m repeated sprint speed (-0.07 seconds) and 20- to 40-m top speed (-0.05 seconds), but the effect of the improvement was moderate. The results further indicate that a weekly training with repeated sprint gave a moderate but not statistically marked improvement in 40-m sprinting, CMJ, and beep test. The results of this study indicate that the repeated sprint program had a positive effect on several of the parameters tested. However, because the sample size in this study is 20 participants, the results are valid only for those who took part in this study. Therefore, we advice to use repeated sprint training similar to the one in this study only in periods where the players have no speed training included in their program. Furthermore, the participants in this study should probably trained strength, however, benefits were observed even without strength training is most likely to be caused by the training specificity.     

The relationship between kinematic determinants of jump and sprint performance in division I women soccer players

The purpose of this study was to determine the relationship between measures of unilateral and bilateral jumping performance and 10- and 25-m sprint performance. Fifteen division I women soccer players (height 165 ± 2.44 cm, mass 61.65 ± 7.7 kg, age 20.19 ± 0.91 years) volunteered to participate in this study. The subjects completed a 10- and 25-m sprint test. The following jump kinematic variables were measured using accelerometry: sprint time, step length, step frequency, jump height and distance, contact time, concentric contact time, and flight time (Inform Sport Training Systems, Victoria, BC, Canada). The following jumps were completed in random order: bilateral countermovement vertical jump, bilateral countermovement horizontal jump, bilateral 40-cm drop vertical jump, bilateral 40-cm drop horizontal jump, unilateral countermovement vertical jump (UCV), unilateral countermovement horizontal jump, unilateral 20-cm drop vertical jump (UDV), and unilateral 20-cm drop horizontal jump (UDH). The trial with the best jump height or distance, reactive strength (jump height or distance/total contact time), and flight time to concentric contact time ratio (FT/CCT) was recorded to analyze the relationship between jump kinematics and sprint performance. None of the bilateral jump kinematics significantly correlated with 10- and 25-m sprint time, step length, or step frequency. Right-leg jump height (r = -0.71, p = 0.006, SEE = 0.152 seconds), FT/CCT (r = -0.58, p = 0.04, SEE = 0.176 seconds), and combined right and left-leg jump height (r = -0.61) were significantly correlated with the 25-m sprint time during the UCV. Right-leg FT/CCT was also significantly related to 25-m step length (r = 0.68, p = 0.03, SEE = 0.06 m) during the UDV. The combined right and left leg jump distance to standing height ratio during the UDH significantly correlated (r = -0.58) with 10-m sprint time. In comparison to bilateral jumps, unilateral jumps produced a stronger relationship with sprint performance.     

Effects of speed, agility, quickness training method on power performance in elite soccer players

The purpose of this study was to evaluate the effects of the speed, agility, quickness (SAQ) training method on power performance in soccer players. Soccer players were assigned randomly to 2 groups: experimental group (EG; n = 50) and control group (n = 50). Power performance was assessed by a test of quickness--the 5-m sprint, a test of acceleration--the 10-m sprint, tests of maximal speed--the 20- and the 30-m sprint along with Bosco jump tests--squat jump, countermovement jump (CMJ), maximal CMJ, and continuous jumps performed with legs extended. The initial testing procedure took place at the beginning of the in-season period. The 8-week specific SAQ training program was implemented after which final testing took place. The results of the 2-way analysis of variance indicated that the EG improved significantly (p < 0.05) in 5-m (1.43 vs. 1.39 seconds) and in 10-m (2.15 vs. 2.07 seconds) sprints, and they also improved their jumping performance in countermovement (44.04 vs. 4.48 cm) and continuous jumps (41.08 vs. 41.39 cm) performed with legs extended (p < 0.05). The SAQ training program appears to be an effective way of improving some segments of power performance in young soccer players during the in-season period. Soccer coaches could use this information in the process of planning in-season training. Without proper planning of the SAQ training, soccer players will most likely be confronted with decrease in power performance during in-season period.     

The construct and longitudinal validity of the basketball exercise simulation test

The purpose of this study was to assess the validity of the recently developed Basketball Exercise Simulation Test (BEST). Ten semiprofessional (age, 22.7 ± 6.1 years; height, 189.6 ± 9.5 cm; weight, 86.5 ± 18.7 kg; % body fat, 14.7 ± 3.5%) and 10 recreational (age, 26.6 ± 4.0 years; height, 185.9 ± 7.9 cm; weight, 92.6 ± 8.4 kg; % body fat, 23.8 ± 6.3%) male basketball players volunteered for the study. The participants completed a Yo-Yo Intermittent Recovery Test (Yo-Yo IRT) and BEST trial midway through the playing season. Eight participants (semiprofessional, n = 4; recreational, n = 4) completed an additional Yo-Yo IRT and BEST trial at the end of the playing season. Performance measures from the BEST included sprint decrement (%), mean sprint and circuit time (seconds), and total distance covered (m). Construct validity was calculated using Student's unpaired t-tests to identify the differences in Yo-Yo IRT and BEST performances between playing levels. Longitudinal validity was determined based on the relationship between changes (%) in Yo-Yo IRT1 and BEST performances across the season. Semiprofessional players performed significantly (p < 0.01) better in the Yo-Yo IRT (1,283 ± 62 vs. 636 ± 297 m) and BEST (mean sprint time: 1.45 ± 0.01 vs. 1.65 ± 0.03 seconds; mean circuit time: 18.98 ± 1.79 vs. 22.72 ± 2.01 seconds; sprint decrement: 8.54 ± 0.15 vs. 15.38 ± 0.27%) compared with recreational players. For the group as a whole, a strong relationship was evident between the changes in BEST sprint decrement and changes in Yo-Yo IRT performance (R = -0.815, p = 0.014) across the season. In conclusion, the BEST displayed both discriminative and longitudinal validities and provides a novel match-specific fitness test for basketball players.     

Changes in muscle architecture and performance during a competitive season in female softball players

ABSTRACT: Nimphius, S, McGuigan, MR, and Newton, RU. Changes in muscle architecture and performance during a competitive season in female softball players. J Strength Cond Res 26(10): 2655-2666, 2012-The purpose of this research was (a) to examine the performance changes that occur in elite female softball players during 20 weeks of softball training (that included 14 weeks of periodized resistance training [RT]) and (b) to examine the relationship between percent change (%change) in muscle architecture variables and %change in strength, speed, and change of direction performance. Ten female softball players (age = 18.1 ± 1.6 years, height = 166.5 ± 8.9 cm, weight = 72.4 ± 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower-body strength using a 3 repetition maximum for a predicted 1 repetition maximum (1RM) and peak force, peak velocity (PV), and peak power (PP) were measured during jump squats (JS) unloaded and loaded. In addition, the first base (1B) and the second base (2B) sprint performance, change of direction (505) on dominant (D) and nondominant (ND) sides, aerobic capacity, and muscle architecture characteristics of vastus lateralis (VL) including muscle thickness (MT), fascicle length (FL), and pennation angle (θp) were examined. The testing sessions occurred pre, mid, and post training (total 20 week pre- and in-season training period). Changes over time were analyzed by repeated-measures analysis of variance. The relationship between %change in muscle architecture variables and strength, speed, and change of direction variables from pre to post were assessed by Pearson product-moment correlation coefficient. Significant improvements in PV and PP occurred at all JS loads pre- to mid-testing and pre- to post-testing. Significant increases occurred pre-post in absolute 1RM, relative 1RM, 505 ND, and 2B sprint. The strongest relationships were found between %change in VL MT and 1B sprint (r = -0.80, p = 0.06), %change in VL FL and 2B sprint (r = -0.835, p = 0.02), and %change in relative 1RM and 505 D (r = -0.70, p = 0.04). In conclusion, gains in strength, power, and performance can occur during the season in elite softball players who are also engaged in a periodized RT program. Furthermore, changes in performance measures are associated with changes in muscle architecture.     

Changes evaluated in soccer-specific power endurance either with or without a 10-week,in-season,intermittent, high-intensity training protocol

The purpose of this study was to evaluate changes in soccer-specific power endurance of 34 female high school soccer players throughout a season either with or without an intermittent, high-intensity exercise protocol. Thirty-four female high school soccer players were tested prior to the 2000 fall season and again 10 weeks later. The tests included an abridged 45-minute shuttle test (LIST), hydrostatic weighing, vertical jump, 20-m running-start sprint, and 30-second Wingate test. The experimental group (EG; n = 17, age 16.5 +/- 0.9 years) completed a 10-week in-season plyometric, resistive training, and high-intensity anaerobic program. The control group (n = 17, age 16.3 +/- 1.4 years) completed only traditional aerobic soccer conditioning. Statistical significance was set at alpha < 0.05. The experimental group showed significant improvements in the LIST (EG = delta 394 seconds +/- 124 seconds), 20-m sprint (EG = Delta-0.10 seconds +/- 0.10 seconds), increase in fat-free mass (EG = delta 1.14 kg +/- 1.22 kg), and decreases in fat mass (EG = Delta-1.40 kg +/- 1.47 kg) comparing pre- to postseason. This study indicates that a strength and plyometric program improved power endurance and speed over aerobic training only. Soccer-specific power endurance training may improve match performance and decrease fatigue in young female soccer players.     

A comparison of maximal squat strength and 5-, 10-, and 20-meter sprint times, in athletes and recreationally trained men

The purpose of this study was to identify whether there was a relationship between relative strength during a 1 repetition maximum (1RM) back squat and 5-, 10-, and 20-m sprint performances in both trained athletes and recreationally trained individuals. Professional rugby league players (n = 24) and recreationally trained individuals (n = 20) participated in this investigation. Twenty-meter sprint time and 1RM back squat strength, using free weights, were assessed on different days. There were no significant (p ≥ 0.05) differences between the well-trained and recreationally trained groups for 5-m sprint times. In contrast, the well-trained group's 10- and 20-m sprint times were significantly quicker (p = 0.004; p = 0.002) (1.78 + 0.06 seconds; 3.03 + 0.09 seconds) compared with the recreationally trained group (1.84 + 0.07 seconds; 3.13 + 0.11 seconds). The athletes were significantly stronger (170.63 + 21.43 kg) than the recreationally trained individuals (135.45 + 30.07 kg) (p = 0.01); however, there were no significant differences (p > 0.05) in relative strength between groups (1.78 + 0.27 kg/kg; 1.78 + 0.33 kg/kg, respectively). Significant negative correlations were found between 5-m sprint time and relative squat strength (r = -0.613, power = 0.96, p = 0.004) and between relative squat strength and 10- and 20-m sprint times in the recreationally trained group (r = -0.621, power = 0.51, p = 0.003; r = -0.604, power = 0.53, p = 0.005, respectively). These results, indicating that relative strength, are important for initial sprint acceleration in all athletes but more strongly related to sprint performance over greater distances in recreationally trained individuals.     

Neuromuscular fatigue induced by a 90-minute soccer game modeling

This study aimed to quantify neuromuscular fatigue induced by a soccer game. Eight amateur soccer players (age 20.4 ± 1.3 years, mass 70.4 ± 6.9 kg, and height 174.9 ± 5.2 cm) reproduced a 90-minute soccer game modeling composed of two 45-minute periods separated by a 15-minute rest. Torque of quadriceps and hamstring muscle groups associated with electromyography, sprint speed, and vertical jump height was assessed before, at halftime, and immediately after the modeling. Most physical qualities decreased throughout the game with greater decays at match end than at halftime. Contrarily to quadriceps muscles, hamstring torque impairments were not accompanied by electromyographic activity reductions. Squat jump height was reduced at halftime and game end without any change for countermovement jumps. The sprint speed decrease was associated with stride frequency impairments without any change in amplitude and contact time. We concluded on torque production capacity and specific performance impairments during and after soccer games. Neuromuscular fatigue appeared primarily centrally mediated as attested by the reduced quadriceps muscle activity.     

Effects of strength training with elastic band programme on fitness components in young female handball players: a randomized controlled trial

This study examined the effect of a 10-week programme of strength training with elastic band (STEB) on fitness components in young female handball players. Twenty-six young female handball players (aged 15.8 ± 0.2 years) from the same club participated in this study. They were randomly assigned between experimental (EG; n = 13) and control (CG; n = 13) groups. The EG performed the STEB, replacing some handball-specific drills in the regular handball training. The CG followed the regular handball training (i.e., mainly technical-tactical drills, small sided and simulated games, and injury prevention drills). Two-way analyses of variance were used to assess: handgrip; back extensor strength; medicine ball throw; 30 m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests: squat jump (SJ), countermovement jump (CMJ), countermovement jump with arm swing (CMJA) and five-jump test (5JT); static (Stork test) and dynamic balance (Y Balance Test); and repeated sprint T-test (RSTT). Results revealed significant gains in handgrip - right (p < 0.001, d = 1.75: large), handgrip - left (p < 0.001, d = 2.52: large), back extensor (p < 0.001, d = 2.01: large), and medicine ball throw (p = 0.002, d = 0.95: large) with EG compared to the CG. The EG also demonstrated greater improvement in sprint performance over 20 m (Δ = 10.6%, p = 0.001, d = 1.07: large) and 30 m (Δ = 7.2%, p < 0.0001, d = 1.56: large) compared to the CG. The EG showed better Illinois-MT (Δ = 5.6%, p = 0.034, d = 0.62: medium) compared to the CG. Further, EG posted significant improvements in the SJ (Δ = 17.3%, p = 0.048, d = 0.58: medium), CMJ (Δ = 17.7%, p = 0.017 d = 0.71: medium), and CMJA (Δ = 16.3%, p = 0.019, d = 0.69: medium) compared to the CG. Similarly, the EG exhibited significant improvement in RSTT best time [p = 0.025, d = 0.66 (medium)], RSTT mean time [p = 0.019, d = 0.69 (medium)] and RSTT total time [p = 0.019, d = 0.69 (medium)] compared to the CG. In conclusion, the 10-week STEB improved the physical abilities in young female handball players.     

Strength and power characteristics in English elite rugby league players

The aim of this article is to present data on the strength and power characteristics of forwards and backs in a squad of elite English rugby league players and compare these findings to previously published literature from Australia. Participants were elite English rugby league players (n = 18; height 184.16 ± 5.76 cm; body mass 96.87 ± 10.92 kg, age 21.67 ± 4.10 years) who were all regular first team players for an English Superleague club. Testing included 5-, 10-, 20-m sprint times, agility, vertical jump, 40-kg squat jump, isometric squat, concentric and eccentric isokinetic knee flexion and extension. Independent t-tests were performed to compare results between forwards and backs, with paired samples t-tests used to compare bilateral differences from isokinetic assessments and agility tests. Forwards demonstrated significantly (p < 0.05) greater body mass (102.15 ± 7.5 kg), height (186.30 ± 5.47 cm), power during the 40-kg jump squat (2,106 ± 421 W), isometric force (3,122 ± 611 N) and peak torque during left concentric isokinetic knee extension (296.1 ± 54.2 N·m) compared to the backs (86.30 ± 8.97 kg; 179.87 ± 3.72 cm; 1,709 ± 286 W; 2,927 ± 607 N; 241.7 ± 35.2 N·m, respectively). However, no significant differences (p > 0.05) were noted between forwards and backs during right concentric isokinetic knee extension (274.8 ± 37.7 and 246.8 ± 25.8 N·m), concentric isokinetic knee flexion for both left (158.8 ± 28.6 and 141.0 ± 22. 7 N·m) and right legs (155.3 ± 22.9 and 128.0 ± 23.9 N·m), eccentric isokinetic knee flexion and extension, hamstring quadriceps ratios, or vertical jump (37.25 ± 4.35 and 40.33 ± 6.38 cm). In comparison, relative measures demonstrated that backs performed significantly better compared to the forwards during the 40-kg jump squat (20.71 ± 5.15 and 19.91 ± 3.91 W·kg?1) and the isometric squat (34.32 ± 7.9 and 30.65 ± 5.34 N·kg?1). Bilateral comparisons revealed no significant differences (p > 0.05) between left and right leg performances in the agility test (3.26 ± 0.18 and 3.24 ± 0.18 seconds), or between left (0.7 ± 0.10) and right (0.71 ± 0.17) leg eccentric hamstring concentric quadriceps ratios. The results demonstrate that absolute strength and power measures are generally higher in forwards compared to in backs; however, when body mass is taken into account and relative measures compared, the backs outperform the forwards.     

Physiological testing of basketball players: toward a standard evaluation of anaerobic fitness

The aim of this study was to examine whether the changes in the rules of the game instituted in 2000 have modified the physiological factors of success in basketball. The performances of 8 elite male players and 8 average-level players were compared in order to identify which components of fitness among agility, speed, anaerobic power, anaerobic capacity, and upper body strength were key determinants of performance in modern basketball. Each subject performed 7 tests, including vertical jump (VJ), 20-m sprint, agility T test, suicide sprint, 30-second Wingate anaerobic test (WAnT), isokinetic testing of the knee extensors, and 1 repetition maximum (1RM) bench press test. The statistical difference in the anaerobic performances was assessed by Student's t test. The main results showed that, compared to average-level players, elite-level players achieved significantly better performances in the agility T test (+6.2%), VJ test (+8.8%), peak torques developed by knee extensors (+20.2%), and 1RM bench press (+18.6%, p < 0.05). In contrast, no significant difference between groups was observed on 20-m sprint, suicide run, and parameters of the WAnT (p > 0.05). These results emphasized the importance of anaerobic power in modern basketball, whereas anaerobic capacity does not seem to be a key aspect to consider. In this context, coaches are advised to avoid using exercises lasting >/=30 seconds in their physical fitness programs, but instead to focus on short and intense tests such as VJ, agility T test, and sprints over very short distances (5 or 10 m).     

Correlates of tackling ability in high-performance rugby league players

This study investigated the tackling ability of high-performance rugby league players and determined the relationship between physiological and anthropometric qualities and tackling ability in these athletes. Twenty professional (National Rugby League) and 17 semiprofessional (Queensland Cup) rugby league players underwent a standardized 1-on-1 tackling drill in a 10-m grid. Video footage was taken from the rear, side, and front of the defending player. Tackling proficiency was assessed using standardized technical criteria. In addition, all players underwent measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), acceleration (10-m sprint), change of direction speed (505 test), and lower body muscular power (vertical jump). Professional players had significantly greater (p ≤ 0.05) tackling proficiency than semiprofessional players (87.5 ± 2.0 vs. 75.0 ± 2.3%). Professional players were significantly (p ≤ 0.05) older, more experienced, leaner, and had greater acceleration than semiprofessional players. The strongest individual correlates of tackling ability were age (r = 0.41, p ≤ 0.05), playing experience (r = 0.70, p ≤ 0.01), skinfold thickness (r = -0.59, p ≤ 0.01), acceleration (r = 0.41, p ≤ 0.05), and lower body muscular power (r = 0.38, p ≤ 0.05). When hierarchical multiple regression analysis was performed to determine which of the variables predicted tackling ability, playing experience and lower body muscular power were the only variables that contributed significantly (r2 = 0.60, p ≤ 0.01) to the predictive model. From a practical perspective, strength and conditioning coaches should emphasize the development of acceleration, lower body muscular power, and lean muscle mass to improve tackling ability in high-performance rugby league players.     

Validity of a squash-specific test of multiple-sprint ability

We examined the validity and reproducibility of a squash-specific multiple-sprint test. Eight male squash and 8 male soccer players performed Baker's 8 × 40-m sprints and a squash-specific-multiple-sprint test on separate days. The sum of individual sprint times in each test was recorded. Six squash and 6 soccer players repeated the tests 7 days later to assess reproducibility using intraclass correlation. In addition, 2 England Squash coaches independently ranked the squash players using knowledge of the player and recent performances in local leagues. Performance on the squash-specific (r = 0.97 and 0.90) and Baker's test (r = 0.95 and 0.83) was reproducible in squash and soccer players, respectively, and did not differ on Baker's test (mean ± SD 72.9 ± 3.9 and 72.9 ± 2.8 seconds for squash and soccer players, p = 0.969, effect size = 0.03). Squash players (232 ± 32 seconds) outperformed soccer players (264 ± 14 seconds) on the squash-specific test (p = 0.02, effect size = 1.39). Performance on Baker's and the squash-specific test were related in squash players (r = 0.98, p < 0.001) but not in soccer players (r = -0.08, p = 0.87). Squash-player rank correlated with performance on the squash-specific (ρ = 0.79, p = 0.02) but not the Baker's test (ρ = 0.55, p = 0.16). The squash-specific test discriminated between groups with similar non-sport-specific multiple-sprint ability and in squash players. In conjunction with the relationship between test performances, the results suggest that the squash-specific test is a valid and reproducible measure of multiple-sprint ability in squash players and could be used for assessing and tracking training-induced changes in multiple-sprint ability.     

Effects of in-season strength maintenance training frequency in professional soccer players

The aim of the present study was to examine the effect of in-season strength maintenance training frequency on strength, jump height, and 40-m sprint performance in professional soccer players. The players performed the same strength training program twice a week during a 10-week preparatory period. In-season, one group of players performed 1 strength maintenance training session per week (group 2 + 1; n = 7), whereas the other group performed 1 session every second week (group 2 + 0.5; n = 7). Only the strength training frequency during the in-season differed between the groups, whereas the exercise, sets and number of repetition maximum as well as soccer sessions were similar in the 2 groups. The preseason strength training resulted in an increased strength, sprint, and jump height (p < 0.05). During the first 12 weeks of the in-season, the initial gain in strength and 40-m sprint performance was maintained in group 2 + 1, whereas both strength and sprint performance were reduced in group 2 + 0.5 (p < 0.05). There was no statistical significant change in jump height in any of the 2 groups during the first 12 weeks of the in-season. In conclusion, performing 1 weekly strength maintenance session during the first 12 weeks of the in-season allowed professional soccer players to maintain the improved strength, sprint, and jump performance achieved during a preceding 10-week preparatory period. On the other hand, performing only 1 strength maintenance session every second week during the in-season resulted in reduced leg strength and 40-m sprint performance. The practical recommendation from the present study is that during a 12-week period, 1 strength maintenance session per week may be sufficient to maintain initial gain in strength and sprint performance achieved during a preceding preparatory period.     

Effects of official Taekwondo competitions on all-out performances of elite athletes

This study investigated physiological and performance aspects of 15 (4 women and 11 men) elite Taekwondo athletes (24.0 ± 5.7 years) during their National Championship. The load of the competition was evaluated by means of heart rate (HR) and blood lactate (La). Pre and postmatch countermovement jump (CMJ), and handgrip performances were compared (p < 0.05). The match imposed a high load (HR > 85% of individual HRmax = 92 ± 12%; La = 6.7 ± 2.5 mmol·L?1) on athletes. After the match, better (p < 0.0001) CMJ (men: 43.9 ± 5.2 cm; women: 30.8 ± 2.3 cm) and worst (p = 0.006) handgrip performances (men: 459 ± 87 N; women: 337 ± 70 N) were found with respect to prematch ones (CMJ: men = 40.8 ± 4.9 cm, women = 28.2 ± 2.5 cm; handgrip: men = 486 ± 88 N, women: 337 ± 70 N). Results indicate that the intermittent activity of the Taekwondo competition elicits a high neuromuscular activation of the lower limbs. Instead, the decreases in grip strength could be because of the repeated concussions on the upper limbs used to protect from the opponent's kicks and punches directed toward the scoring area of the torso. Practically, these results urge coaches to structure training sessions that enable athletes to maintain their upper limb strength during their match.     

The effects of enforced, rapid deceleration on performance in a multiple sprint test

The nature of multiple sprint sports such as soccer, hockey, and rugby is such that deceleration plays an important part in the movement patterns of players during a game and training. The purpose of this study was to investigate the effect of deceleration on fatigue during repeated sprint efforts. A group of 18 elite field hockey players (all men) performed a running repeated sprint ability test (6 x 40 m using maximal effort and departing every 30 seconds). In one condition, there was no deceleration zone, and in the second condition, the test had a deceleration component (rapid deceleration to a stop within 6 m of the end of each sprint). Sprint times under each condition were compared using a repeated-measures analysis of variance. No significant difference was seen between the 2 conditions for mean sprint times (p > 0.05) or for the mean fatigue index (p > 0.05). However, results showed a divergent trend, and further analysis extrapolating the data for an increased number of sprints showed that a significant difference (p < 0.05) would have been seen at the 11th sprint. Although this study found that the deceleration zone had little effect on the 6-sprint protocol, it was clear that the deceleration component would have shown an effect, giving rise to greater fatigue and slower sprint times, if the number of sprints had been increased. The implications are that deceleration training should be introduced into general fitness training programs for those competing in multiple sprint sports.