Performance changes during a college playing career in NCAA division III football athletes

The purpose of this study was to compare anthropometric and athletic performance variables during the playing career of NCAA Division III college football players. Two hundred and eighty-nine college football players were assessed for height, body mass, body composition, 1-repetition-maximum (1RM) bench press, 1RM squat, vertical jump height (VJ), vertical jump peak, and vertical jump mean (VJMP) power, 40-yd sprint speed (40S), agility, and line drill (LD) over an 8-year period. All testing occurred at the beginning of summer training camp in each of the seasons studied. Data from all years of testing were combined. Players in their fourth and fifth (red-shirt year) seasons of competition were significantly (p < 0.05) heavier than first-year players. Significant increases in strength were seen during the course of the athletes' collegiate career (31.0% improvement in the 1RM bench press and 36.0% increase in squat strength). The VJ was significantly greater during the fourth year of competition compared to in the previous 3 years of play. Vertical jump peak and VJMP were significantly elevated from years 1 and 2 and were significantly higher during year 4 than during any previous season of competition. No significant changes in 40S or LD time were seen during the athletes playing career. Fatigue rate for the LD (fastest time/slowest time of 3 LD) significantly improved from the first (83.4 ± 6.4%) to second season (85.1 ± 6.5%) of competition. Fatigue rates in the fourth (88.3 ± 4.8%) and fifth (91.2 ± 5.2%) seasons were significantly greater than in any previous season. Strength and power performance improvements appear to occur throughout the football playing career of NCAA Division III athletes. However, the ability to significantly improve speed and agility may be limited.     

The effects of ten weeks of resistance and combined plyometric/sprint training with the Meridian Elyte athletic shoe on muscular performance in women

The purpose of this investigation was to examine the combined effects of resistance and sprint/plyometric training with or without the Meridian Elyte athletic shoe on muscular performance in women. Fourteen resistance-trained women were randomly assigned to one of 2 training groups: (a) an athletic shoe (N = 6) (AS) group or (b) the Meridian Elyte (N = 8) (MS) group. Training was performed for 10 weeks and consisted of resistance training for 2 days per week and 2 days per week of sprint/plyometric training. Linear periodized resistance training consisted of 5 exercises per workout (4 lower body, 1 upper body) for 3 sets of 3-12 repetition maximum (RM). Sprint/plyometric training consisted of 5-7 exercises per workout (4-5 plyometric exercises, 40-yd and 60-yd sprints) for 3-6 sets with gradually increasing volume (8 weeks) followed by a 2-week taper phase. Assessments for 1RM squat and bench press, vertical jump, broad jump, sprint speed, and body composition were performed before and following the 10-week training period. Significant increases were observed in both AS and MS groups in 1RM squat (12.0 vs. 14.6 kg), bench press (6.8 vs. 7.4 kg), vertical jump height (3.3 vs. 2.3 cm), and broad jump (17.8 vs. 15.2 cm). Similar decreases in peak 20-, 40-, and 60-m sprint times were observed in both groups (20 m: 0.14 vs. 0.11 seconds; 40 m: 0.29 vs. 0.34 seconds; 60 m: 0.45 vs. 0.46 seconds in AS and MS groups, respectively). However, when sprint endurance (the difference between the fastest and slowest sprint trials) was analyzed, there was a significantly greater improvement at 60 m in the MS group. These results indicated that similar improvements in peak sprint speed and jumping ability were observed following 10 weeks of training with either shoe. However, high-intensity sprint endurance at 60 m increased to a greater extent during training with the Meridian Elyte athletic shoe.     

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).     

Relationship between functional movement screen and athletic performance

Parchmann, CJ and McBride, JM. Relationship between functional movement screen and athletic performance. J Strength Cond Res 25(12): 3378-3384, 2011-Tests such as the functional movement screen (FMS) and maximal strength (repetition maximum strength [1RM]) have been theorized to assist in predicting athletic performance capabilities. Some data exist concerning 1RM and athletic performance, but very limited data exist concerning the potential ability of FMS to assess athletic performance. The purpose of this investigation was to determine if FMS scores or 1RM is related to athletic performance, specifically in Division I golfers in terms of sprint times, vertical jump (VJ) height, agility T-test times, and club head velocity. Twenty-five National Collegiate Athletic Association Division I golfers (15 men, age = 20.0 ± 1.2 years, height = 176.8 ± 5.6 cm, body mass = 76.5 ± 13.4 kg, squat 1RM = 97.1 ± 21.0 kg) (10 women, age = 20.5 ± 0.8 years, height = 167.0 ± 5.6 cm, body mass = 70.7 ± 21.5 kg, squat 1RM = 50.3 ± 16.6) performed an FMS, 1RM testing, and field tests common in assessing athletic performance. Athletic performance tests included 10- and 20-m sprint time, VJ height, agility T-test time, and club head velocity. Strength testing included a 1RM back squat. Data for 1RM testing were normalized to body mass for comparisons. Correlations were determined between FMS, 1RMs, and athletic performance tests using Pearson product correlation coefficients (p ≤ 0.05). No significant correlations existed between FMS and 10-m sprint time (r = -0.136), 20-m sprint time (r = -0.107), VJ height (r = 0.249), agility T-test time (r = -0.146), and club head velocity (r = -0.064). The 1RM in the squat was significantly correlated to 10-m sprint time (r = -0.812), 20-m sprint time (r = -0.872), VJ height (r = 0.869), agility T-test time (r = -0.758), and club head velocity (r = 0.805). The lack of relationship suggests that FMS is not an adequate field test and does not relate to any aspect of athletic performance. Based on the data from this investigation, 1RM squat strength appears to be a good indicator of athletic performance.     

Effect of direct supervision of a strength coach on measures of muscular strength and power in young rugby league players

The purpose of the present study was to examine the influence of direct supervision on muscular strength, power, and running speed during 12 weeks of resistance training in young rugby league players. Two matched groups of young (16.7 +/- 1.1 years [mean +/- SD]), talented rugby league players completed the same periodized resistance-training program in either a supervised (SUP) (N = 21) or an unsupervised (UNSUP) (N = 21) environment. Measures of 3 repetition maximum (3RM) bench press, 3RM squat, maximal chin-ups, vertical jump, 10- and 20-m sprints, and body mass were completed pretest (week 0), midtest (week 6), and posttest (week 12) training program. Results show that 12 weeks of periodized resistance training resulted in an increased body mass, 3RM bench press, 3RM squat, maximum number of chin-ups, vertical jump height, and 10- and 20-m sprint performance in both groups (p < 0.05). The SUP group completed significantly more training sessions, which were significantly correlated to strength increases for 3RM bench press and squat (p < 0.05). Furthermore, the SUP group significantly increased 3RM squat strength (at 6 and 12 weeks) and 3RM bench press strength (12 weeks) when compared to the UNSUP group (p < 0.05). Finally, the percent increase in the 3RM bench press, 3RM squat, and chin-up(max) was also significantly greater in the SUP group than in the UNSUP group (p < 0.05). These findings show that the direct supervision of resistance training in young athletes results in greater training adherence and increased strength gains than does unsupervised training.     

Short-term effects on lower-body functional power development: weightlifting vs. vertical jump training programs

Among sport conditioning coaches, there is considerable discussion regarding the efficiency of training methods that improve lower-body power. Heavy resistance training combined with vertical jump (VJ) training is a well-established training method; however, there is a lack of information about its combination with Olympic weightlifting (WL) exercises. Therefore, the purpose of this study was to compare the short-term effects of heavy resistance training combined with either the VJ or WL program. Thirty-two young men were assigned to 3 groups: WL = 12, VJ = 12, and control = 8. These 32 men participated in an 8-week training study. The WL training program consisted of 3 x 6RM high pull, 4 x 4RM power clean, and 4 x 4RM clean and jerk. The VJ training program consisted of 6 x 4 double-leg hurdle hops, 4 x 4 alternated single-leg hurdle hops, 4 x 4 single-leg hurdle hops, and 4 x 4 40-cm drop jumps. Additionally, both groups performed 4 x 6RM half-squat exercises. Training volume was increased after 4 weeks. Pretesting and posttesting consisted of squat jump (SJ) and countermovement jump (CMJ) tests, 10- and 30-m sprint speeds, an agility test, a half-squat 1RM, and a clean-and-jerk 1RM (only for WL). The WL program significantly increased the 10-m sprint speed (p < 0.05). Both groups, WL and VJ, increased CMJ (p < 0.05), but groups using the WL program increased more than those using the VJ program. On the other hand, the group using the VJ program increased its 1RM half-squat strength more than the WL group (47.8 and 43.7%, respectively). Only the WL group improved in the SJ (9.5%). There were no significant changes in the control group. In conclusion, Olympic WL exercises seemed to produce broader performance improvements than VJ exercises in physically active subjects.     

The relationship between core stability and performance in division I football players

The purpose of this study was to identify relationships between core stability and various strength and power variables in strength and power athletes. National Collegiate Athletic Association Division I football players (height 184.0 +/- 7.1 cm, weight 100.5 +/- 22.4 kg) completed strength and performance testing before off-season conditioning. Subjects were tested on three strength variables (one-repetition maximum [1RM] bench press, 1RM squat, and 1RM power clean), four performance variables (countermovement vertical jump [CMJ], 20- and 40-yd sprints, and a 10-yd shuttle run), and core stability (back extension, trunk flexion, and left and right bridge). Significant correlations were identified between total core strength and 20-yd sprint (r = -0.594), 40-yd sprint (r = -0.604), shuttle run (r = -0.551), CMJ (r = 0.591), power clean/body weight (BW) (r = 0.622), 1RM squat (r = -0.470), bench press/BW (r = 0.369), and combined 1RM/BW (r = 0.447); trunk flexion and 20-yd sprint (r = -0.485), 40-yd sprint (r = -0.479), shuttle run (r = -0.443), CMJ (r = 0.436), power clean/BW (r = 0.396), and 1RM squat (r = -0.416); back extension and CMJ (r = 0.536), and power clean/BW (r = 0.449); right bridge and 20-yd sprint r = -0.410) and 40-yd sprint (r = -0.435), CMJ (r = 0.403), power clean/BW (r = 0.519) and bench press/BW (r = 0.372) and combined 1RM/BW (r = 0.406); and left bridge and 20-yd sprint (r = -0.376) and 40-yd sprint (r = -0.397), shuttle run (r = -0.374), and power clean/BW (r = 0.460). The results of this study suggest that core stability is moderately related to strength and performance. Thus, increases in core strength are not going to contribute significantly to strength and power and should not be the focus of strength and conditioning.     

Comparison of loaded and unloaded jump squat training on strength/power performance in college football players

The purpose of this study was to explore the effects of 5 weeks of eccentrically loaded and unloaded jump squat training in experienced resistance-trained athletes during the strength/ power phase of a 15-week periodized off-season resistance training program. Forty-seven male college football players were randomly assigned to 1 of 3 groups. One group performed the jump squat exercise using both concentric and eccentric phases of contraction (CE; n = 15). A second group performed the jump squat exercise using the concentric phase only (n = 16), and a third group did not perform the jump squat exercise and served as control (CT; n = 16). No significant differences between the groups were seen in power, vertical jump height, 40-yd sprint speed and agility performance. In addition, no differences between the groups were seen in integrated electromyography activity during the jump squat exercise. Significant differences between the CE and CT groups were seen in Delta 1RM squat (65.8 and 27.5 kg, respectively) and Delta 1RM power clean (25.9 and 3.8 kg, respectively). No other between-group differences were observed. Results of this study provide evidence of the benefits of the jump squat exercise during a short-duration (5-week) training program for eliciting strength and power gains. In addition, the eccentric phase of this ballistic movement appears to have important implications for eliciting these strength gains in college football players during an off-season training program. Thus, coaches incorporating jump squats (using both concentric and eccentric phases of contraction) in the off-season training programs of their athletes can see significant performance improvements during a relatively short duration of training.     

Anthropometrical, physiological, and tracked power profiles of elite taekwondo athletes 9 weeks before the Olympic competition phase

Physiological, anthropometric, and power profiling data were retrospectively analyzed from 4 elite taekwondo athletes from the Australian National Olympic team 9 weeks from Olympic departure. Power profiling data were collected weekly throughout the 9-week period. Anthropometric skinfolds generated a lean mass index (LMI). Physiological tests included a squat jump and bench throw power profile, bleep test, 20-m sprint test, running VO2max test, and bench press and squat 3 repetition maximum (3RM) strength tests. After this, the athletes power, velocity, and acceleration profile during unweighted squat jumps and single-leg jumps were tracked using a linear position transducer. Increases in power, velocity, and acceleration between weeks and bilateral comparisons were analyzed. Athletes had an LMI of 37.1 ± 0.4 and were 173.9 ± 0.2 m and 67 ± 1.1 kg. Relatively weaker upper body (56 ± 11.97 kg 3RM bench press) compared to lower body strength (88 ± 2.89 kg 3RM squat) was shown alongside a VO2max of 53.29 ml(-1)·min(-1)·kg, and a 20-m sprint time of 3.37 seconds. Increases in all power variables for single-leg squat and squat jumps were found from the first session to the last. Absolute peak power in single-leg squat jumps increased by 13.4-16% for the left and right legs with a 12.9% increase in squat jump peak power. Allometrically scaled peak power showed greater increases for single-leg (right leg: 18.55%; left: 23.49%) and squat jump (14.49%). The athlete's weight did not change significantly throughout the 9-week mesocycle. Progressions in power increases throughout the weeks were undulating and can be related to the intensity of the prior week's training and athlete injury. This analysis has shown that a 9-week mesocycle before Olympic departure that focuses on core lifts has the ability to improve power considerably.     

Comparison of muscle force production using the Smith machine and free weights for bench press and squat exercises

The Smith machine (SM) (vertical motion of bar on fixed path; fixed-form exercise) and free weights (FWs) (free-form path) are commonly used strength training modes. Exercisers may need to alternate between types of equipment, depending on testing, training, rehabilitation, and/or the exercisers' goals. The purposes of this study were to compare muscle force production for SM and FWs using a 1 repetition maximum (1RM) for the parallel back squat and supine bench press exercises and to predict the 1RM for one mode from 1RM on the other mode. Men (n = 16) and women (n = 16) alternately completed 1RM testing for squat and bench press using SM and FWs. Analyses of variance (type of equipment x sex) and linear regression models were calculated. A significant difference was found between bench press and squat 1RMs for each mode of equipment for all participants. The squat 1RM was greater for the SM than the FWs; conversely, the bench 1RM was greater for FWs than the SM. When sex was considered, bench 1RM for FWs was greater than SM for men and women. The squat 1RM was greater for SM than FWs for women only. The 1RM on one mode of equipment was the best predictor of 1RM for the other mode. For both sexes, the equation SM bench 1RM (in kilograms) = -6.76 + 0.95 (FW bench 1RM) can be used. For women only, SM squat 1RM (in kilograms) = 28.3 + 0.73 (FW squat 1RM). These findings provide equations for converting between SM and FW equipment for training.     

The effects of ten weeks of lower-body unstable surface training on markers of athletic performance

Initially reserved for rehabilitation programs, unstable surface training (UST) has recently grown in popularity in strength and conditioning and general exercise scenarios. Nonetheless, no studies to date have examined the effects of UST on performance in healthy, trained individuals. The purpose of this study was to determine the effects of 10 weeks of lower-body UST on performance in elite athletes. Nineteen healthy, trained members (ages 18-23 years) of a National Collegiate Athletic Association Division I collegiate men's soccer team participated. The experimental (US) group (n = 10) supplemented their normal conditioning program with lower-body exercises on inflatable rubber discs; the control (ST) group (n = 9) performed the same exercises on stable surfaces. Bounce drop jump (BDJ) and countermovement jump (CMJ) heights, 40- and 10-yard sprint times, and T-test (agility) times were assessed before and after the intervention. The ST group improved significantly on predicted power output on both the BDJ (3.2%) and CMJ (2.4%); no significant changes were noted in the US group. Both groups improved significantly on the 40- (US = -1.8%, ST = -3.9%) and 10-yard sprint times (US = -4.0%, ST = -7.6%). The ST group improved significantly more than the US group in 40-yard sprint time; a trend toward greater improvement in the ST group was apparent on the 10-yard sprint time. Both groups improved significantly (US = 2.9%, ST = -4.4%) on T-test performance; no statistically significant changes were apparent between the groups. These results indicate that UST using inflatable rubber discs attenuates performance improvements in healthy, trained athletes. Such implements have proved valuable in rehabilitation, but caution should be exercised when applying UST to athletic performance and general exercise scenarios.     

Validity of the Myotest® in measuring force and power production in the squat and bench press

The purpose of this study was to verify the concurrent validity of a bar-mounted Myotest? instrument in measuring the force and power production in the squat and bench press exercises when compared to the gold standard of a computerized linear transducer and force platform system. Fifty-four men (bench press: 39-171 kg; squat: 75-221 kg) and 43 women (bench press: 18-80 kg; squat: 30-115 kg) (age range 18-30 years) performed a 1 repetition maximum (1RM) strength test in bench press and squat exercises. Power testing consisted of the jump squat and the bench throw at 30% of each subject's 1RM. During each measurement, both the Myotest? instrument and the Celesco linear transducer of the directly interfaced BMS system (Ballistic Measurement System [BMS] Innervations Inc, Fitness Technology force plate, Skye, South Australia, Australia) were mounted to the weight bar. A strong, positive correlation (r) between the Myotest and BMS systems and a high correlation of determination (R2) was demonstrated for bench throw force (r = 0.95, p < 0.05) (R2 = 0.92); bench throw power (r = 0.96, p < 0.05) (R2 = 0.93); squat jump force (r = 0.98, p < 0.05) (R2 = 0.97); and squat jump power (r = 0.91, p < 0.05) (R2 = 0.82). In conclusion, when fixed on the bar in the vertical axis, the Myotest is a valid field instrument for measuring force and power in commonly used exercise movements.     

Influence of contraction velocity in untrained individuals over the initial early phase of resistance training

The purpose of this study was to determine the early phase adaptations in short-term traditional (TRT) versus superslow (SST) resistance training. Sixteen apparently healthy subjects participated in this study. Subjects were pretested and posttested for their 1 repetition maximums (1RM) in the squat and bench press, peak power in a countermovement jump (CMJ) and squat jump (SJ), and body composition using dual energy x-ray absorptiometry. Subjects participated in an 8-week resistance training program in either SST (n = 9, 3 men, 6 women), using 50% of 1RM, or TRT (n = 7, 3 men, 4 women), using 80% of 1RM. Both groups trained 3 days per week. The TRT and SST groups improved in strength by 6.8 and 3.6% in the squat exercise and by 8.6 and 9.1% in the bench press, respectively. Peak power for the CMJ increased significantly in the TRT group, from 23.0 +/- 5.5 W/kg to 25.0 +/- 6.3 W/kg; no such increase was seen with respect to the SST group. Both groups' 1RM increased significantly for both the bench press and the squat. No changes in body composition were seen for either group. The results of this study suggest that TRT is more effective for improving peak power than SST.     

Acute effects of heavy preloading on vertical and horizontal jump performance

The purpose of this study was to investigate the acute effects of a heavy dynamic preload, consisting of 1 set of 5 repetition maximum (5RM) back squats, on countermovement vertical jump (VJ) and horizontal jump (HJ) performance. The study also investigated the ability of subjects to learn to apply the effects of the preload over subsequent training sessions. Nineteen (N = 19) resistance-trained men (age = 25.0 +/- 4.8 years; weight = 79.3 +/- 6.6 kg) participated in the study. Each subject took part in 4 practice and 4 testing sessions. The 4 practice sessions were included to allow for any learning effects of VJ and HJ to stabilize and to establish a true 5RM back squat. The 4 testing sessions were included to see if subjects were able to capitalize on the repeat exposure to the protocol. One practice session consisted of a 10-minute warm-up (5 minutes of cycling and 5 minutes of stretching), 2 sets of VJ and HJ (each set of VJ and HJ consisted of 4 jump repetitions) with a 5-minute rest between sets, progressive 5RM back squat evaluation, and 2 final sets of VJ and HJ. Both VJ and HJ increased approximately 2% over the 4 practice sessions, and 5RM back squat strength improved from 164.2 +/- 25.1 kg to 196.9 +/- 23.0 kg (p < or = 0.05). The 4 testing sessions each consisted of the standardized warm-up, 1 set of 4 VJs and HJs, a 5-minute rest, 5RM back squat, a 5-minute rest, and the final set of VJs and HJs. Pre- and post-5RM VJ and HJ order was randomly assigned. The results indicated no significant differences occurred between the mean or maximal values for either VJ or HJ as a consequence of the dynamic preload exercise. In addition, the results reflected an inability of subjects to benefit from the repeated exposure to the heavy dynamic preload exercise protocol.     

A physical profile of elite female ice hockey players from the USA

Despite impressive numbers of hockey participants, there is little research examining elite female ice hockey players. Therefore, the purpose of this study was to describe the physical characteristics of elite female ice hockey players who were trying out for the 2010 US Women's Ice Hockey team. Twenty-three women participated in the study and were evaluated for body mass (kilograms), height (centimeters), age (years) vertical jump (centimeters), standing long jump (centimeters), 1RM front squat (kilograms), front squat relative to body mass (percent), 1RM bench press (kilograms), bench press relative to body mass (percent), pull-ups, and body composition (percent body fat). The athletes in this sample were 24.7 years of age (SD = 3.1) and 169.7 cm tall (SD = 6.9); on average, they weighed 70.4 kg (SD = 7.1) and reported 15.8% body fat (SD = 1.9). Mean vertical jump height was 50.3 cm (SD = 5.7) and standing long jump was 214.8 cm (SD = 10.9). Mean 1RM for the upper body strength (bench press) was 65.3 kg (SD = 12.2) (95.1 ± 15.5% of body mass), and 1RM for lower body (front squat) was 88.6 kg (SD = 11.2) (127.7 ± 16.3% of body mass). This study is the first to report the physical characteristics of elite female ice hockey players from the USA. Data should assist strength and conditioning coaches in identifying talent, testing for strengths and weaknesses, comparing future teams to these indicators, and designing programs that will enhance the performance capabilities of female ice hockey athletes.     

Effect of core strength on the measure of power in the extremities

The purpose of this study was to (a) develop a functional field test to assess the role of the core musculature and its impact on sport performance in an athletic population and (b) develop a functional field test to determine how well the core can transfer forces from the lower to the upper extremities. Twenty-five DI collegiate football players performed medicine ball throws (forward, reverse, right, and left) in static and dynamic positions. The results of the medicine ball throws were compared with several athletic performance measurements: 1 repetition maximum (1RM) squat, squat kg/bw, 1RM bench press, bench kg/bw, countermovement vertical jump (CMJ), 40-yd dash (40 yd), and proagility (PrA). Push press power (PWR) was used to measure the transfer of forces through the body. Several correlations were found in both the static and dynamic medicine ball throws when compared with the performance measures. Static reverse correlated with CMJ (r = 0.44), 40 yd (r = 0.5), and PrA (r = 0.46). Static left correlated with bench kg/bw (0.42), CMJ (0.44), 40 yd (0.62), and PrA (0.59). Static right also correlated with bench kg/bw (0.41), 40 yd (0.44), and PrA (0.65). Dynamic forward (DyFw) correlated with the 1RM squat (r = 0.45) and 1RM bench (0.41). Dynamic left and Dynamic right correlated with CMJ, r = 0.48 and r = 0.40, respectively. Push press power correlated with bench kg/bw (0.50), CMJ (0.48), and PrA (0.48). A stepwise regression for PWR prediction identified 1RM squat as the best predictor. The results indicate that core strength does have a significant effect on an athlete's ability to create and transfer forces to the extremities. Currently, plank exercises are considered an adequate method of training the core for athletes to improve core strength and stability. This is a problem because it puts the athletes in a nonfunctional static position that is very rarely replicated in the demands of sport-related activities. The core is the center of most kinetic chains in the body and should be trained accordingly.     

Short-term effects of strength and plyometric training on sprint and jump performance in professional soccer players

The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power-related measurements in professional soccer players. Subjects in the intervention team were randomly divided into 2 groups. Group ST (n = 6) performed heavy strength training twice a week for 7 weeks in addition to 6 to 8 soccer sessions a week. Group ST+P (n = 8) performed a plyometric training program in addition to the same training as the ST group. The control group (n = 7) performed 6 to 8 soccer sessions a week. Pretests and posttests were 1 repetition maximum (1RM) half squat, countermovement jump (CMJ), squat jump (SJ), 4-bounce test (4BT), peak power in half squat with 20 kg, 35 kg, and 50 kg (PP20, PP35, and PP50, respectively), sprint acceleration, peak sprint velocity, and total time on 40-m sprint. There were no significant differences between the ST+P group and ST group. Thus, the groups were pooled into 1 intervention group. The intervention group significantly improved in all measurements except CMJ, while the control group showed significant improvements only in PP20. There was a significant difference in relative improvement between the intervention group and control group in 1RM half squat, 4BT, and SJ. However, a significant difference between groups was not observed in PP20, PP35, sprint acceleration, peak sprinting velocity, and total time on 40-m sprint. The results suggest that there are no significant performance-enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6 to 8 soccer sessions a week compared to strength training alone. However, heavy strength training leads to significant gains in strength and power-related measurements in professional soccer players.     

Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting

The purpose of this study was to quantify the magnitude of the relationship between vertical jumping and maximal sprinting at different distances with performance in the traditional and ballistic concentric squat exercise in well-trained sprinters. Twenty-one men performed 2 types of barbell squats (ballistic and traditional) across different loads with the aim of determining the maximal peak and average power outputs and 1 repetition maximum (1RM) values. Moreover, vertical jumping (countermovement jump test [CMJ]) and maximal sprints over 10, 20, 30, 40, 60, and 80 m were also assessed. In respect to 1RM in traditional squat, (a) no significant correlation was found with CMJ performance; (b) positive strong relationships (p < 0.01) were obtained with all the power measures obtained during both ballistic and traditional squat exercises (r = 0.53-0.90); (c) negative significant correlations (r = -0.49 to -0.59, p < 0.05) were found with sprint times in all the sprint distances measured when squat strength was expressed as a relative value; however, in the absolute mode, no significant relationships were observed with 10- and 20-m sprint times. No significant relationship was found between 10-m sprint time and relative or absolute power outputs using either ballistic or traditional squat exercises. Sprint time at 20 m was only related to ballistic and traditional squat performance when power values were expressed in relative terms. Moderate significant correlations (r = -0.39 to -0.56, p < 0.05) were observed between sprint times at 30 and 40 m and the absolute/relative power measures attained in both ballistic and traditional squat exercises. Sprint times at 60 and 80 m were mainly related to ballistic squat power outputs. Although correlations can only give insights into associations and not into cause and effect, from this investigation, it can be seen that traditional squat strength has little in common with CMJ performance and that relative 1RM and power outputs for both squat exercises are statistically correlated to most sprint distances underlying the importance of strength and power to sprinting.     

Effects of 8-week in-season upper and lower limb heavy resistance training on the peak power, throwing velocity, and sprint performance of elite male handball players

The aims of this study were to test the potential of in-season heavy upper and lower limb strength training to enhance peak power output (Wpeak), vertical jump, and handball related field performance in elite male handball players who were apparently already well trained, and to assess any adverse effects on sprint velocity. Twenty-four competitors were divided randomly between a heavy resistance (HR) group (age 20 ± 0.7 years) and a control group (C; age 20 ± 0.1 years). Resistance training sessions were performed twice a week for 8 weeks. Performance was assessed before and after conditioning. Peak power (W(peak)) was determined by cycle ergometer; vertical squat jump (SJ) and countermovement jump (CMJ); video analyses assessed velocities during the first step (V(1S)), the first 5 m (V(5m)), and between 25 and 30 m (V(peak)) of a 30-m sprint. Upper limb bench press and pull-over exercises and lower limb back half squats were performed to 1-repetition maximum (1RM). Upper limb, leg, and thigh muscle volumes and mean thigh cross-sectional area (CSA) were assessed by anthropometry. W(peak) (W) for both limbs (p < 0.001), vertical jump height (p < 0.01 for both SJ and CMJ), 1RM (p < 0.001 for both upper and lower limbs) and sprint velocities (p < 0.01 for V(1S) and V(5m); p < 0.001 for V(peak)) improved in the HR group. Upper body, leg, and thigh muscle volumes and thigh CSA also increased significantly after strength training. We conclude that in-season biweekly heavy back half-squat, pull-over, and bench-press exercises can be commended to elite male handball players as improving many measures of handball-related performance without adverse effects upon speed of movement.     

Maximal power at different percentages of one repetition maximum: influence of resistance and gender

National Collegiate Athletic Association Division I athletes were tested to determine the load at which maximal mechanical output is achieved. Athletes performed power testing at 30, 40, 50, 60, and 70% of individual 1 repetition maximum (1RM) in the squat jump, bench press, and hang pull exercises. Additionally, hang pull power testing was performed using free-form (i.e., barbell) and fixed-form (i.e., Smith machine) techniques. There were differences between genders in optimal power output during the squat jump (30-40% of 1RM for men; 30-50% of 1RM for women) and bench throw (30% of 1RM for men; 30-50% of 1RM for women) exercises. There were no gender or form interactions during the hang pull exercise; maximal power output during the hang pull occurred at 30-60% of 1RM. In conclusion, these results indicate that (a) gender differences exist in the load at which maximal power output occurs during the squat jump and bench throw; and (b) although no gender or form interactions occurred during the hang pull exercise, greater power could be generated during fixed-form exercise. In general, 30% of 1RM will elicit peak power outputs for both genders and all exercises used in this study, allowing this standard percentage to be used as a starting point in order to train maximal mechanical power output capabilities in these lifts in strength trained athletes.