Effect of torso rotational strength on angular hip, angular shoulder, and linear bat velocities of high school baseball players

This investigation examined the effect of torso rotational strength on angular hip (AHV), angular shoulder (ASV), linear bat-end (BEV), and hand velocities (HV) and 3 repetition maximum (RM) torso rotational and sequential hip-torso-arm rotational strength (medicine ball hitter's throw) in high school baseball players (age 15.4 +/- 1.2 y). Participants were randomly assigned to 1 of 2 training groups. Group 1 (n = 24) and group 2 (n = 25) both performed a stepwise periodized resistance exercise program and took 100 swings a day, 3 days a week, for 12 weeks with their normal game bat. Group 2 performed additional rotational and full-body medicine ball exercises 3 days a week for 12 weeks. A 3RM parallel squat and bench press were measured at 0 and after 4, 8, and 12 weeks. Participants were pre- and posttested for 3RM dominant and nondominant torso rotational strength and medicine ball hitter's throw. Angular hip velocities, ASV, BEV, and HV were recorded pre- and posttraining by a motion capture system that identified and digitally processed reflective markers attached to each participant's bat and body. Groups 1 and 2 increased (p < or = 0.05) BEV (3.6 and 6.4%), HV (2.6 and 3.6%), 3RM dominant (10.5 and 17.1%) and nondominant (10.2 and 18.3%) torso rotational strength, and medicine ball hitter's throw (3.0 and 10.6%) after 12 weeks. Group 2 increased AHV (6.8%) and ASV (8.8%). Group 2 showed greater improvements in BEV, AHV, ASV, 3RM dominant and nondominant torso rotational strength, and medicine ball hitter's throw than group 1. Groups 1 and 2 increased predicted 1RM parallel squat (29.7 and 26.7%) and bench press (17.2 and 16.7%) strength after 12 weeks. These data indicate that performing additional rotational medicine ball exercises 2 days a week for 12 weeks statistically improves baseball performance variables.     

The relation between anthropometric and physiological variables and bat velocity of high-school baseball players before and after 12 weeks of training

The purpose of this article was to investigate the relation between anthropometric and physiological variables to linear bat swing velocity (BV) of 2 groups of high-school baseball players before and after completing a 12-week periodized resistance exercise program. Participants were randomly assigned to 1 of 2 training groups using a stratified sampling technique. Group 1 (n = 24) and group 2 (n = 25) both performed a stepwise periodized resistance exercise program and took 100 swings a day, 3 d·wk-1, for 12 weeks with their normal game bat. Group 2 performed additional rotational and full-body medicine ball exercises 3 d·wk-1 for 12 weeks. Fourteen variables were measured or calculated before and after 12 weeks of training. Anthropometric and physiological variables tested were height, body mass, percent body fat, lean body mass (LBM), dominant torso rotational strength (DTRS) and nondominant torso rotational strength (NDTRS), sequential hip-torso-arm rotational strength measured by a medicine ball hitter's throw (MBHT), estimated 1 repetition maximum parallel squat (PS) and bench press (BP), vertical jump (VJ), estimated peak power, angular hip velocity (AHV), and angular shoulder velocity (ASV). The baseball-specific skill of linear BV was also measured. Statistical analysis indicated a significant moderately high positive relationship (p ≤ 0.05) between prelinear BV and pre-NDTRS for group 1, pre-LBM, DTRS, NDTRS, peak power, and ASV for group 2; moderate positive relationship between prelinear BV and preheight, LBM, DTRS, peak power, BP, PS, and ASV for group 1, preheight, body mass, MBHT, BP, and PS for group 2. Significantly high positive relationships were indicated between postlinear BV and post-NDTRS for group 1, post-DTRS and NDTRS for group 2; moderately high positive relationships between postlinear BV and post-LBM, DTRS, peak power, BP, and PS for group 1, postheight, LBM, VJ, peak power for group 2; moderate positive relationships between postlinear BV and postheight, body mass, MBHT, and VJ for group 1, postbody mass, MBHT, BP, PS, and ASV for group 2. Significantly low positive relationships were indicated between prelinear BV and prebody mass, MBHT, and VJ for group 1, pre-VJ and AHV for group 2; postlinear BV and post-AHV for group 2. These data show that significant relationships do exist between height, body mass, LBM, rotational power, rotational strength, lower body power, upper and lower body strength, AHV, and ASV to linear BV of high-school baseball players. Strength coaches may want to consider using this information when designing a resistance training program for high-school baseball players. Those recruiting or scouting baseball players may want to use this information to further develop ways of identifying talented players. However, one should be cautious when interpreting this information when designing strength training programs for high-school baseball players to increase linear BV.     

Effect of wrist and forearm training on linear bat-end, center of percussion, and hand velocities and on time to ball contact of high school baseball players

This study examined the effects of 12 weeks of wrist and forearm training on linear bat-end velocity (BV), center of percussion velocity (CV), hand velocity (HV), and time to ball contact of high school baseball players. Forty-three baseball players were randomly assigned by a stratified sampling technique to 1 of 2 training groups. Group 1 (n = 23) and group 2 (n = 20) performed the same full-body resistance exercises while training 3 days a week for 12 weeks according to a stepwise periodized model. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks. Wrist and forearm strength were measured pre- and posttraining. Linear BV, CV, HV, and time to ball contact were recorded pre- and posttraining by a motion-capture system. A 3 repetition maximum (RM) parallel squat and bench press were measured at baseline and after 4, 8, and 12 weeks of training. Both groups showed statistically significant increases (p < or = 0.01) in linear BV, CV, and HV (m.s(-1) +/- SD) after 12 weeks of training; however, there were no differences between the 2 groups. Both groups statistically increased wrist and forearm strength (p < or = 0.05). Group 2 had statistically greater increases (p < or = 0.05) in 10 of 12 wrist and forearm strength measures than did group 1. Both groups made statistically significant increases in predicted 1RM parallel squat and bench press after 4, 8, and 12 weeks of training; however, there were no differences between groups. These data indicate that a 12-week stepwise periodized training program can significantly increase wrist and forearm strength, linear BV, CV, and HV among high school baseball players. However, increased wrist and forearm strength did not contribute to further increases in linear BV, CV, or HV.     

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.     

Effect of 12 weeks of wrist and forearm training on high school baseball players

This study examined the effect of 12 weeks of wrist and forearm training on male high school baseball players (mean age = 15.3 +/- 1.1 years). Participants (N = 43) were tested for 10 repetition maximum (RM) wrist barbell flexion, wrist barbell extension, dominant (D) and nondominant (ND) hand-forearm supination, D and ND forearm pronation, D and ND wrist radial deviation, D and ND wrist ulnar deviation, D and ND grip strength, and a 3RM parallel squat (PS) and bench press (BP). Group 1 (n = 23) and group 2 (n = 20), randomly assigned by a stratified sampling technique, performed the same resistance exercises while training 3 days a week for 12 weeks according to a stepwise periodized model. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks to determine if additional wrist and forearm training provided further wrist and forearm strength improvements. All wrist and forearm strength variables were measured before and after 12 weeks of training. The 3RM PS and BP were measured at 0 and after 4, 8, and 12 weeks of training. Both groups significantly increased wrist and forearm strength (kg +/- SD) except 10RM D and ND forearm supination for group 1 (p < 0.05). Group 2 showed statistically greater improvements (p < 0.05) in all wrist and forearm strength variables than did group 1 except for D and ND grip strength. Predicted 1RM (kg +/- SD) PS and BP increased significantly (p < 0.05) after weeks 4, 8, and 12 for both groups. These data indicate that a 12-week stepwise periodized training program can significantly increase wrist, forearm, PS, and BP strength for both groups. Additionally, group 2 had further wrist and forearm strength gains.     

Effects of 12-week medicine ball training on muscle strength and power in young female handball players

The purpose of this study was to examine the effects of medicine ball training on the strength and power in young female handball athletes. Twenty-one young female handball players (age, 16.9 ± 1.2 years) were randomly assigned to experimental and control groups. Experimental group (n = 11) participated in a 12-week medicine ball training program incorporated into the regular training session, whereas controls (n = 10) participated only in the regular training. Performance in the medicine ball throws in standing and sitting positions, 1 repetition maximum (1RM) bench and shoulder press, and power test at 2 different loads (30 and 50% of 1RM) on bench and shoulder press were assessed at pre- and posttraining testing. The athletes participating in the medicine ball training program made significantly greater gains in all medicine ball throw tests compared with the controls (p < 0.01). Also, the experimental group made significantly greater gains in bench and shoulder press power than control group (p < 0.05). Both training groups (E) and (C) significantly (p < 0.05) increased 1RM bench and shoulder strength, with no differences observed between the groups. Additionally, medicine ball throw tests showed stronger correlation with power tests, than with 1RM tests. These data suggest that 12-week medicine ball training, when incorporated into a regular training session, can provide greater sport-specific training improvements in the upper body for young female handball players.     

Relationship between upper-body strength and bat swing speed in high-school baseball players

This study aimed to clarify the relationship between upper-body strength and bat swing speed in high-school baseball players and to examine the physical characteristics of home run hitters (sluggers). The subjects were 30 male high-school baseball players with national tournament experience at the Koshien Stadium. Bat swing speed exerted by full effort was measured with a microwave-type speed-measuring instrument. One-repetition maximum (1RM) of a bench press (BP), BP power (bench power) using a light load (30 kg), and isokinetic chest press (0.4, 0.8, 1.2 m·s(-1)) were measured as upper-body strength. The relationships between bat swing speed and upper-body strength values were examined. Additionally, the t-test was used to reveal the mean differences between 14 home run hitters (group A) and 16 mediocre hitters (group B) for each measurement value. The bat swing speed showed significant and middle correlations with the 1RM BP (r = 0.59), bench power (0.41), and isokinetic chest press (0.48-0.55). Group A had significantly higher values in bench power and isokinetic chest press (high-speed) per kilogram of body weight than did group B. The swing speed showed significant correlations (r = 0.62) with the 1RM BP in group B but not in group A. In conclusion, to improve the hitting power of high-school baseball players, it may also be important to develop bench power with light loads in addition to 1RM BP.     

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.     

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.     

Strength changes during an in-season resistance-training program for football

The purpose of this study was to examine the effects of both intensity and volume of training during a 2 d.wk(-1) in-season resistance-training program (RTP) for American football players. Fifty-three National Collegiate Athletic Association Division III football players were tested in the 1 repetition maximum (1RM) bench press and 1RM squat on the first day of summer training camp (PRE) and during the final week of the regular season (POST). Subjects were required to perform 3 sets of 6-8 repetitions per exercise. Significant strength improvements in squat were observed from PRE (155.0 +/- 31.8 kg) to POST (163.3 +/- 30.0 kg), whereas no PRE to POST changes in bench press were seen (124.7 +/- 21.0 kg vs.123.9 +/- 18.6 kg, respectively). Training volume and training compliance were not related to strength improvement. Further analysis showed that athletes training at >or=80% of their PRE 1RM had significantly greater strength improvements than athletes training at <80% of their PRE 1RM, for both bench press and squat. Strength improvements can be seen in American football players, during an in-season RTP, as long as exercise intensity is >or=80% of the 1RM.     

Effect of various warm-up devices on bat velocity of intercollegiate baseball players

A variety of warm-up devices are available to baseball players to use before their game at-bat. Past baseball research evaluating warm-up devices indicates that implements that are ±12% of standard game bat weight produce the greatest bat velocities for high school and intercollegiate players. The purpose of this study was to examine the effect of various warm-up devices on bat velocity (BV) of intercollegiate baseball players. Twenty-two Division I intercollegiate baseball players (age = 20.0 ± 1.5 years, height = 182.6 ± 8.3 cm, body mass = 91.4 ± 11.4 kg, lean body mass = 78.8 ± 8.9 kg, % body fat = 13.6 ± 3.8) participated in a warm-up with 1 of 10 weighted devices on separate days. Each of the 10 testing sessions consisted of a standardized warm-up, 3 dry swings as hard as possible with the assigned warm-up device, 2 comfortable dry swings with a standard game baseball bat followed by 3 game swings (20-second rest between swings) while hitting a baseball off of a batting tee with the same standard game baseball bat. Results indicated that there were no statistically significant differences in BV after using any of the 10 warm-up devices. For male intercollegiate baseball players, results indicate that warm-up devices varying from 623.7 to 2,721.5 g (22-96 oz.) did not change mean BV of a standard game baseball bat, suggesting that intercollegiate players can use any of the 10 warm-up devices in the on-deck circle and maintain their BV. Therefore, personal preference as to which warm-up implement to use in the on-deck circle is advised.     

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.     

Occlusion training increases muscular strength in division IA football players

The purpose of this study was to investigate the effectiveness of 4 weeks of low-intensity resistance training with blood-flow occlusion on upper and lower body muscular hypertrophy and muscular strength in National Collegiate Athletic Association Division IA football players. There were 32 subjects (average age 19.2 ± 1.8 years) who were randomized to an occlusion group or control group. The athletes performed 4 sets of bench press and squat in the following manner with or without occlusion: 30 repetitions of 20% predetermined 1 repetition maximum (1RM), followed by 3 sets of 20 repetitions at 20% 1RM. Each set was separated by 45 seconds. The training duration was 3 times per week, after the completion of regular off-season strength training. Data collected included health history, resting blood pressure, pretraining and posttraining bench press and squat 1RM, upper and lower chest girths, upper and lower arm girths, thigh girth, height, and body mass. The increases in bench press and squat 1RM (7.0 and 8.0%, respectively), upper and lower chest girths (3 and 3%, respectively), and left upper arm girth were significantly greater in the experiment group (p < 0.05). Occlusion training could provide additional benefits to traditional strength training to improve muscular hypertrophy and muscular strength in collegiate athletes.     

Changes in strength and power performance in elite senior female professional volleyball players during the in-season: a case study

It is often recommended that in-season training programs aim to maintain muscular strength and power developed during the off-season. However, improvements in performance may be possible with a well-designed training regimen. The purpose of this case report is to describe the changes in physical performance after an in-season training regimen in professional female volleyball players in order to determine whether muscular strength and power might be improved. Apart from normal practice sessions, 10 elite female volleyball players completed 2 training sessions per week, which included both resistance training and plyometric exercises. Over the 12-week season, the athletes performed 3-4 sets of 3-8 repetitions for resistance and plyometric exercises during each training session. All sessions were supervised by one of the investigators as well as by the team head coach. Muscular strength and power were assessed before and after the 12-week training program using 4 repetition maximum bench press and parallel squat tests, an overhead medicine ball throw (BTd), as well as unloaded and loaded countermovement jumps (CMJs). Strength improved by 15% and 11.5% in the bench press and parallel squat, respectively (p < 0.0001). Distance in the BTd improved by 11.8% (p < 0.0001), whereas unloaded and loaded CMJ height increased between 3.8 and 11.2%. The current findings suggest that elite female volleyball players can improve strength and power during the competition season by implementing a well-designed training program that includes both resistance and plyometric exercises.     

Comparison of trunk kinematics in trunk training exercises and throwing

Strength and conditioning professionals, as well as coaches, have emphasized the importance of training the trunk and the benefits it may have on sport performance and reducing the potential for injury. However, no data on the efficacy of trunk training support such claims. The purpose of this study was to examine the maximum differential trunk rotation and maximum angular velocities of the pelvis and upper torso of participants while they performed 4 trunk exercises (seated band rotations, cross-overs, medicine ball throws, and twisters) and compare these trunk exercise kinematics with the trunk kinematics demonstrated in actual throwing performance. Nine NCAA Division I baseball players participated in this study. Each participant's trunk kinematics was analyzed while he performed 5 repetitions of each exercise in both dominant and nondominant rotational directions. Results indicated maximum differentiated rotation in all 4 trunk exercises was similar to maximum differentiated rotation (approximately 50-60 degrees) demonstrated in throwing performance. Maximum angular velocities of the pelvis and upper torso in the trunk exercises were appreciably slower (approximately 50% or less) than the angular velocities demonstrated during throwing performance. Incorporating trunk training exercises that demonstrate sufficient trunk ranges of motion and velocities into a strength and conditioning program may help to increase ball velocity and/or decrease the risk injury.     

Comparison between linear and nonlinear in-season training programs in freshman football players

The purpose of this study was to compare linear (LT) with nonlinear (NL) in-season training programs in freshman football players during the course of 2 separate seasons. During the first year (n = 14, mean +/- SD = 177.3 +/- 4.8 cm, 88.0 +/- 9.7 kg), the LT program was employed 2 days per week. In the second year (n = 14, 175.0 +/- 7.1 cm, 94.2 +/- 20.5 kg), a 2 days per week LT was used. Subjects were tested for maximal strength in the squat (1 repetition maximum [1RM]) and bench press (1RM) exercises. A significant improvement in 1RM squat was seen in LT, but not in NL. No significant improvement in 1RM bench press was seen in either group. A significant difference between LT and NL was observed in Delta1RM squat (13.8 +/- 7.4 kg compared with 1.6 +/- 2.6 kg, respectively). Results of this study suggest that LT may be more effective in eliciting strength gains than NL in freshman football players during an in-season training program.     

Training leading to repetition failure enhances bench press strength gains in elite junior athletes

The purpose of this study was to investigate the importance of training leading to repetition failure in the performance of 2 different tests: 6 repetition maximum (6RM) bench press strength and 40-kg bench throw power in elite junior athletes. Subjects were 26 elite junior male basketball players (n = 12; age = 18.6 +/- 0.3 years; height = 202.0 +/- 11.6 cm; mass = 97.0 +/- 12.9 kg; mean +/- SD) and soccer players (n = 14; age = 17.4 +/- 0.5 years; height = 179.0 +/- 7.0 cm; mass = 75.0 +/- 7.1 kg) with a history of greater than 6 months' strength training. Subjects were initially tested twice for 6RM bench press mass and 40-kg Smith machine bench throw power output (in watts) to establish retest reliability. Subjects then undertook bench press training with 3 sessions per week for 6 weeks, using equal volume programs (24 repetitions x 80-105% 6RM in 13 minutes 20 seconds). Subjects were assigned to one of two experimental groups designed either to elicit repetition failure with 4 sets of 6 repetitions every 260 seconds (RF(4 x 6)) or allow all repetitions to be completed with 8 sets of 3 repetitions every 113 seconds (NF(8 x 3)). The RF(4 x 6) treatment elicited substantial increases in strength (7.3 +/- 2.4 kg, +9.5%, p < 0.001) and power (40.8 +/- 24.1 W, +10.6%, p < 0.001), while the NF(8 x 3) group elicited 3.6 +/- 3.0 kg (+5.0%, p < 0.005) and 25 +/- 19.0 W increases (+6.8%, p < 0.001). The improvements in the RF(4 x 6) group were greater than those in the repetition rest group for both strength (p < 0.005) and power (p < 0.05). Bench press training that leads to repetition failure induces greater strength gains than nonfailure training in the bench press exercise for elite junior team sport athletes.     

Effects of linear vs. daily undulatory periodized resistance training on maximal and submaximal strength gains

The objective of this study was to verify the effect of 2 periodized resistance training (RT) methods on the evolution of 1-repetition maximum (1RM) and 8RM loads. Twenty resistance trained men were randomly assigned to 2 training groups: linear periodization (LP) group and daily undulating periodization (DUP) group. The subjects were tested at baseline and after 12 weeks for 1RM and 8RM loads in leg press (LEG) and bench press (BP) exercises. The training program was performed in alternated sessions for upper (session A: chest, shoulder and triceps) and lower body (session B: leg, back and biceps). The 12-week periodized training was applied only in the tested exercises, and in the other exercises, 3 sets of 6-8RM were performed. Both groups exhibited significant increases in 1RM loads on LEG and BP, but no statistically significant difference between groups was observed. The same occurred in 8RM loads on LEG and BP. However, DUP group presented superior effect size (ES) in 1RM and 8RM loads for LEG and BP exercises when compared to the LP group. In conclusion, periodized RT can be an efficient method for increasing the strength and muscular endurance in trained individuals. Although there was no statistically significant difference between periodization models, DUP promoted superior ES gains in muscular maximal and submaximal strength.     

Effects of muscular strength, exercise order, and acute whole-body vibration exposure on bat swing speed

The purposes for this study were to investigate effects of acute whole-body vibration (WBV) exposure and exercise order on bat speed and to examine relationship between muscular strength and bat speed. All participants were recreationally trained men (n = 16; 22 ± 2 years; 181.4 ± 7.4 cm; 84.7 ± 9 kg), with previous baseball experience and were tested for 1 repetitive maximum (1RM) strength in squat and bench press. Subjects then participated in 4 randomized sessions on separate days, each consisting of 3 sets of 5 bat swings. Exercises (upper and lower body dynamic and static movements related to bat swing) with or without WBV exposure were performed after sets 1 and 2. Trials were as follows: no-exercise Control (CTRL), upper body followed by lower body exercises without WBV (Arm-Leg NOVIB), upper body followed by lower body exercises with WBV (Arm-Leg VIB), and lower body followed by upper body exercises with WBV (Leg-Arm VIB). Bat speed was recorded during each swing and averaged across sets. Statistical analyses were performed to assess differences across sets and trials. Linear regressions analyzed relationship between strength and bat speed. A significant relationship existed between bat speed and lower body strength (r = 0.406, p = 0.008) but not for upper body strength. The exercise order of Arm-Leg VIB significantly increased bat speed by 2.6% (p = 0.02). Performing identical order of exercises without vibration (Arm-Leg NOVIB) significantly decreased bat speed by 2% (p = 0.039). It was concluded that adding vibration exposure to total-body exercises can provide acute enhancements in bat speed. Additionally, leg strength was shown to influence bat speed suggesting that increasing leg strength may enhance bat speed.     

Effects of training with a dynamic moment of inertia bat on swing performance

The purpose of this study was to investigate the effects of the 8-week dynamic moment of inertia (DMOI) bat training on swing velocity, batted-ball speed, hitting distance, muscle power, and grip force. The DMOI bat is characterized in that the bat could be swung more easily by reducing the moment of inertia at the initial stage of swing without decreasing the bat weight and has a faster swing velocity and lower muscle activity. Seventeen varsity baseball players were randomly assigned to the DMOI bat training group (n = 9) and the normal bat training group (n = 8). The training protocol was 7 swings each set, 5-8 sets each time, 3 times each week, and 8 weeks' training period. The results showed that the swing training with the DMOI bat for 8 weeks significantly increased swing velocity by about 6.20% (96.86 ± 8.48 vs. 102.82 ± 9.93 km·h(-1)), hitting distance by about 6.69% (80.06 ± 9.16 vs. 84.99 ± 7.26 m), muscle power of the right arm by about 12.04% (3.34 ± 0.41 vs. 3.74 ± 0.61 m), and muscle power of the left arm by about 8.23% (3.36 ± 0.46 vs. 3.61 ± 0.39 m) (p < 0.05). Furthermore, the DMOI bat training group had a significantly better change percentage in swing velocity, hitting distance, and grip force of the left hand than did the normal bat training group (p < 0.05). The findings suggested that the swing training with the DMOI bat has a positive benefit on swing performance and that the DMOI bat could be used as a new training tool in baseball.