Journal of Strength and Conditioning Research, 2010
The purpose of this study is to determine the effectiveness of two baseball stealing techniques, ... more The purpose of this study is to determine the effectiveness of two baseball stealing techniques, cross-over step (CS) and jab step (JS) in Division-I baseball players on total distance traveled (meters, m), total time (seconds, s) and velocity (m/s) over the first two sprint strides. METHOD: Eight Division-I baseball players from the University of Northern Iowa volunteered for this study. Each subject attended one session and performed six total repetitions of (JS) and (CS), three for each technique. Technique assignment was assigned randomly to eliminate any order effect. RESULTS: The results of the Hotelling's T2 indicate that there was a significant treatment effect (F(7,1) = 958750, p<0.001) on at least one of the measurements. Post hoc analysis concluded that the jab step resulted in significantly greater distance traveled (t(7)=4.35, p=0.003), however it took significantly more total time (t(7)=4.64,p=0.002) to cover this distance resulting in no difference in overall sprint velocity over the first two strides. CONCLUSIONS: It appears that both techniques will produce similar results in initiating the baseball steal. PRACTICAL APPLICATION: CS or JS are appropriate to teach in initializing the baseball steal with neither showing an advantage over the other. Though it required less time to perform the first two strides during CS, the total distance was shorter than JS ending in both techniques resulting in nearly identical velocities.
Training efficiency is an important underlying concept of strength and conditioning. Minimal rese... more Training efficiency is an important underlying concept of strength and conditioning. Minimal research exists exploring the efficiency of traditionally practiced gripping techniques in comparisons to one another, yet grip efficiency could contribute to improved strength and conditioning performance. PURPOSE: The purpose of this study was to investigate the neuromuscular differences between three traditional grip techniques [hook (HG), regular (RG), and thumbless (TG)]. METHODS: The counterbalanced, within subjects design consisted of ten (21.9 ± 2.3 yrs., 175.8 ± 6.1 cm, 78.0 ± 9.9 kg) trained male subjects who were outfitted with EMG electrodes on the forearm flexor bundle. Subjects performed 1 maximum voluntary contraction (MVC) trial with an unloaded 20kg barbell. Following MVC recording, each subject performed 2 deadlift repetitions with a 60kg barbell utilizing all three grip techniques. RESULTS: Paired samples t-tests demonstrated a significant difference in EMG activity (MVC) between RG vs. TG (P=0.03). No significance was demonstrated for MVC between RG vs. HG (P=0.73) and between HG vs. TG (P=0.48). Paired samples t-tests also demonstrated a significant difference in additional EMG activity (% of MVC) during the deadlift movement between RG vs. TG (P=0.01). No significance was demonstrated for % of MVC during the deadlift movement between RG vs. HG (P=0.74) and between HG vs. TG (P=0.54). CONCLUSIONS: Results indicated the RG produced greater MVC and increased efficiency in the deadlift when compared to the TG. The results of this study suggest that HG may be an equivalent variation compared to RG. Future research will investigate the effects of HG versus RG in dynamic/Olympic weightlifting movements as well as differences in efficiency in a trained population.
RESULTS: The average peak ball speed for attackmen, defensemen, and midfielders was 69 mph, 64 mp... more RESULTS: The average peak ball speed for attackmen, defensemen, and midfielders was 69 mph, 64 mph, and 74 mph, respectively. The mean SL/H ratios were higher in the dominant side than the non-dominant side at FC irrespective of position (p<0.001). There was a strong correlation between SL/H ratio and ball speed in defensemen at BR (r=0.836, p<0.001), and low correlations for attackmen (BR r=0.16, p<0.001; ) and midfielders (BR r=0.22 , p<0.001 ) TL-ROM for attack was 20.6o±10.3o and 15.4o±8.2o for dominant and non-dominant sides, respectively and TL-ROM for defense was 20.6o±14.8o and 18.8o±13.0o for dominant and non-dominant sides, respectively. For midfield, TL-ROM was 16.4±7.4 and 15.2o±8.2o for dominant and non-dominant sides. CONCLUSION: SL/H ratios were not different by player position type. The TL-ROM in defensemen was more strongly associated to faster ball speed than in attackmen and midfielders. Defenders holding a long lever arm rely more on trunk lean to develop fast ball speeds than midfielders and attackmen who may use other strategies to develop speed including upper body rotation and more wrist motion.
The purpose of this study was to compare traditional and swing blocking techniques on center of m... more The purpose of this study was to compare traditional and swing blocking techniques on center of mass (COM) projectile motion and effective blocking area in nine healthy Division I female volleyball players. Two high-definition (1080 p) video cameras (60 Hz) were used to collect two-dimensional variables from two separate views. One was placed perpendicular to the plane of the net and the other was directed along the top of the net, and were used to estimate COM locations and blocking area in a plane parallel to the net and hand penetration through the plane of the net respectively. Video of both the traditional and swing techniques were digitized and kinematic variables were calculated. Paired samples t-tests indicated that the swing technique resulted in greater (p < 0.05) vertical and horizontal takeoff velocities (vy and vx), jump height (H), duration of the block (tBLOCK), blocking coverage during the block (C) as well as hand penetration above and through the net's plane...
The purpose was to determine if glutamine supplementation would prevent a loss of lean mass in at... more The purpose was to determine if glutamine supplementation would prevent a loss of lean mass in athletes during a 12-day weight reduction program. It was hypothesized that supplementation would spare lean body mass. Subjects (n=18) exercised and dieted to create a 4186kJ·day(-1) energy deficit and a 8372 kJ·day(-1) energy deficit on days 1-5, days 6-12, respectively. The glutamine (GLN) group (n=9) ingested 0.35 g·kg(-1) body mass of glutamine while a placebo was administered to the remaining subjects. Body mass (BM), lean body mass (LBM) and fat mass (FM), were measured at days 0, 6, and 12. GLN and placebo groups both lost significant amounts of BM, LBM and FM. There were no significant differences between groups. The findings indicate little benefit for retention of lean mass with supplementation of glutamine during a short-term weight reduction program.
The purpose of this study was to determine the optimal load for power during concentric only (CO)... more The purpose of this study was to determine the optimal load for power during concentric only (CO) and stretch-shortening cycle (SSC) leg-press movements during the initial portion of the concentric phase as well as throughout the entire concentric phase in trained female rowers. Thirty female rowers (age = 19.6 +/- 1.2 yr) were tested for strength (1RM), mean power (MP), peak power (PP), as well as power output at 50, 100, 150, and 200 ms (P50-P200) during both CO and SSC leg-press movements and across six different loads (30-80% 1RM) on the Omnikinetic dynamometer. Split-split plot analysis indicated that MP and PP were maximized at approximately 60% 1RM in both CO and SSC movements. There were no significant differences in P50 and P100 across all loads for both CO and SSC. P150 was greatest at 30, 40, 50, and 60% 1RM for CO and SSC movements. P200 was maximized at 30, 40, and 50% 1RM during CO. P200 was maximized at 50, 60, and 70% 1RM during SSC. There was no difference in the optimal loads for MP (40, 50, and 60% 1RM) and PP (50, 60, and 70% 1RM) between CO and SSC movements. An enhancement of power during the initial 200 ms of the concentric phase of SSC movements was observed. Greater time to reach PP was the reason for the enhancement in PP output observed in CO movements. The CO training regimen associated with the sport of rowing also may have lessened the effect of the SSC.
Medicine & Science in Sports & Exercise, 2004
Squat exercise variations are considered a cornerstone of resistance training (RT) programs. Unde... more Squat exercise variations are considered a cornerstone of resistance training (RT) programs. Understanding the effectiveness of differing squat exercise variations is important for coaches and athletes in order to optimizing the effectiveness of a RT program. Purpose: The current investigation examined a comparison of the standard Olympic barbell loaded back squat (BS) with a squat performed with the safety squat bar (SSB). Methods: Twenty eight Division I male baseball players (19.2±1.1 years, 182.5±5.6 cm, 87.6±5.1 kg) participated in a RT program comprised of two workout sessions a week for nine weeks, performing either a BS or SSB utilizing an autoregulatory progressive resistance periodization, concurrent with their existing, season-specific, resistance training program. Pitchers (n=14) utilized the SSB bar with the goal of minimizing stress on the shoulder and elbow joints during the execution of the squat. The non-pitchers (n=14) performed the Olympic barbell BS. Lower body strength (estimated 1RM squat), sprint speed (54.86 m sprint), and vertical jump (VJ cms) were assessed prior to and following the RT training period. Results: Both the VJ and estimated 1RMs had a significant positive improvement from pre-training to post-training for both the BS and SSB groups (p<0.05). When comparing gain scores between each group there were no significant differences between the BS and SSB groups for either 54.86 m sprint or VJ (p>0.05). However, the 1RM squat gain score for the SSB was significantly greater than the BS group (p<0.05) noting that the effect size of change from pre to post RT was 2.69 and 2.71 standard deviations for the BS and SSB groups respectively. Discussion: Given that both squat modalities yielded approximately equal improvements in VJ and lower body strength, coaches and athletes can consider the SSB variation of the squat as a viable option for developing lower body strength and power when an Olympic barbell may be contraindicated because of an upper body injury.
Journal of Strength and Conditioning Research, 2014
The purpose of this study was to compare the track block start (BS), rhythm step (false step) (RS... more The purpose of this study was to compare the track block start (BS), rhythm step (false step) (RS), and forward step (FS) on sprint start ability in male Division I collegiate football linebackers. Although the blocks are not practical in the sport of football, they were used as a gold standard for sprint acceleration. Sixteen collegiate football linebackers (age, 20.9 ± 1.1 years; height, 72 ± 3.0 in; mass, 97 ± 4 kg) performed 3 repetitions each of the BS, FS, and RS. Each sprint was videotaped through 5 m. The time from 0 to 2.5 m (t2.5), 0 to 5 m (t5), and 2.5 to 5 m (tsplit) were calculated for each trial using all 3 different techniques, and the best times for each treatment was recorded. Block start resulted in significantly lower t2.5 and t5 compared with RS and FS. Rhythm step had significantly lower t2.5 and t5 compared with FS. There was no difference in tsplit between any of the 3 treatments. The results indicate that using the blocks is optimal for sprint performance through 2.5 and 5 m. Rhythm step outperformed FS through both 2.5 and 5 m, suggesting that for collegiate football linebackers, RS is superior to FS.
Journal of Strength and Conditioning Research, 2012
The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-sho... more The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-shortening cycle performance in female Division I soccer players and female club rugby players. Fifteen soccer and rugby players (20.1 ± 5.9 years, 170.5 ± 14.2 cm, 70.4 ± 22.3 kg) participated in 3 test sessions with different treatments. The first treatment involved a warm-up of 10 minutes of exercise on a cycle ergometer (warm-up only [WO]), the second was this warm-up followed by static stretching (SS), and the third was this warm-up followed by dynamic stretching (DS). The treatments were administered randomly to negate an order effect. Each treatment was immediately followed by a reactive strength index (RSI) test requiring the athletes to drop off a box (45 cm in height) on to a force plate and upon landing immediately jump into the air while minimizing contact time (CT, milliseconds) and maximizing flight time (FT, milliseconds). The RSI was FT: CT. Repeated measures analysis of variance indicated that a significant treatment effect existed for RSI (F = 7.95, 2; p = 0.002) and FT (F = 7.43, 2; p = 0.003) but no significant effect for CT (F = 1.53, 2; p = 0.235). The RSI and FT were significantly greater in DS compared with that in SS and WO. Dynamic stretching is the preferred warm-up before an athletic event involving considerable jumping.
Journal of Strength and Conditioning Research, 2010
The purpose of this study is to determine the effectiveness of two baseball stealing techniques, ... more The purpose of this study is to determine the effectiveness of two baseball stealing techniques, cross-over step (CS) and jab step (JS) in Division-I baseball players on total distance traveled (meters, m), total time (seconds, s) and velocity (m/s) over the first two sprint strides. METHOD: Eight Division-I baseball players from the University of Northern Iowa volunteered for this study. Each subject attended one session and performed six total repetitions of (JS) and (CS), three for each technique. Technique assignment was assigned randomly to eliminate any order effect. RESULTS: The results of the Hotelling's T2 indicate that there was a significant treatment effect (F(7,1) = 958750, p<0.001) on at least one of the measurements. Post hoc analysis concluded that the jab step resulted in significantly greater distance traveled (t(7)=4.35, p=0.003), however it took significantly more total time (t(7)=4.64,p=0.002) to cover this distance resulting in no difference in overall sprint velocity over the first two strides. CONCLUSIONS: It appears that both techniques will produce similar results in initiating the baseball steal. PRACTICAL APPLICATION: CS or JS are appropriate to teach in initializing the baseball steal with neither showing an advantage over the other. Though it required less time to perform the first two strides during CS, the total distance was shorter than JS ending in both techniques resulting in nearly identical velocities.
Training efficiency is an important underlying concept of strength and conditioning. Minimal rese... more Training efficiency is an important underlying concept of strength and conditioning. Minimal research exists exploring the efficiency of traditionally practiced gripping techniques in comparisons to one another, yet grip efficiency could contribute to improved strength and conditioning performance. PURPOSE: The purpose of this study was to investigate the neuromuscular differences between three traditional grip techniques [hook (HG), regular (RG), and thumbless (TG)]. METHODS: The counterbalanced, within subjects design consisted of ten (21.9 ± 2.3 yrs., 175.8 ± 6.1 cm, 78.0 ± 9.9 kg) trained male subjects who were outfitted with EMG electrodes on the forearm flexor bundle. Subjects performed 1 maximum voluntary contraction (MVC) trial with an unloaded 20kg barbell. Following MVC recording, each subject performed 2 deadlift repetitions with a 60kg barbell utilizing all three grip techniques. RESULTS: Paired samples t-tests demonstrated a significant difference in EMG activity (MVC) between RG vs. TG (P=0.03). No significance was demonstrated for MVC between RG vs. HG (P=0.73) and between HG vs. TG (P=0.48). Paired samples t-tests also demonstrated a significant difference in additional EMG activity (% of MVC) during the deadlift movement between RG vs. TG (P=0.01). No significance was demonstrated for % of MVC during the deadlift movement between RG vs. HG (P=0.74) and between HG vs. TG (P=0.54). CONCLUSIONS: Results indicated the RG produced greater MVC and increased efficiency in the deadlift when compared to the TG. The results of this study suggest that HG may be an equivalent variation compared to RG. Future research will investigate the effects of HG versus RG in dynamic/Olympic weightlifting movements as well as differences in efficiency in a trained population.
RESULTS: The average peak ball speed for attackmen, defensemen, and midfielders was 69 mph, 64 mp... more RESULTS: The average peak ball speed for attackmen, defensemen, and midfielders was 69 mph, 64 mph, and 74 mph, respectively. The mean SL/H ratios were higher in the dominant side than the non-dominant side at FC irrespective of position (p<0.001). There was a strong correlation between SL/H ratio and ball speed in defensemen at BR (r=0.836, p<0.001), and low correlations for attackmen (BR r=0.16, p<0.001; ) and midfielders (BR r=0.22 , p<0.001 ) TL-ROM for attack was 20.6o±10.3o and 15.4o±8.2o for dominant and non-dominant sides, respectively and TL-ROM for defense was 20.6o±14.8o and 18.8o±13.0o for dominant and non-dominant sides, respectively. For midfield, TL-ROM was 16.4±7.4 and 15.2o±8.2o for dominant and non-dominant sides. CONCLUSION: SL/H ratios were not different by player position type. The TL-ROM in defensemen was more strongly associated to faster ball speed than in attackmen and midfielders. Defenders holding a long lever arm rely more on trunk lean to develop fast ball speeds than midfielders and attackmen who may use other strategies to develop speed including upper body rotation and more wrist motion.
The purpose of this study was to compare traditional and swing blocking techniques on center of m... more The purpose of this study was to compare traditional and swing blocking techniques on center of mass (COM) projectile motion and effective blocking area in nine healthy Division I female volleyball players. Two high-definition (1080 p) video cameras (60 Hz) were used to collect two-dimensional variables from two separate views. One was placed perpendicular to the plane of the net and the other was directed along the top of the net, and were used to estimate COM locations and blocking area in a plane parallel to the net and hand penetration through the plane of the net respectively. Video of both the traditional and swing techniques were digitized and kinematic variables were calculated. Paired samples t-tests indicated that the swing technique resulted in greater (p < 0.05) vertical and horizontal takeoff velocities (vy and vx), jump height (H), duration of the block (tBLOCK), blocking coverage during the block (C) as well as hand penetration above and through the net's plane...
The purpose was to determine if glutamine supplementation would prevent a loss of lean mass in at... more The purpose was to determine if glutamine supplementation would prevent a loss of lean mass in athletes during a 12-day weight reduction program. It was hypothesized that supplementation would spare lean body mass. Subjects (n=18) exercised and dieted to create a 4186kJ·day(-1) energy deficit and a 8372 kJ·day(-1) energy deficit on days 1-5, days 6-12, respectively. The glutamine (GLN) group (n=9) ingested 0.35 g·kg(-1) body mass of glutamine while a placebo was administered to the remaining subjects. Body mass (BM), lean body mass (LBM) and fat mass (FM), were measured at days 0, 6, and 12. GLN and placebo groups both lost significant amounts of BM, LBM and FM. There were no significant differences between groups. The findings indicate little benefit for retention of lean mass with supplementation of glutamine during a short-term weight reduction program.
The purpose of this study was to determine the optimal load for power during concentric only (CO)... more The purpose of this study was to determine the optimal load for power during concentric only (CO) and stretch-shortening cycle (SSC) leg-press movements during the initial portion of the concentric phase as well as throughout the entire concentric phase in trained female rowers. Thirty female rowers (age = 19.6 +/- 1.2 yr) were tested for strength (1RM), mean power (MP), peak power (PP), as well as power output at 50, 100, 150, and 200 ms (P50-P200) during both CO and SSC leg-press movements and across six different loads (30-80% 1RM) on the Omnikinetic dynamometer. Split-split plot analysis indicated that MP and PP were maximized at approximately 60% 1RM in both CO and SSC movements. There were no significant differences in P50 and P100 across all loads for both CO and SSC. P150 was greatest at 30, 40, 50, and 60% 1RM for CO and SSC movements. P200 was maximized at 30, 40, and 50% 1RM during CO. P200 was maximized at 50, 60, and 70% 1RM during SSC. There was no difference in the optimal loads for MP (40, 50, and 60% 1RM) and PP (50, 60, and 70% 1RM) between CO and SSC movements. An enhancement of power during the initial 200 ms of the concentric phase of SSC movements was observed. Greater time to reach PP was the reason for the enhancement in PP output observed in CO movements. The CO training regimen associated with the sport of rowing also may have lessened the effect of the SSC.
Medicine & Science in Sports & Exercise, 2004
Squat exercise variations are considered a cornerstone of resistance training (RT) programs. Unde... more Squat exercise variations are considered a cornerstone of resistance training (RT) programs. Understanding the effectiveness of differing squat exercise variations is important for coaches and athletes in order to optimizing the effectiveness of a RT program. Purpose: The current investigation examined a comparison of the standard Olympic barbell loaded back squat (BS) with a squat performed with the safety squat bar (SSB). Methods: Twenty eight Division I male baseball players (19.2±1.1 years, 182.5±5.6 cm, 87.6±5.1 kg) participated in a RT program comprised of two workout sessions a week for nine weeks, performing either a BS or SSB utilizing an autoregulatory progressive resistance periodization, concurrent with their existing, season-specific, resistance training program. Pitchers (n=14) utilized the SSB bar with the goal of minimizing stress on the shoulder and elbow joints during the execution of the squat. The non-pitchers (n=14) performed the Olympic barbell BS. Lower body strength (estimated 1RM squat), sprint speed (54.86 m sprint), and vertical jump (VJ cms) were assessed prior to and following the RT training period. Results: Both the VJ and estimated 1RMs had a significant positive improvement from pre-training to post-training for both the BS and SSB groups (p<0.05). When comparing gain scores between each group there were no significant differences between the BS and SSB groups for either 54.86 m sprint or VJ (p>0.05). However, the 1RM squat gain score for the SSB was significantly greater than the BS group (p<0.05) noting that the effect size of change from pre to post RT was 2.69 and 2.71 standard deviations for the BS and SSB groups respectively. Discussion: Given that both squat modalities yielded approximately equal improvements in VJ and lower body strength, coaches and athletes can consider the SSB variation of the squat as a viable option for developing lower body strength and power when an Olympic barbell may be contraindicated because of an upper body injury.
Journal of Strength and Conditioning Research, 2014
The purpose of this study was to compare the track block start (BS), rhythm step (false step) (RS... more The purpose of this study was to compare the track block start (BS), rhythm step (false step) (RS), and forward step (FS) on sprint start ability in male Division I collegiate football linebackers. Although the blocks are not practical in the sport of football, they were used as a gold standard for sprint acceleration. Sixteen collegiate football linebackers (age, 20.9 ± 1.1 years; height, 72 ± 3.0 in; mass, 97 ± 4 kg) performed 3 repetitions each of the BS, FS, and RS. Each sprint was videotaped through 5 m. The time from 0 to 2.5 m (t2.5), 0 to 5 m (t5), and 2.5 to 5 m (tsplit) were calculated for each trial using all 3 different techniques, and the best times for each treatment was recorded. Block start resulted in significantly lower t2.5 and t5 compared with RS and FS. Rhythm step had significantly lower t2.5 and t5 compared with FS. There was no difference in tsplit between any of the 3 treatments. The results indicate that using the blocks is optimal for sprint performance through 2.5 and 5 m. Rhythm step outperformed FS through both 2.5 and 5 m, suggesting that for collegiate football linebackers, RS is superior to FS.
Journal of Strength and Conditioning Research, 2012
The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-sho... more The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-shortening cycle performance in female Division I soccer players and female club rugby players. Fifteen soccer and rugby players (20.1 ± 5.9 years, 170.5 ± 14.2 cm, 70.4 ± 22.3 kg) participated in 3 test sessions with different treatments. The first treatment involved a warm-up of 10 minutes of exercise on a cycle ergometer (warm-up only [WO]), the second was this warm-up followed by static stretching (SS), and the third was this warm-up followed by dynamic stretching (DS). The treatments were administered randomly to negate an order effect. Each treatment was immediately followed by a reactive strength index (RSI) test requiring the athletes to drop off a box (45 cm in height) on to a force plate and upon landing immediately jump into the air while minimizing contact time (CT, milliseconds) and maximizing flight time (FT, milliseconds). The RSI was FT: CT. Repeated measures analysis of variance indicated that a significant treatment effect existed for RSI (F = 7.95, 2; p = 0.002) and FT (F = 7.43, 2; p = 0.003) but no significant effect for CT (F = 1.53, 2; p = 0.235). The RSI and FT were significantly greater in DS compared with that in SS and WO. Dynamic stretching is the preferred warm-up before an athletic event involving considerable jumping.
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