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Background: Youth populations benefit from neuromuscular training; however, the extent to which training frequency, baseline fitness, and maturity status moderate the response to long-term neuromuscular training in male youth remains unclear.Hypothesis: Twice-weekly training (G2x) would induce larger improvements in movement competency and strength and power kinetics compared with once-weekly training (G1x). Maturity status and baseline fitness would also moderate the training response in strength and power kinetics.Study Design: Nonrandomized, repeated-measures design.Level Of Evidence: Level 3.Methods: Ninety-five male athletes of varying maturity status (pre- or post-peak height velocity) were divided into G2x, G1x, or control (CON) groups. Training groups received G2x or G1x for 28 weeks. Back squat assessment (BSA) movement competency and isometric mid-thigh pull (IMTP), squat jump (SJ), and countermovement jump (CMJ) kinetics were measured pre- and postintervention.Results: The G2x achieved significantly greater adaptations in BSA total score, IMTP allometrically scaled peak force (PFallo), IMTP peak rate-of-force development (PRFD), SJ PFallo and PRFD compared with G1x and CON (P < 0.05; d = 0.3-0.9). Baseline fitness, training frequency and maturity status were significant predictors of IMTP PFallo (R2 = 27.5%) and PRFD (R2 = 42.9%), while a combination of training frequency and baseline fitness explained a small amount of variance in SJ PFallo (R2 = 12.2%) and SJ PRFD (R2 = 6.5%). There were no significant predictors of CMJ kinetics.Conclusion: G2x achieved significantly larger improvements in movement competency, isometric strength and concentric jump variables compared with G1x, with the training response greater in those youth with lower baseline fitness and more advanced maturity status.Clinical Relevance: Exposure to neuromuscular training twice-weekly elicits a greater response than G1x in young male athletes. Practitioners should take maturity status, training frequency, and baseline fitness levels of young male athletes into account when interpreting testing data, as these variables appear to moderate training responsiveness. [ABSTRACT FROM AUTHOR]

The back-squat assessment (BSA) is a novel movement screen to detect functional deficits; however, its sensitivity to detect meaningful changes in movement competency after exposure to short-term neuromuscular training remains unclear. Twenty-six pre– and 22 post–peak height velocity (PHV) males were divided into experimental (EXP) and control groups (CON) and performed the BSA before and after a twice weekly, 4-week neuromuscular training intervention. Intra-rater reliability was determined by rating both EXP group’s baseline BSA on 3 separate sessions. Intraclass correlation coefficient (ICC) revealed very strong agreement for BSA total score in pre-PHV (ICC > 0.81) and post-PHV (ICC> 0.97) groups across all sessions, but systematic bias was evident in the pre-PHV group for sessions 1–2. Analysis of kappa values for BSA individual criteria showed greater variability for pre-PHV (K ≥ 0.31) than post-PHV (K ≥ 0.62) across sessions. At baseline, there were no differences in total score between the EXP and CON cohorts (p .0.05). There were significant within-group improvements in total score for the EXP pre-PHV (5.0 to 3.0, effect size [ES] = 0.68) and post-PHV (2.0 to 1.0, ES = 0.82) cohorts, with no changes in total score for either CON groups (p .0.05). Hip position was the criterion with the greatest improvement for both the EXP pre-PHV (12.0 to 7.0) and post-PHV (7.0 to 0.0) groups. The BSA seems to be a reliable screening tool for measuring movement competency in youth male athletes and was sensitive to adaptations in movement competency after neuromuscular training. [ABSTRACT FROM AUTHOR]

Softball and baseball are games that require multiple skill sets such as throwing, hitting and fielding. Players spend a copious amount of time in batting practice in order to be successful hitters. Variables commonly associated with successful hitting include bat velocity and torso rotation. The concept of overspeed bodyweight assistance (BWA) has shown increases in vertical jump and sprint times, but not hip rotation and batting. The purpose of this study was to examine the effects of assisted hip rotation on bat velocity. Twenty-one male and female recreational softball and baseball players (15 males, age 23.8 ± 3.1yrs; height 177.67 ± 6.71cm; body mass 85.38 ± 14.83kg; 6 females, age 21.5 ± 2.1yrs; height 162.20 ± 9.82cm; body mass 60.28 ± 9.72kg) volunteered to participate. Four different BWA conditions (0%, 10%, 20%, and 30%) were randomly applied and their effects on bat velocity were analyzed. Subjects performed three maximal effort swings under each condition in a custom measurement device and average bat velocity (MPH) was used for analysis. A mixed factor ANOVA revealed no interaction (p=0.841) or main effect for condition, but there was a main effect for sex where males had greater bat velocity (43.82±4.40 - 0% BWA, 41.52±6.09 - 10% BWA, 42.59±7.24 - 20% BWA, 42.69±6.42 - 30% BWA) than females (32.57±5.33 - 0% BWA, 31.69±3.40 - 10% BWA, 32.43±5.06 - 20% BWA, 32.08±4.83 - 30% BWA) across all conditions Using the concept of overspeed training with assisted hip rotation up to 30% BWA did not result in an increase in bat velocity. Future research should examine elastic band angle and hip translation at set-up. [ABSTRACT FROM AUTHOR]

Rugby union requires players to demonstrate horizontal pushing force in activities such as a scrum, ruck, and tackle. Sprinting is also vital for players on offense and defense. Both horizontal pushing force and sprinting require producing maximal force with a forward body lean. Therefore, a relationship between horizontal pushing force and sprint speed may exist for rugby players. Nineteen collegiate rugby players (age= 22.4± 2.6 yrs; height= 178.3 ± 6.5cm; mass= 93.9 ± 20.6kg) performed an isometric maximal horizontal push test (MHPT) by pushing into a safety-squat bar with feet hipwidth apart and knees bent at 90±, both bilaterally and unilaterally. They performed a 30m sprint with splits at 5m, 10m, 15m, and 30m. Bilateral relative delta force (force- body weight÷body weight)) had a moderate negative correlation with split 1 (r=-0.56), split 2 (r=-0.52), split 3 (r=-0.51), split 4 (r=-0.47), and total time (r=-0.53). Dominant leg relative delta force had a moderate negative correlation with split 1 (r=-0.51), split 2 (r=-0.59), split 3 (r=-0.56), split 4 (r=-0.51), and total time (r=-0.53) while non-dominant leg relative delta force had a moderate negative correlation only with split 1 (r=- 0.58). Dominant leg rate of force development (RFD) was significantly greater (915.75 ± 664.77 Nm/s) than the nondominant leg (632.82 ± 435.40 Nm/s) but the non-dominant leg RFD at 250ms was significantly greater (1867.35 ± 663.78 Nm/s) than the dominant leg (1682.02 ± 619.23 Nm/s). The negative relationships between MHPT and sprinting may be due to similarities of forward lean and plantar flexion. These findings suggest that horizontal force production aids in sprinting. Therefore, rugby athletes should train in the horizontal direction to increase sprint speed. [ABSTRACT FROM AUTHOR]

Plyometric exercise is popular in commercial exercise programs aiming to maximize energy expenditure for weight loss. However, the effect of plyometric exercise on blood glucose is unknown. The purpose of this study was to investigate the effect of relatively high intensity plyometric exercise on blood glucose. Thirteen subjects (6 females age= 21.8 ± 1.0 yrs.; height= 163.7 ± 7.8 cm; mass= 60.8 ± 6.7 kg and 7 males age= 22.0 ± 2.6 yrs.; height= 182.3 ± 3.6 cm; mass= 87.4 ± 12.5 kg) volunteered to participate. Subjects completed two random conditions on two separate days, consisting of either five sets of 10 maximal effort countermovement squat jumps (SJ) with 50 seconds' rest between sets or quiet sitting (SIT) for the time equated to the SJ duration (~4min). Immediately after each condition, subjects drank 75g of anhydrous glucose (CHO) in 100ml of water. Blood glucose measurements were taken via finger prick pre and immediately post SJ or SIT, and 5, 15, 30, and 60 min post. A 2x6 (condition x time) ANOVA revealed a significant interaction where SJ blood glucose was lower at 15 (114.0 ± 14.6 mg/dl) and 30 (142.1 ± 22.5 mg/dl) min compared to SIT (15min 130.8 ± 14.0 mg/dl and 30min 159.3 ± 21.0 mg/dl). The current plyometric protocol attenuated CHO-induced blood glucose at 15 and 30 min. This may be due to increased physiological stress applied to the muscles, thus increasing muscular glucose uptake. [ABSTRACT FROM AUTHOR]