High intensity, near maximal exercise is a conditioning activity which can cause neural hyper-stimulation and lead to acute enhanced power production known as post-activation potentiation (PAP). Investigations need to be conducted to better understand the duration and intensity of the conditioning activity and subsequent effects on the fatigue-potentiation relationship. Purpose: To investigate the effect of 30 seconds of continuous vertical jumping while wearing a vest loaded with 30% of body weight on power output as measured with a maximal vertical jump (VJ). Methods: 14 volunteers (8 weight trained males [23.0+2.9 yrs, 79.8+13.8 kg, 179.9+8.6 cm] and 6 weight trained females [23.0+2.9 yrs, 69.9+13.3 kg, 171.6+7.0 cm]) participated in the study. Pre-testing consisted of each participant performing 3 VJs. The highest VJ was recorded as baseline. A weighted vest was then loaded equaling 30% of the individual's body weight; while wearing the weighted vest, participants performed ...

The purpose of this study was to determine the effects of a post activation potentiation (PAP) warm-up on sprint speed, with an emphasis on the role of specificity regarding the preparatory conditioning activity. It was hypothesized that a unilateral conditioning activity (barbell lunge) would provide a greater PAP effect on short sprint ability then a bilateral conditioning activity (barbell back squat). Sixteen NCAA Track Athletes participated (7 males, 9 females) in the study. The experiment employed a repeated measures crossover design where, following a familiarization session, each subject completed a randomly assigned warm-up (WU) on three different days with at least 48 hours between sessions. Following the randomly assigned WU, sprint speed was tested over a distance of 36.6 meters as well as quartiles. The WU's were: a dynamic, a dynamic followed by a unilateral barbell lunge (BL), and a dynamic followed by a bilateral back squat (BS). A repeated measures ANOVA was utilized to determine if there were significant differences between sprint times for each WU strategy. There were no statistically significant differences in sprint times between WU conditions at 36.6 m or any quartile (p>0.05). Within the parameters of this study, neither an intense bilateral or unilateral conditioning activity improved short sprint performance beyond that of a dynamic WU activity.

A prior conditioning resistance exercise can augment subsequent performance of the affected muscles due to the effects of post-activation potentiation (PAP). The non-local muscle fatigue literature has illustrated the global neural effects of unilateral fatigue. However, no studies have examined the possibility of acute non-local performance enhancements. The objective of the study was to provide a conditioning stimulus in an attempt to potentiate the subsequent jump performance of the affected limb and determine if there were performance changes in the contralateral limb. Using a randomized allocation, 14 subjects (6 females, 8 males) completed three conditions on separate days: 1) unilateral, dominant leg, Bulgarian split squat protocol with testing of the exercised leg, 2) unilateral, dominant leg, Bulgarian split squat protocol with testing of the contralateral, non-exercised leg and 3) control session with testing of the non-dominant leg. Pre- and post-testing consisted of coun...

, 2016). Effects of the trap bar deadlift and leg press on adolescent male strength, power and speed. ABSTRACT This study compared two lower body leg lifts, the trap bar deadlift (TBDL) and the leg press (LP), relative to their contributions to strength (6-RM leg strength), power (vertical jump-VJ height), and speed (36.6 meter-36.6MS) in adolescent males. Adolescent males (n=51; 13-15 years) were separated into two groups (TBDL group and LP group) via a matched pair design based on initial VJ height. Periodized resistance training was performed for 8-weeks (2x/wk) and focused on the primary exercises of the TBDL or the LP with supplemental lower body resistance training exercises (lunges, hamstring curls, calf raises, etc.) held equal between the study groups. Pre-and post-tests were conducted for 6-RM leg strength in TBDL or LP, VJ height, and 36.6MS. Both groups improved their lower body leg strength. The TBDL group improved the TBDL 6-RM by 21% (p<0.01) and the LP group improved the LP 6-RM by 19.7% (p<0.01). Despite improved strength, neither group demonstrated meaningful improvements in VJ height or 36.6MS times. The results of this study are consistent with previous literature in that lower body strength will improve when following a periodized strength training protocol in a population of adolescent males. While strength is a corner stone of power and speed, exercise protocols should include plyometrics and Olympic lift variations in order to facilitate the transfer of newly acquired strength to the attributes of power and speed. Within the parameters of this study TBDL and LP appear to be interchangeable modalities to increase lower body strength.