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Cameron S. Mackey, Garrett M. Hester, Zachary K. Pope, Frank M. Benik, and Jason M. DeFreitas. Oklahoma State University, Stillwater, OK; e-mail: cameron.mackey@okstate.edu

It has been suggested that regardless of contraction velocity, the intent to contract in a ballistic manner during resistance training (RT) is responsible for the training-related increase in rate of torque development (RTD). However, little evidence exists regarding the effects of low-velocity RT involving a ballistic-intent on RTD. Furthermore, it is unknown whether or not low-velocity RT performed with a ballistic-intent increases RTD of the contralateral limb during the early-phase (i.e., ≤4 weeks) of training. PURPOSE: To examine the short-term maximal and rapid-strength adaptations of the trained and untrained knee extensors during 4 weeks of unilateral isokinetic RT performed with a ballistic intent. METHODS: Twenty-three healthy, college-aged males who had not performed RT within the past 6 months volunteered to participate in this study. A training group (TG; n = 14, age = 22 ± 1.89 yrs., body mass = 80.42 ± 14.21 kg) performed 3 sessions per week of unilateral isokinetic RT of the dominant leg for 4 weeks and 3 testing sessions. The control group (CG; n = 9, age = 23 ± 4.30 yrs., body mass = 88.71 ± 17.61 kg) only participated in the testing. RT sessions consisted of maximal concentric contractions of the knee extensors at 45°·s-1 for 4 sets of 10 repetitions with 2-3 s of rest between repetitions and a 2 min rest between sets. During each RT session, subjects were instructed to “kick out as hard and fast as possible”. Subjects performed two maximal voluntary isometric contractions (MVCs) of the knee extensors for the trained (TL) and untrained (UL) leg before (pre), at week 2 (mid), and after week 4 (post) of RT. Maximal strength (peak torque; PT) as well as RTD at its peak (RTDPK), at 30 ms (RTD0-30), and at 200 ms (RTD0-200) after the onset of contraction were recorded for subsequent analysis. Independent-samples t-testes were used to compare all dependent variables at pre for the TG and CG. One-way repeated measures ANOVAs were used to compare all dependent variables at pre, mid, and post for the TL and UL in the TG and CG. RESULTS: There were no differences between the TG and CG at pre (p > 0.05). All dependent variables remained unchanged at mid and post for both legs in the CG (p > 0.05). For the TG, there was a significant increase in PT from pre to post (p = 0.001) and mid to post (p = 0.021) for the TL, while no differences were found for the UL across time (p = 0.070). All RTD measures remained unchanged for the TL and UL (p > 0.05). CONCLUSION: The results of the present study revealed that short-term, low-velocity RT performed with a ballistic intent led to an increase in PT of the TL but not the UL. In addition, all RTD measures for the TL and UL remained unchanged during the 4 week training protocol.

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