EFFECTS OF DYNAMIC FATIGUE ON MAXIMAL AND RAPID VELOCITY CAPACITIES OF THE LEG EXTENSORS IN COLLEGE-AGED MALES
Eric C. Conchola1, Ryan M. Thiele1 & Garrett M. Hester1
1Oklahoma State University, Stillwater, Oklahoma
Declines in muscular strength and power are commonly reported post workout. However, few studies have investigated the influence of dynamic back squat protocols on maximal and rapid velocity characteristics post fatigue. PURPOSE: The purpose of this study was to examine the effects of a low-intensity, fast-velocity and a high-intensity,-slow-velocity squat protocol on the post-exercise time course responses on maximal and rapid velocity characteristics of the leg extensor muscles. METHODS: Sixteen resistance-trained college-aged (age=22.0±2.6years) men performed 3 isokinetic maximal voluntary contractions (MVCs) of the knee extensors pre- and post-exercise at 0,7,15, and 30 (Post0,…30) minutes after performing either a low-intensity, fast-velocity (LIFV) (5×16 at 40% 1-repetition maximum), or a traditional high-intensity, slow-velocity (TISV) (5 ×8 at 80% 1-RM) back squat exercise protocol. Maximal and rapid velocity variables were assessed on an isokinetic dynamometer. Participants performed three leg extension maximal voluntary contractions (MVCs) at 240° .s-1 and at maximum unloaded velocity (Vmax). Vmax was calculated as the highest velocity attained during the unloaded MVC and RVD was the linear slope of the velocity-time curve for the 240° .s-1 (RVD240) and maximum unloaded velocity (RVD-Vmax) contractions. Three separate two-way (2×5) repeated measures ANOVAs (intensity [TISV vs. LIFV] x time [Pre vs. Post0 vs. Post7 vs. Post15 vs. Post30]) were used to analyze all RVD and Vmax variables. RESULTS: For RVD240, there was no interaction for intensity × time (P=0.660), but there was a main effect for time in which RVD was lower at Post0 (P=0.001), no main effect for intensity was present (P=0.152). For RVD500, there was no interaction for intensity × time (P=0.544), but there was a main effect for time and intensity (P=0.024 – 0.047) in which RVD500 was decreased at Post0- Post15 (P=0.001-0.041), and the TISV was affected greater than the LIFV. For Vmax, there was no significant interaction for intensity × time (P=0.485), nor main effect for intensity (P=0.083), but there was a main effect for time (P=0.013) in which Vmax was lower at all post fatigue time phases (P=0.001-0.017). CONCLUSIONS: These findings suggests a dynamic free-weight squat protocol affects Vmax more than the RVD. Additionally, RVD240 observed similar fatigue responses for both intensities, while RVD500 observed similar responses for time, but TISV was affected more than the LISV protocol.
Conchola, EC; Thiele, RM; and Hester, GM
"EFFECTS OF DYNAMIC FATIGUE ON MAXIMAL AND RAPID VELOCITY CAPACITIES OF THE LEG EXTENSORS IN COLLEGE-AGED MALES,"
International Journal of Exercise Science: Conference Proceedings:
2, Article 11.
Available at: http://digitalcommons.wku.edu/ijesab/vol11/iss2/11
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