Resumen de Acute Postexercise Time Course Responses of Hypertrophic vs. Power-Endurance Squat Exercise Protocols on Maximal and Rapid Torque of the Knee Extensors

Eric C. Conchola, Ryan M. Thiele, Ty B. Palmer, Doug B. Smith, Brennan J. Thompson

• The aim of this study was to examine the effects of a medium-intensity high-volume vs. explosive squat protocol on the postexercise time course responses of maximal and rapid strength of the knee extensors. Seventeen resistance-trained men (mean ± SD: age = 22.0 ± 2.6 years) performed maximal voluntary contractions (MVCs) of the knee extensors before and after performing a squat workout using 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% 1RM) exercise protocol. For each MVC, peak torque (PT), peak rate of torque development (RTDpeak), absolute (RTDabs), and relative RTD (RTDnorm) at early (0–50 milliseconds) and late (100–200 milliseconds) phases of muscle contraction were examined at pre- (Pre) and post-exercise at 0, 7, 15, and 30 (Post0…30) minutes. There were no intensity × time interactions for any variables (p = 0.098–0.832). Peak torque was greater at Pre than Post0 and Post7 (p = 0.001–0.016) but was not greater than Post15 and Post30 (p = 0.010–0.189). RTDpeak and early absolute RTD (RTD50abs) were greater at Pre than all postexercise time phases (p = 0.001–0.050); however, later absolute RTD (RTD100–200abs) was only greater at Pre than Post0 and Post30 (p = 0.013–0.048). Early relative RTD (RTD50norm) was only higher at Pre compared with Post0 (p = 0.023), whereas no differences were observed for later relative RTD (RTD100–200norm) (p = 0.920–0.990). Low-intensity fast velocity and TISV squat protocols both yielded acute decreases in maximal and rapid strength capacities following free-weight squats, with rapid strength showing slower recovery characteristics than maximal strength.