Gael Guilhem, Christophe Cornu, Arnaud Guével

Context: Resistance exercise training commonly is performed against a constant external ioad (isotonic) or at a constant velocity (isokinetic). Researchers comparing the effectiveness of isotonic and isokinetic resistance-training protocols need to equalize the mechanical stimulus (work and velocity) applied.

Objective: To examine whiether the standardization protocol could be adjusted and applied to an eccentric training program.

Design: Controlled laboratory study.

Setting: Controlled research laboratory. Patients or Other Participants: Twenty-one sport science male students (age = 20.6±1.5 years, height = 178.0 ±4.0 cm, mass = 74.5 ±9.1 kg).

Intervention(s): Participants performed 9 weeks of isotonic (n = 11 ) or isokinetic (n = 10) eccentric training of knee extensors that was designed so they would perform the same amount of angular work at the same mean angular velocity.

Main Outcome Measure(s): Angular work and angular velocity.

Results: The isotonic and isokinetic groups performed the same total amount of work (-185.2 ±6.5 kJ and -184.4 ±8.6 kJ, respectively) at the same angular velocity (21 ± 17s and 22°/s, respectively) with the same number of repetitions (8.0 and 8.0, respectively). Bland-Altman analysis showed that work (bias = 2.4%) and angular velocity (bias = 0.2%) were equalized over 9 weeks between the modes of training.

Conclusions: The procedure developed allows angular work and velocity to be standardized over 9 weeks of isotonic and isokinetic eccentric training of the knee extensors. This method could be useful in future studies in which researchers compare neuromuscular adaptations induced by each type of training mode with respect to rehabilitating patients after musculoskeletal injury.

Key Words: resistance exercise, muscle strength, knee extensors.