Relationship between cardiopulmonary responses and isokinetic moments: the optimal angular velocity for muscular endurance

Most protocols for testing and rehabilitation for recovery and improvement of muscular endurance have been set at 180°/sec, 240°/sec, and 300°/sec. These protocols can cause confusion to clinical providers or other researchers. This study was aimed at investigating the optimal isokinetic angular speed for measuring or developing muscular endurance after assessing the relationship between cardiopulmonary responses and isokinetic moments. This study was conducted with 31 male and female college students. Graded exercise test and body composition were measured as well as the isokinetic moments of the knee muscles at three angular speeds: 180°/sec, 240°/sec, and 300°/sec. The specific isokinetic moments of knee muscles that were measured included: peak torque (PT) and total work (TW) on extensor (e) and flexor (f) of knee joints, which were denoted as ePT180, fPT180, eTW180, fTW180, ePT240, fPT240, eTW240, fTW240, ePT300, fPT300, eTW300, and fTW300 according to the three angular speeds. Spearman correlation test was used to examine the relationship between the sum means of cardiopulmonary responses and the variables of isokinetic moments. This study confirmed that the optimal angular speed for testing or training for muscular endurance was 180°/sec, which showed a stronger relationship between cardiopulmonary responses and isokinetic moments. Therefore, this angular speed is recommended for testing and training for muscular endurance of the knee joints.