Echocardiographic evaluation of stress test for determining safety of participation in strength training

Suitability for safe participation in aerobic exercise is typically determined by a cardiopulmonary exercise test, using a treadmill or cycle. With increased participation in strength training by healthy clients as well as rehabilitation patients, there is a need to develop a test for determining suitability for safe participation in strength training. This investigation describes a strength stress test that may be used for determining safety of participation in strength training. Ten healthy subjects (28.3 +/- 5.9 years and 75.3 +/- 14.4 kg) with strength training experience participated. Following a resting echocardiogram, subjects performed 3 sets of leg presses at an 8 repetition maximum. Resting and exercise end-diastolic and end-systolic volumes were obtained during the last repetition of each set and were indexed for body surface area (ESV(I), EDV(I)). Ejection fraction, cardiac output, and stroke volume were calculated. Cardiac output increased significantly (p < 0.05) for each set in comparison to rest and also during the third set in comparison to sets 1 and 2. Ejection fraction increased, whereas ESV(I) and EDV(I) decreased significantly for each set compared to rest, and also during sets 2 and 3 when compared to set 1. Responses to sets 2 and 3 indicate increased cardiac stress with increasing sets to exhaustion analogous to changes observed during tests designed to assess anaerobic and aerobic power. Thus, this protocol may be used as a test for evaluating the ability to participate in modest strength training consistent with exercise prescriptions developed for participants of health clubs and rehabilitation facilities. Strength testing protocol described may be adapted and modified for evaluating other lifts such as arm work and job-related tasks.