Rationale:

Hatha yoga has been practiced for thousands of years and has become a popular form of exercise. Previous studies have focused on changes in ventilatory function and stress reduction consequent to yoga training. However, studies investigating the effects of yoga on muscular strength and endurance, flexibility, balance, and aerobic capacity are lacking.

Objective:

This study was designed to investigate changes in VO₂max, ventilation, maximal heart rate, muscular strength and endurance, flexibility, and balance after 8 weeks of thrice-weekly (50 min per session) yoga training.

Methodology:

Healthy volunteers (age 20-55)(n = 34) were randomly divided into an experimental group (yoga) and a control group (no exercise). Both groups were tested before and after the 8-week training period. The tests assessed VO₂max, maximal heart rate, FVC, FEV₁, muscular strength and endurance, flexibility, and balance.

Results:

The experimental group had significant (P <.05) improvements in trunk flexion (7[degrees]), trunk extension (8[degrees]), trunk rotation to the right (22[degrees]) and left (19[degrees]), ankle range of motion (6[degrees]), sit and reach (3 in), back scratch on the right (1.2 in) and left (1.2 in), shoulder elevation (1.6 in), trunk lift (1.9 in), push-ups (6), curl-ups (14), and one-leg stand (17 sec) compared to the control group. There were no significant improvements in maximal heart rate, VO₂max, FVC, FEV₁, or functional reach as a result of training.

Conclusion:

When practiced regularly, Hatha yoga can significantly improve muscular strength and endurance, flexibility, and balance. However, the metabolic intensity of Hatha yoga does not appear to be sufficient to improve cardiorespiratory measures.