Chronic stretching and running economy

Research demonstrates an inverse relationship between the range of motion o f selected joint movements (flexibility) and running economy. Since stretch ing exercises have been shown to increase joint range of motion, stretching exercises may be contraindicated for endurance running performance. Hence, this study investigated the influence of a 10-week program of stretching e xercises on the oxygen costs of a 10 min sub-maximal (approx. 70% peak VO2) treadmill run. Thirty-two (16 female, 16 male) physically active, treadmil l accommodated, college students participated in the study. All participant s maintained their current activity level, with half the participants (8 fe male, 8 male) adding a 40 min, 3 days per week session of thigh and calf mu scle stretching exercises. After 10 weeks, the stretching group (STR) exhib ited a significant (P<0.05) increase (3.1+/-2.2 cm) in the sit-and-reach, w hile the non-stretching group (CON) experienced no significant (P>0.05) cha nge (0.0+/-0.4 cm). However, neither the STR nor the CON exhibited a signif icant (P>0.05) change in the O-2 cost for the submaximal run. It is conclud ed, therefore, that a chronic stretching program does not necessarily negat ively influence running economy.