Flexibility and posture assessment in relation to hamstring injury.
Posture and flexibility were assessed in 34 athletes. Subjects were divided into two groups: (1) a noninjured group that did not have a history of hamstring strain injury within the previous 12 months; (2) an injured group that had a history of hamstring strain within the previous 12 months. Ten postural components were assessed: head erectness; shoulder symmetry; spinal curvature; hip symmetry; foot and ankle alignment; knee hyperextension; upper back roundness; trunk erectness; abdomen protrusion; and lumbar lordosis. Hamstring flexibility was assessed in both legs. Results indicated no difference (P > 0.05) in flexibility between groups (mean(s.d.) of both legs was: noninjured = 77.1(9.3) degrees, injured = 77.8(9.2) degrees. Also no difference (P > 0.05) was observed between the injured limb and the noninjured limb for injured subjects (injured limb = 78.1(11.1) degrees, noninjured limb = 77.5(8.1) degrees. A significant difference (P < 0.01) between groups occurred in low back posture (lumbar lordosis). No other difference occurred in the remaining nine posture components between groups. Intercorrelation coefficients among posture components indicated that at best only 53% of common variance existed between any two components (head and shoulder components: r = 0.73, P < 0.01). All other correlations indicated less than 40% common variance between components. The results of the study indicate that while differences in hamstring flexibility are not evident between injured and noninjured groups poorer low back posture was found in the injured group. Regular monitoring of posture in athletes is recommended.