Treatment of exercise-induced muscle injury via hyperbaric oxygen therapy

Purpose: This study examined the role of hyperbaric oxygen therapy (HBO) in the treatment of exercise-induced muscle injury. Methods: 21 college-aged male volunteers were assigned to three groups: control, immediate HBO (iHBO ), and delayed HBO (dHBO). All subjects performed 6 sets (10 repetitions pe r set) of eccentric repetitions with a load equivalent to 120% of their con centric maximum. HBO treatments consisted of 100-min exposure to 2.5 ATA an d 100% oxygen with intermittent breathing of ambient air (30 min at 100% O- 2, 5 min at 20.93% O-2). HBO treatments began either 2 (iHBO) or 24 h (dHBO ) postexercise and were administered daily through day 4 postexercise. Fore arm flexor cross-sectional area (CSA) and T2 relaxation time via magnetic r esonance imaging (MRI) were assessed at baseline, 2, 7, and 15 d postinjury . Isometric strength and rating of perceived soreness of the forearm flexor s were assessed at baseline, 1, 2, 3, 4, 7, and 15 d postinjury. Serum crea tine kinase (CK) was assessed on day 0 and on days 1, 2, 7, and 15 postinju ry. Results: Mean baseline CSA values were: 2016.3, 1888.5, and 1972.2 mm(2 ) for control, iHBO, and dHBO, respectively. All groups showed significant increases in CSA in response to injury (21% at 2 d, 18% at 7 d) (P < 0.0001 ), but there were no significant differences between groups (P = 0.438). Me an baseline T2 relaxation times were: 26.18, 26.28, and 27.43 msec for cont rol, iHBO, and dHBO, respectively. Significant increases in T2 relaxation t ime were observed for all groups (64% at 2 d, 66% at 7 d, and 28% at 15 d) (P < 0.0001), but there were no significant differences between groups (P = 0.692). Isometric strength (P < 0.0001), serum CK levels (P = 0.0007), and rating of perceived soreness (P < 0.0001) also indicated significant muscl e injury for all groups, but there were no differences between groups (P = 0.459, P = 0.943, and P = 0.448, respectively). Conclusion: These results s uggest that hyperbaric oxygen therapy was not effective in the treatment of exercise-induced muscle injury as indicated by the markers evaluated.