Study Design: Prospective randomized comparison of 2 rehabilitation programs. Objectives: The objectives of this study were to compare the effectiveness of 2 rehabilitation programs for acute hamstring strain by evaluating time needed to return to sports and reinjury rate during the first 2 weeks and the first year after return to sport. A third objective was to investigate the relationship between functional testing performance and time to return to sports and reinjury rates after return to sport. Background: Hamstring muscle strains are common in sports and often result in chronic pain, recurrent hamstring strains, and reduced sports performance. Current rehabilitation programs are primarily developed anecdotally and lack support from prospective, randomized research. Methods and Measures: Twenty-four athletes with an acute hamstring strain were randomly assigned to 1 of 2 rehabilitation groups. Eleven athletes were assigned to a protocol consisting of static stretching, isolated progressive hamstring resistance exercise, and icing (STST group). Thirteen athletes were assigned to a program consisting of progressive agility and trunk stabilization exercises and icing (PATS group). The number of days for full return to sports, injury recurrence within the first 2 weeks, injury recurrence within the first year of returning to sports, and lower-extremity functional evaluations were collected for all subjects and compared between groups. Results: The average (± SD) time required to return to sports for athletes in the STST group was 37.4 ± 27.6 days, while the average time for athletes in the PATS group was 22.2 ± 8.3 days. This difference was not statistically significant (P = .2455). In the first 2 weeks after return to sports, reinjury rate was significantly greater (P = .00343, Fisher’s exact test) in the STST group, where 6 of 11 athletes (54.5%) suffered a recurrent hamstring strain after completing the stretching and strengthening program, as compared to none of the 13 athletes (0%) in the PATS group. After 1 year of return to sports, reinjury rate was significantly greater (P = .0059, Fisher’s exact test) in the STST group. Seven of 10 athletes (70%) who completed the hamstring stretching and strengthening program, as compared to only 1 of the 13 athletes (7.7%) who completed the progressive agility and trunk stabilization program, suffered a recurrent hamstring strain during that 1-year period. Conclusions: A rehabilitation program consisting of progressive agility and trunk stabilization exercises is more effective than a program emphasizing isolated hamstring stretching and strengthening in promoting return to sports and preventing injury recurrence in athletes suffering an acute hamstring strain. Future randomized clinical trials should investigate the potential for progressive agility and trunk stabilization programs in the prevention of hamstring strain injury during sports.

J Orthop Sports Phys Ther. 2004;34(3):116-125.

Key Words: agility, injury recurrence, muscle injury, physical therapy, stretching

Study Design: Repeated-measures counterbalanced design. Objectives: To determine the effect of rate of force application on anterior tibial displacement and anterior tibial stiffness when measured with the KT-2000 knee arthrometer. Background: Clinicians and researchers frequently use the KT-2000 to quantify anterior tibial displacement and stiffness. While many factors (ie, tibial rotation, alignment of the arthrometer, etc) have been identified to affect KT-2000 measurements, the effect of the rate of force application has not been studied. Methods and Measures: Seventeen recreationally active males between the ages of 19 and 36 years (mean age ± SD, 27.8 ± 5.3 years) with no previous history of knee injury participated. With the knee in 25° of flexion, the KT-2000 was applied to the participants’ anterior tibia. While the distal femur was stabilized, the first author applied a posterior-to-anterior force at a fast and slow rate. Three trials for the slow and fast rates of force application were averaged and used for statistical analysis. Anterior tibial displacement (mm) was measured at 133 N and the related anterior tibial stiffness (N/mm) values were calculated between 89 and 133 N. Separate paired t tests with Bonferroni adjustment were used to determine if differences in displacement and stiffness between rates of force application were present. Results: Stiffness was significantly greater in the slow (mean ± SD, 58 ± 22 N/mm) as compared to the fast trials (mean ± SD, 47 ± 19 N/mm) (P = .005). Differences in displacement, however, were small and not significant (P = .132) between the slow (mean ± SD, 3.9 ± 1.5 mm) and fast (mean ± SD, 4.0 ± 1.6 mm) trials. Conclusion: The rate of force application affects anterior tibial stiffness but not anterior tibial displacement when measured with the KT-2000. This suggests that to ensure reliable results when using the KT-2000, the rate of force application must be controlled when measuring stiffness between 89 and 133 N, but not when measuring anterior tibial displacement at 133 N.

J Orthop Sports Phys Ther. 2004;34(3):132-139.

Key Words: ACL, anterior cruciate ligament, KT-2000, viscoelasticity