Ankle motion at the talocrural joint is important for normal gait. Dorsiflexion, both active and passive, occurs during stance and swing phase, respectively. It has been found that about 10° of passive dorsiflexion is required during stance phase. During swing phase, the muscles of the anterior compartment of the leg must be of sufficient strength to produce active dorsiflexion to near neutral (foot at 90°). Moderate lack of passive dorsiflexion results in early heel-off during stance phase. More extreme dorsiflexion limitations may result in overpronation at the subtalar joint. The purpose of this study was to determine an efficient intervention to increase active ankle dorsiflexion range of motion (ROM).
Three groups of 9 healthy college students (27 in total, 54 ankles) were recruited for the study. Each volunteer signed an informed consent form. The patients were randomly assigned to 3 groups. The stretch group stretched the triceps surae using a rocker designed stretching system, the strength group strengthened isotonically the muscles in the anterior compartment of the leg, and a control group received no intervention.
Patients in the strength group used a 10-lb ankle weight strapped to their forefoot and performed 30 repetitions each day, 5 days each week, for both lower extremities, for 6 weeks. The stretch group stretched for 30 seconds, 3 repetitions each day, 5 days each week, for 6 weeks. The control group maintained its prestudy activity level. Active ankle dorsiflexion ROM was measured prior to intervention and at 3 and 6 weeks. The same examiner who was blinded to group assignment did all measurements of active ankle dorsiflexion.
A 1-way analysis of variance for repeated measures was done to determine whether a significant difference existed between groups. A post-hoc Tukey's Honestly Significant Difference test was performed to determine which ROM measurements were significantly different. Significance level was P < .05.
It was found for the strength group that the baseline active ankle dorsiflexion ROM measurement 4.2° was significantly different from the ROM measurement at 3 weeks, 6.6°, and 6 weeks, 7.1°. The stretch group baseline dorsiflexion ROM measurement 1.6° was not significantly different at 3 weeks (3.1°) but was significantly different at 6 weeks (4.2°). No significant differences were observed for the control group.
Active ankle dorsiflexion ROM was increased more quickly for the strength group than for the stretch group. The stretch group took 6 weeks to gain enough dorsiflexion to be significantly different from the baseline dorsiflexion ROM. Clinically, it may be appropriate for patients lacking ankle dorsiflexion to strengthen the muscles in the anterior compartment of the leg along with a stretching program for the triceps surae muscles.