Altered Movement Biomechanics in Chronic Ankle Instability, Coper, and Control Groups: Energy Absorption and Distribution Implications

Abstract

Context: Patients with chronic ankle instability (CAI) exhibit deficits in neuromuscular control, resulting in altered movement strategies. However, no researchers have examined neuromuscular adaptations to dynamic movement strategies during multiplanar landing and cutting among patients with CAI, individuals who are ankle-sprain copers, and control participants.

Objective: To investigate lower extremity joint power, stiffness, and ground reaction force (GRF) during a jump-landing and cutting task among CAI, coper, and control groups.

Design: Cross-sectional study.

Setting: Laboratory.

Patients or other participants: A total of 22 patients with CAI (age = 22.7 ± 2.0 years, height = 174.6 ± 10.4 cm, mass = 73.4 ± 12.1 kg), 22 ankle-sprain copers (age = 22.1 ± 2.1 years, height = 173.8 ± 8.2 cm, mass = 72.6 ± 12.3 kg), and 22 healthy control participants (age = 22.5 ± 3.3 years, height = 172.4 ± 13.3 cm, mass = 72.6 ± 18.7 kg).

Intervention(s): Participants performed 5 successful trials of a jump-landing and cutting task.

Main outcome measure(s): Using motion-capture cameras and a force plate, we collected lower extremity ankle-, knee-, and hip-joint power and stiffness and GRFs during the jump-landing and cutting task. Functional analyses of variance were used to evaluate between-groups differences in these dependent variables throughout the contact phase of the task.

Results: Compared with the coper and control groups, the CAI group displayed (1) up to 7% of body weight more posterior and 52% of body weight more vertical GRF during initial landing followed by decreased GRF during the remaining stance and 22% of body weight less medial GRF across most of stance; (2) 8.8 W/kg less eccentric and 3.2 W/kg less concentric ankle power, 6.4 W/kg more eccentric knee and 4.8 W/kg more eccentric hip power during initial landing, and 5.0 W/kg less eccentric knee and 3.9 W/kg less eccentric hip power; and (3) less ankle- and knee-joint stiffness during the landing phase. Concentric power patterns were similar to eccentric power patterns.

Conclusions: The CAI group demonstrated altered neuromechanics, redistributing energy absorption from the distal (ankle) to the proximal (knee and hip) joints, which coincided with decreased ankle and knee stiffness during landing. Our data suggested that although the coper and control groups showed similar landing and cutting strategies, the CAI group used altered strategies to modulate impact forces during the task.

Keywords: ankle sprains; energetics; ground reaction forces; kinetics; landing mechanics.

Figure 1

Three-dimensional ground reaction force patterns across the entire stance phase during the jump-landing and cutting task. Medial ground reaction force: A, of the chronic ankle instability (CAI), coper, and control groups during stance phase; B, between the CAI and coper groups; C, between the CAI and control groups; D, between the coper and control groups. Posterior ground reaction force: E, of the CAI, coper, and control groups during stance phase; F, between the CAI and coper groups; G, between the CAI and control groups; H, between the coper and control groups. Continued on next page.

Figure 1

Continued from previous page. Vertical ground reaction force: I, of the CAI, coper, and control groups during stance phase; J, between the CAI and coper groups; K, between the CAI and control groups; L, between the coper and control groups. B–D, F–H, and J–L, mean differences (bold solid curve) and corresponding 95% confidence intervals (shaded area). When the shaded area does not overlap with the zero line (horizontal line), a difference is indicated between groups (P < .05). ^a Peak dorsiflexion angle (50% of stance). ^b Knee-flexion angle (50% of stance). ^c Hip-flexion angle (32% of stance).

Figure 2

Lower extremity energy patterns across the entire stance phase during the jump-landing and cutting task. Ankle-joint power: A, of the chronic ankle instability (CAI), coper, and control groups during the stance phase; B, between the CAI and coper groups; C, between the CAI and control groups; D, between the coper and control groups. Knee-joint power: E, of the CAI, coper, and control groups during stance phase; F, between the CAI and coper groups; G, between the CAI and control groups; H, between the coper and control groups. Continued on next page.

Figure 2

Continued from previous page. Hip-joint power: I, of the CAI, coper, and control groups during stance phase; J, between the CAI and coper groups; K, between the CAI and control groups; and, L, between the coper and control groups. B–D, F–H, and J–L, mean differences (bold solid curve) and corresponding 95% confidence intervals (shaded area). When the shaded area does not overlap with the zero line (horizontal line), a difference is indicated between groups (P < .05). ^a Peak dorsiflexion angle (50% of stance). ^b Knee-flexion angle (50% of stance). ^c Hip-flexion angle (32% of stance).