A study on postural control and lower limb muscle activation among individuals with and without ankle sprain / Nureen Shahirah Ahmad Zaghlul

Nureen Shahirah , Ahmad Zaghlul (2023) A study on postural control and lower limb muscle activation among individuals with and without ankle sprain / Nureen Shahirah Ahmad Zaghlul. Masters thesis, Universiti Malaya.

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Abstract

Damaged joint mechanoreceptors may necessitate the individuals with ankle sprain to develop coping strategies to maintain balance. This study investigated whether visual input contributes significantly to the balancing ability of individuals who had unilateral ankle sprains (AI). The specific objectives were to i) compare the time in balance (TIB) and Peroneus Longus (PL) activity with eyes-open (EO) and eyes-closed (EC) when performing balancing tasks, ii) compare the changes observed in AI with healthy individuals (HI), and iii) investigate whether the correlation between the Foot and Ankle Ability Measure (FAAM), a self-reported balance measure, with the observed performance (i.e. TIB and PL activity) is the same between AI and HI. Participants performed single leg (SL) and double leg (DL) tasks on a Lafayette stability platform. As this platform is frequently used for DL tasks, a reliability study for the SL stance on the Lafayette stability platform was first conducted with 36 healthy volunteers. After which, another 48 individuals (AI: n=24; age=23.5 ± 2.3 years; HI: n=24; age=23.5 ± 1.7 years) were recruited for the assessment. The participants performed three 20s trials of DL and SL stance in EO and EC conditions. The order of testing was randomized between conditions (i.e. EO, EC) and tasks (i.e. DL, SL). Bilateral activity of PL was recorded only during DL stance and was normalized to the peak maximum voluntary contraction (MVC). It was expressed as the side-to-side comparison, in percentage difference (%MVC). The duration the participants maintained the platform within ±1° deviation was considered as TIB. The TIB, PL activity, and FAAM scores were compared between groups and conditions. The relationship between FAAM scores and TIB and PL activity was analyzed using Spearman’s correlation coefficient (ρ). The results obtained suggest SL stance is reliable on the Lafayette stability platform. The TIB was statistically longer during EO in AI (DL_EO: 19.69 ± 0.80s; DL_EC: 18.12 ± 3.69s, p < 0.05; SL_EO: 18.59 ± 3.59s; SL_EC; 17.39 ± 2.66s, p < 0.05) and in HI (DL_EO: 19.68 ± 1.28s; DL_EC: 18.08 ± 3.60s, p< 0.05; SL_EO: 18.44 ± 2.59s; SL_EC: 17.01 ± 3.02s, p < 0.05). During DL stance, AI individuals showed a consistently lower side-to-side comparison PL activity in both EO (AI: 25.17 ± 12.53%MVC; HI: 29.82 ± 18.85%MVC, p = 0.163) and EC (AI: 24.48 ± 11.40%MVC; HI: 30.47 ± 19.03%MVC, p = 0.060) compared to HI. However, no significant difference in the TIB and side-to-side comparison PL activity was observed between groups. Additionally, a significant positive correlation was observed between FAAM and TIB during EO in AI (DL: ρ = 0.43, p = 0.04; SL: ρ = 0.59, p = 0.00), but not in HI (DL: ρ = -0.06, p = 0.77; SL: ρ = -0.11, p = 0.62). PL activity on the other hand had no significant correlation with FAAM scores in both groups irrespective of EO or EC. Overall, findings in this study suggested that AI does not rely on visual input entirely compared to HI in maintaining postural control.

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