Effect of isokinetic training on strength, functionality and proprioception in athletes with functional ankle instability

Abstract

The purpose of this study was to investigate the effects of isokinetic exercise on strength, joint position sense and functionality in recreational athletes with functional ankle instability (FAI). Strength, proprioception and balance of 24 recreational athletes with unilateral FAI were evaluated by using isokinetic muscle strength measurement, ankle joint position sense and one leg standing test. The functional ability was evaluated using five different tests. These were; single limb hopping course (SLHC), one legged and triple legged hop for distance (OLHD-TLHD), and six and cross six meter hop for time (SMHT-CSMHT). Isokinetic peak torque of the ankle invertor and evertor muscles were assessed eccentrically and concentrically at test speeds of 120 degrees /s. Isokinetic exercise protocol was carried out at an angular velocity of 120 degrees /s. The exercise session was repeated three times a week and lasted after 6 weeks. At baseline, concentric invertor strength was found to be significantly lower in the functionally unstable ankles compared to the opposite healthy ankles (p < 0.001). This difference was not present after executing the 6 weeks exercise sessions (p > 0.05). Ankle joint position sense in the injured ankles declined significantly from 2.35 +/- 1.16 to 1.33 +/- 0.62 degrees for 10 degrees of inversion angle (p < 0.001) and from 3.10 +/- 2.16 to 2.19 +/- 0.98 degrees for 20 degrees of inversion angle (p < 0.05) following the isokinetic exercise. One leg standing test score decreased significantly from 15.17 +/- 8.50 to 11.79 +/- 7.81 in the injured ankles (p < 0.001). Following the isokinetic exercise protocol, all of the worsened functional test scores in the injured ankles as compared to the opposite healthy ankles displayed a significant improvement (p < 0.01 for OLHD and CSMHT, p < 0.001 for SLHC, TLHD, and SMHT). These results substantiate the deficits of strength, proprioception, balance and functionality in recreational athletes with FAI. The isokinetic exercise program used in this study had a positive effect on these parameters.

Possible Factors Related to Functional Ankle Instability

“…This result is in agreement with past experiments demonstrating that gymnastic and strength training have a positive influence on both the sense of knee 19 and ankle 1,28 positions. Therefore, the ankle evertors weakness demonstrated by the individuals with FAI in the present study might have influenced negatively the ankle proprioception for some individuals with FAI.…”

National Athletic Trainers' Association Position Statement: Conservative Management and Prevention of Ankle Sprains in Athletes

“…55 A myriad of more advanced single-limbed hopping tasks have also been evaluated at the ankle based on time to completion, distance covered, or errors committed. Examples of these tests are the single-limb hopping course, 49,146 1-legged hop for distance, 51,146 triple-crossover hop for distance, 146 6-m hop for time, 146 cross 6-m hop for time, 50,146 6-m shuttle run, 56 single-limb hopping agility test, 145 side hop, 50,51 and figure-8 test. 50,51 One objective criterion that has been proposed to indicate readiness to RTP is 80% or better performance on the functional hopping test compared with the uninjured limb.…”

Functional Instability of the Ankle Joint: Etiopathogenesis

“…Yine Lentell tarafından yapılan 30, 90, 150, 210°/sn hızlarında yapılan çalışmada evertör kas açığı saptanamamıştır (7). İlginç olarak FAİ saptanan hasta grubunda invertör kas açığı saptanmış çalışmalar bulunmaktadır (7,17,20). Yapılan çalışmalarda belirgin eksantrik invertör kuvvet açığı saptanmıştır (5,17,20).…”

“…İlginç olarak FAİ saptanan hasta grubunda invertör kas açığı saptanmış çalışmalar bulunmaktadır (7,17,20). Yapılan çalışmalarda belirgin eksantrik invertör kuvvet açığı saptanmıştır (5,17,20). İnvertör kuvvet açığı önemli bir rolü olabileceği değerlendirilmiştir.…”

“…Selektif inhibisyon; yaralanmış bağlarda gerilme stresini artırma yeteneği olan kasları inhibe eden yaralanmış eklem tetik refleks mekanizmasının azalmış stres toleransı olarak tanımlanmıştır. Böylece ayak bileği invertörleri ilk yaralanmanın yönündeki başlangıç hareketini inhibe edebilir (2, 17,20). Ayak bileği invertör kuvveti; sabit ayak üzerinde iken lateral postural stabilitenin kaybından koruma rolü oynayabilir.…”