This randomized clinical study aims to evaluate the effectiveness of myofascial release and eccentric training coupled with a stabilizing taping, in improving range of motion, strength, pain and ankle stability in footballers with recurrent ankle sprains. Although changes were reported in both study groups, we found no differences between the two interventions in improving the dependent variables studied. Ankle sprains represent in soccer practice one of the injuries leading to the greatest loss of training time. To reduce the risk of injury in an unstable ankle, as a result of restricted range of motion or poor stability, balance should be improved [17], attempting to reduce perceived pain by increasing strength [18].
Range of movement
Regardless of the administration of a stabilizing taping techniques, the combination of myofascial release and strength training achieved proper transmission of proprioceptive information. A significant increase in such transmission ability was noted in plantar flexion and dorsiflexion movements after the intervention and at follow-up. Our results are in line with those reported by Greig and McNaughton [8], who implemented an exercise protocol that replicated the activity profile of match play in 10 healthy footballers, observing improvement of active joint mobility, reducing in turn the risk of injury.
Our study has shown the effectiveness of myofascial release combined with muscle strength training in improving ankle range of motion. These changes may be due to facilitated sliding of the fascial plane, normalizing the mechanoreceptor activation threshold in the fascial tissue and to recruitment. The results obtained in the two groups included in this study are similar to those reported by Brandolini et al. [35] on the efficacy of myofascial release in improving ankle range of motion.
Stability
Fatigue affects balance in soccer players [8], so poor stability promotes the feeling of instability. The ankle retinaculum is a structure rich in proprioceptive receptors [26], whose damage can trigger undue proprioceptor activation, causing inaccurate proprioceptive afferent stimulus.
Our study noted improvements in the average speed in antero-posterior and mid-lateral movements, with visual support, and in the percentage of load distribution between left and right legs, in athletes treated with manual therapy and eccentric strength exercises. Similarly, those players who also used kinesiotaping exhibited changes in the mid-lateral pressure center with and without visual support. Although there was no specific proprioceptive exercise intervention, improvements in stability are similar to those found after implementing various approaches to balance training [17].
Kim and Cha [36] reported how the use of stretch bands increases the stability of the ankle allowing mobility within the elastic range, improving gait. A number of studies [37, 38] have reported the effect of adhesive taping on the ankle for improving dynamic balance and stability in young footballers with chronic ankle instability. Although Refshauge et al. [39] observed that the protective effect of taping did not improve proprioception in the plantar flexion and dorsiflexion plane, other authors [20] have reported an increase in the ability of stable gait after applying kinesiotaping in soccer players with lateral ankle sprains. However, although ankle stability improved in our study, we found no significant differences when comparing the stability assessment between footballers who used kinesiotaping (experimental group) and those who only performed the myofascial release and strength training intervention. Accordingly, our findings are consistent with those described by Stecco et al. [40] who reported improved stability after administration of a fascial therapy intervention on the ankle retinaculum
Ankle muscle strength
The ability of the muscular system to generate strength is based on the combination of the neural impulse of the central nervous system and the peripheral contractile function. Changes in functional performance that occur after strenuous exercise are associated with changes in the central or peripheral systems [41]. Type II muscle fibers are more prone to muscle damage induced by exercise, suffering a high degree of remodeling that may temporarily affect the performance of explosive movements [42]. The symptoms of muscle damage are significantly reduced in trained athletes as a result of an adaptation known as the repeated bout effect [43]. This adaptation depends on the specific muscle group that is being used [44].
A protocol based on high-intensity squats, such as the one used in our study combined with an isoinertial device, causes a 48-hour drop in performance after exercise, although the isometric strength rapidly recovers. The drop in maximum strength caused by a maximum voluntary isometric contraction is used as a marker of exercise-induced muscle damage despite inter- and intra-subject variability in the response to exercise-induced muscle damage [45].
Fiber-specific remodeling, coupled with reduced neuronal impulse, promotes slower performance recovery, thereby improving the ability to exert force quickly [46]. The use of an isoinertial device together with the administration of myofascial release in our study has shown its effectiveness in improving ankle strength in dorsiflexion and plantar flexion movements. This improvement of eccentric muscle strength can have an impact on the training model and its functional asymmetries, with the aim of preventing injuries such as ankle sprains [9, 15].
Perceived pain
Poor coordination in the development of ankle movement can cause periarticular inflammation, in turn activating periarticular nociceptive receptors. The long-term effects of trauma to the lower limbs not only appear on the affected side and may cause alterations on the contralateral side.
The ankle retinaculum and deep fascia are highly innervated connective tissue structures that facilitate force transmission, motor coordination, and proprioception [40]. Improvements in perceived pain observed in both groups separately and the repeated-measures analysis have been previously reported in studies applying manual therapy to the fascial tissue [35]. In the same way, a protocol of exercises using stretch bands, weights, plyometric and proprioceptive exercises in people with chronic ankle instability has shown improvements in range of motion in ankle plantar flexion and dorsiflexion, reducing pain [18]. The decrease in pain under load-bearing conditions observed in our study allowed the footballers to increase their athletic performance.
Limitations
The main study limitation is the reduced sample size, a drawback we have attempted to minimize by performing an intent-to-treat analysis. Similarly, the use of more objective measuring instruments would have offered a more comprehensive analysis of the variables studied.