Biomechanical and viscoelastic properties of the ankle muscles in men with previous history of ankle sprain

Influence of pain, sequential movement or short-term rest performance on the evaluation results of neck muscle mechanical properties: a case-control study

INTRODUCTION

Individuals with neck pain (NP) often experience altered muscle mechanical properties (MMPs), such as increased tone and stiffness. Myotonometry has become a reliable, noninvasive tool for measuring MMPs. However, the effect of movement and rest on MMPs in acute neck pain (ANP) individuals remains insufficiently explored.

OBJECTIVE

This study aimed to evaluate how sequential movement and short-term rest influence the MMPs of neck muscles in subjects with ANP.

METHODS

A case-control study was conducted with 37 subjects with APN and 37 matched healthy controls. Muscle mechanical properties were assessed by myotonometry at baseline, post-movement (after a motion assessment sequence), and post-rest. The outcome measures of MMPs were frequency or tone, stiffness, decrement, which is the inverse of elasticity, relaxation, and creep.

RESULTS

Subjects with ANP showed higher muscle tone, stiffness and decrement, and lower relaxation than controls, all with p < .05. In the ANP group, decrement was the only property that showed a significant change after movement and rest, both with p < .05. Reduced means values (m) with its standard deviation (SD) were observed post-movement (m = 1.35 Ø, SD = 0.03) and post-rest (m = 1.33 Ø, SD = 0.03) compared to baseline values (m = 1.43 Ø, SD = 0.04). The other MMPs remained stable across evaluation times (p > .05).

CONCLUSION

The evaluation of MMPs should be conducted prior to any mobility protocol to ensure that the results reflect the basal tissue characteristics in individuals with ANP, highlighting decrement as a sensitive marker of these changes.

Myotonometric assessment of peroneus longus muscle mechanical properties during contraction in athletes with and without chronic ankle instability

Our recent findings in athletes with chronic ankle instability (CAI) revealed increased tone and stiffness alongside reduced elasticity in the peroneus longus (PL) during myotonometric (MYO) measurements at rest, suggesting diagnostic relevance. MYO recordings during muscle contraction in healthy subjects showed an active muscle stiffness influence on MYO parameters, suggesting its potential impact on CAI-related MYO findings. However, it remains unknown whether PL stiffening observed recently in CAI athletes at rest can also be detected while PL muscle contraction. This study, using myotonometry, examines the PL mechanical properties during a motor task mimicking PL's biomechanical function, i.e., simultaneous isometric foot pronation and plantar flexion (IFPPF) at 30 % and 100 % of maximal voluntary contraction (MVC) in athletes with CAI. Nineteen adult male athletes with CAI (per International Ankle Consortium criteria) and 19 control (CO) athletes without lateral ankle sprain incidents comprised the study groups. Both groups had similar anthropometric parameters and training volume. Simultaneous force and MYO measurements were performed at 30 % and 100 % of MVC-IFPPF, using a MyotonPRO® device. Five MYO parameters were recorded in the PL: frequency, stiffness, decrement, relaxation time, and creep. No significant inter-group differences were observed in MYO parameters and force values measured during the 30 % and 100 % of MVC-IFPPF. This study, employing myotonometry, is the first to demonstrate the lack of significant differences between CAI and CO athletes in the MYO parameters measured in the PL muscle at submaximal and maximal contraction during simultaneous IFPPF, contrasting with our previous MYO results in CAI at rest.

Minimum effective plyometric training volume in sedentary individuals: Impact on lower limb viscoelastic properties and functional performance in a randomised controlled trial

Sedentary lifestyles reduce muscle mass, strength, power, and alter viscoelastic properties. Plyometric jump training (PJT) shows promise in countering these effects, but the optimal training volume for individuals with low athletic performance remains unclear. This study aimed to determine the minimal PJT volume required to improve muscle and tendon viscoelastic properties, strength, and power in sedentary individuals. A double-blind randomised controlled trial included 44 participants divided into three groups: Control Group (CG) (n = 16), Reduced Volume Training Group (RVTG) (n = 16), and Training Group (TG) (n = 12). The four-week PJT programme involved three weekly sessions with gradual volume increments; RVTG performed 50% less volume than TG. Baseline and follow-up assessments included the isokinetic standing up (SU) and sitting down (SD) phases at 15 cm/s and 5 cm/s, and myotonometer measurements. In the SU phase at 15 cm/s, significant differences were found (p = 0.01) with higher values in TG (10.0 ± 3.3 N/kg) compared to CG and RVTG. At 5 cm/s, differences in SD were observed (p = 0.002). For Achilles tendon properties in RVTG: stiffness (p = 0.04), decrement (p = 0.01), and relaxation (p = 0.02). A PJT volume of 2,414 jumps improved muscle strength, while 1,207 jumps altered tendon properties.

Individuals with chronic ankle instability show altered regional activation of the peroneus longus muscle during ankle eversion

Individuals with chronic ankle instability (CAI) present muscular weakness and potential changes in the activation of the peroneus longus muscle, which likely explains the high recurrence of ankle sprains in this population. However, there is conflicting evidence regarding the role of the peroneus longus activity in CAI, possibly due to the limited spatial resolution of the surface electromyography (sEMG) methods (i.e., bipolar sEMG). Recent studies employing high-density sEMG (HD-sEMG) have shown that the peroneus longus presents differences in regional activation, however, it is unknown whether this regional activation is maintained under pathological conditions such as CAI. This study aimed to compare the myoelectric activity, using HD-sEMG, of each peroneus longus compartment (anterior and posterior) between individuals with and without CAI. Eighteen healthy individuals (No-CAI group) and 18 individuals with CAI were recruited. In both groups, the center of mass (COM) and the sEMG amplitude at each compartment were recorded during ankle eversion at different force levels. For the posterior compartment, the sEMG amplitude of CAI group was significantly lower than the No-CAI group (mean difference = 5.6% RMS; 95% CI = 3.4-7.6; p = 0.0001). In addition, it was observed a significant main effect for group (F1,32  = 9.608; p = 0.0040) with an anterior displacement of COM for the CAI group. These findings suggest that CAI alters the regional distribution of muscle activity of the peroneus longus during ankle eversion. In practice, altered regional activation may impact strengthening programs, prevention, and rehabilitation of CAI.

Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.

Effect of kinesio taping intervention on the muscle strength and balance of college basketball players with functional ankle instability

Objective: The aim of this study was to investigate the effects of acute Kinesio Taping (KT) intervention on the muscle strength and balance ability of college basketball players with functional ankle instability (FAI).

Methods: Thirty college basketball players with FAI were treated with acute KT to test the changes in their muscle strength and balance ability.

Results: After acute KT intervention, the ankle dorsiflexion moment and the ankle plantar flexion moment increased by 34% and 19.9%, respectively. The stable plane test with the subjects’ eyes open decreased by 1%, whereas that with the subjects’ eyes closed decreased by 1.1%. The swaying environment test with the subjects’ eyes open increased by 2.4%. The swaying plane test with the subjects’ eyes open increased by 5.1%, whereas that with the subjects’ eyes closed increased by 16.2%. The swaying environment test with the subjects’ eyes open plus the use of a plane increased by 12.1%.

Conclusion: KT can increase the isokinetic strength of the ankle dorsum muscle and plantar flexion of college basketball players with FAI. The effect of KT in the static balance test was weaker than that in the dynamic balance test. The findings indicate that KT can significantly improve the balance ability of college basketball players with FAI during dynamic sports.