Abstract Background People with floppy ankle muscles paresis use ankle foot orthoses to improve their walking ability. Ankle foot orthoses also limit ankle range of motion thereby introducing ...additional problems. Insight in effects of ankle foot orthoses on body functions and activities in people with floppy paretic ankle muscles aids in clinical decision making and may improve adherence. Methods Studies published before October 27th, 2014, were searched in Pubmed, Embase, Cinahl, and Cochrane Library. Studies evaluating effects of ankle foot orthoses on body functions and/or activities in people with floppy paretic ankle muscles were included. Studies solely focusing on people with spastic paretic ankle muscles were excluded. Study quality was assessed using a custom-made scale. Body functions and activities were defined according to the International Classification of Functioning, Disability and Health. Findings Twenty-four studies were included, evaluating 394 participants. Participants were grouped according to paresis type (i) dorsiflexor paresis, (ii) plantar flexor paresis, (iii) both dorsiflexor and plantar flexor paresis. Dorsal, circular, and elastic ankle foot orthoses increased dorsiflexion during swing (by 4–6°, group i). Physical comfort with dorsal ankle foot orthoses was lower than that with circular ankle foot orthoses (groups i and iii). Dorsal ankle foot orthoses increased push-off moment (by 0.2–0.5 Nm/kg), increased walking efficiency, and decreased ankle range of motion (by 12-30°, groups ii and iii). Interpretation People with dorsiflexor paresis benefit more from circular and elastic ankle foot orthoses while people with plantar flexor paresis (and dorsiflexor paresis) benefit more from dorsal ankle foot orthoses.
Improving ankle-foot orthosis design can best be done by implementing a user-centered approach.
To provide insight into the ideas of ankle-foot orthosis users with flaccid ankle muscle paresis on the ...importance of activities and suggestions for an improved ankle-foot orthosis design.
A focus-group discussion with eight ankle-foot orthosis users (57 ± 5 years, 50% female).
Main inclusion criteria were as follows: ⩾18 years, unable to stand on tip-toe and unable to lift toes. Main exclusion criterion was spasticity of lower extremity muscles. Transcribed data were coded according to the International Classification of Functioning, Disability and Health. Thematic analysis with inductive approach was chosen to order and interpret codes.
Ankle-foot orthosis users ranked walking the most important activity followed by sitting down/standing up from a chair. Their opinion was that ankle-foot orthoses facilitate walking and standing. Ankle-foot orthosis users suggested that an improved ankle-foot orthosis design should balance between stability and flexibility.
Current ankle-foot orthoses facilitate walking which was the most important activity according to ankle-foot orthosis users. An improved ankle-foot orthosis design should enable walking and should optimize between stability and flexibility dependent on the activity and the paresis severity. Clinical relevance Experienced users of ankle-foot orthosis agreed that matching ankle-foot orthosis functions to daily-life activities is a trade-off between stability and flexibility. An improved ankle-foot orthosis design should at least enable level walking.
Individuals with chronic ankle instability (CAI) present with decreased modulation of the Hoffmann reflex (H-reflex) from a simple to a more challenging task. The neural alteration is associated with ...impaired postural control, but the relationship has not been investigated in individuals with CAI.
To determine differences in H-reflex modulation and postural control between individuals with or without CAI and to identify if they are correlated in individuals with CAI.
Descriptive laboratory study.
Laboratory.
A total of 15 volunteers with CAI (9 males, 6 females; age = 22.6 ± 5.8 years, height = 174.7 ± 8.1 cm, mass = 74.9 ± 12.8 kg) and 15 healthy sex-matched volunteers serving as controls (9 males, 6 females; age = 23.8 ± 5.8 years, height = 171.9 ± 9.9 cm, mass = 68.9 ± 15.5 kg) participated.
Maximum H-reflex (H
) and motor wave (M
) from the soleus and fibularis longus were recorded while participants lay prone and then stood in unipedal stance. We assessed postural tasks of unipedal stance with participants' eyes closed for 10 seconds using a forceplate.
We normalized H
to M
to obtain H
: M
ratios for the 2 positions. For each muscle, H-reflex modulation was quantified using the percentage change scores in H
: M
ratios calculated from prone position to unipedal stance. Center-of-pressure data were used to compute 4 time-to-boundary variables. Separate independent-samples t tests were performed to determine group differences. Pearson product moment correlation coefficients were calculated between the modulation and balance measures in the CAI group.
The CAI group presented less H-reflex modulation in the soleus (t
= -3.77, P = .001) and fibularis longus (t
= -2.59, P = .02). The mean of the time-to-boundary minima in the anteroposterior direction was lower in the CAI group (t
= -2.06, P = .048). We observed a correlation (r = 0.578, P = .049) between the fibular longus modulation and mean of time-to-boundary minima in the anteroposterior direction.
The strong relationship indicated that, as H-reflex amplitude in unipedal stance was less down modulated, unipedal postural control was more impaired. Given the deficits in H-reflex modulation and postural control in the CAI group, the relationship may provide insights into the neurophysiologic mechanism of postural instability.
Summary Objective As the muscle contracts, fibers get thicker, forcing the fascial tubular layers surrounding the muscle (endomysium, perimysium and epimysium) to expand in diameter and hence to ...shorten in length. We develop a mathematical model to determine the fraction of force generated by extremity muscles during contraction that is transmitted to the surrounding tubes of fascia. Methods Theory of elasticity is used to determine the modulus of elasticity, radial strain and the radial stress transmitted to the fascia. Results Starting with published data on dimensions of muscle and muscle force, we find radial stress is 50% of longitudinal stress in the soleus, medial gastrocnemius, and elbow flexor and extensor muscles. Conclusion Substantial stress is transmitted to fascia during muscular exercise, which has implications for exercise therapies if they are designed for fascial as well as muscular stress. This adds additional perspective to myofascial force transmission research.
Abstract The aim of the present study was to compare the effects of ankle muscle fatigue on postural control when plantarflexors (PFs) and dorsiflexors (DFs) are fatigued simultaneously compared with ...separately. This study also investigated the recovery of postural control after fatigue. Sixteen adults (eight women and eight men) performed postural trials before and after an isokinetic fatigue task involving either (i) only PFs (30° s−1 ), (ii) only DFs (120° s−1 ), or (iii) both PFs and DFs simultaneously. The fatigue task involved maximal contractions repeated until the torque produced decreased below 50% of the maximal torque. Postural trials lasted 30 s and were performed on one leg with eyes open (EO) or eyes closed (EC). Sway area, medio-lateral (ML) and antero-posterior (AP) positions and velocities were calculated from the center of pressure displacements. With EO, no effect of fatigue was found on postural variables. With EC, sway area and AP velocity increased only when both PFs and DFs were fatigued simultaneously. An effect of fatigue present only when both muscle groups are fatigued simultaneously could be due to impairment in the compensatory activity between agonist and antagonist muscles and/or a greater decrease in proprioception due to a greater number of fatigued muscles. In addition, when PFs and DFs were fatigued simultaneously, sway area and AP velocity returned to pre-fatigue values within 2 min, whereas a posterior shift in AP position persisted for 10 min. This last result may suggest a longer-lasting change in postural strategy needed for optimal postural control.
Postural control, despite its complexity, has been investigated based on single or multiple domain parameters, mainly under static conditions. The purpose of this study was to investigate whether ...semi-squatting in one leg, in contrast to simply standing in one leg, can challenge the postural control in a more dynamic manner similar to those encountered during sporting activities, using posturographic-based parameters coupled with EMG data of the ankle musculature. Our findings revealed that the decreased stability induced with single-leg semi-squatting (SLSQ) required primarily the contribution of the tibialis anterior and the peroneus brevis, as opposed to the medial gastrocnemius and lateral gastrocnemius who were the main controllers of body posture during single-leg standing (SLST) with open eyes. The lower variability found in the CoP-based parameters and the EMG activity of the muscle under investigation suggests that postural control can be more accurately assessed under dynamic conditions such as with SLSQ compared to the more static SLST test. Multi-factorial analysis of postural control combining posturographic and EMG data, particularly under dynamic conditions, can provide useful information in the diagnosis and rehabilitation of clinical cases where the assessment of muscle dysfunction is required to design a rehabilitation program and monitor patient progress.
•Simultaneous recordings of posturographic-based parameters and the EMG activity of the ankle/foot musculature suggest that postural control is challenged more during SLSQ.•Postural control with SLSQ is mainly controlled by the tibialis anterior and peroneus brevis in response to a greater anteroposterior- compared to mediolateral-directed sway of the body.•The limited body sway elicited with the traditional SLST test is mainly controlled by the gastrocnemius muscle.•Postural control may be assessed more accurately under dynamic conditions such as with SLSQ as opposed to the standard SLST test.
Display omitted Postural control assessment combining posturographic (PRG) center-of-pressure-based (CoP) parameters (total track length, ellipse area, anteroposterior and mediolateral displacement of CoP) and electromyographic (EMG) activity (percentage of maximum voluntary isometric contraction) of tibialis anterior (TA), peroneus brevis (PB), medial gastrocnemius (GM) and lateral gastrocnemius (GL) during reaching in different directions with single-leg semi-squat (SLSQ) and with the single-leg-stance (SLST) test.
Background: Sprained ankle a common orthopedic injury. The standard treatment for ankle sprains remains nonoperative. Ankle taping was used to protect and prevent ligaments excessive strain. So, the ...current study aimed at investigating the effect of spa-care Kinesio tape versus standard white athletic tape on myoelectric activities (EMG) of ankle evertors (peroneus longus) and invertors (tibialis anterior) in a chronic ankle sprain. Methods: A convenient sample of 30 patients with a chronic ankle sprain (18 females and 12 males) were included in this study. Their mean age ±SD was 24 ±1.2 years. Their height was 175±4.8 cm among men & 163±5.2 cm for females, and weight was 85±5.2 kg for males & 74±5.5 kg for women. It was a within-group design in which the same participant experienced the two types of taping compared to no taping condition. Root mean square (RMS) was measured while participants were moving the isokinetic dynamometer at an angular velocity of 120°/sec using concentric contraction mode through full ankle range of motion. The EMG (RMS) of evertors and invertors was measured immediately after the three taping ways (no tape, Kinesio tape, and athletic tape) with a one-week interval between each taping. Results: Spa-care Kinesiotape significantly reduced evertors and invertors EMG (RMS) compared with no tape or athletic tape in patients with chronic ankle sprain. Mean± SD of the evertors was 0.7 (±0.1) for no tape and 0.58 (±0.2) for Kinesio tape. The P value was 0.000 for kinesio tape in evertors compared with no tape. Also, mean± SD of the invertors was 0.87 (±0.23) for no tape, and 0.54 (±0.1) for Kinesio tape and the P value was 0.001 for Kinesio tape in invertors compared with no tape. Conclusion: Spa-care Kinesio tape may be useful for reducing EMG activity of ankle muscles in a chronic ankle sprain.
Highlights ► Fibularis longus Hoffmann reflexes decreased in more challenging body positions. ► Down-modulations of the soleus Hoffmann reflexes were consistently found. ► Fibularis longus ...down-regulated Hoffmann reflexes similarly to the soleus. ► Fibularis longus may provide synergic control over upright posture for the soleus.
To determine if the eccentric evertor/invertor and dorsiflexor/plantar-flexor ratio are altered in subjects with chronic ankle instability.
Twenty chronic ankle instability (CAI) subjects as an ...experimental group, and twenty healthy subjects as a control group, were matched in age, gender, and activity level. CAI subjects have a history of at least one ankle sprain and repeated episodes of giving way were included in CAI group. Subjects with no prior history of ankle injury were included in the control group. Ankle evertor/invertor and dorsiflexor/plantar-flexor muscles eccentric torque ratios were measured using the eccentric muscle contraction at angular velocities 60 and 120°/s.
Analysis of variance revealed that the eccentric contraction eversion/inversion ratio of CAI group was significantly lower than normal group ratio at angular velocities 60 and 120°/s (p=0.041 and 0.012) respectively. The eccentric contraction dorsiflexion/plantarflexion ratio of CAI group was significantly higher than normal group ratio at both angular velocities (p=0.036 and 0.013) respectively. Moreover, at angular velocities of 60°/s and 120°/s a deficit in inversion and eversion eccentric torques were identified in CAI group (p=0.000), plantarflexion torque deficit of CAI group (p=0.034 and 0.028), respectively, and no deficit was identified for dorsiflexion torque of CAI group (p=0.595 and 0.696) respectively.
Chronic ankle instability increases the dorsiflexion/plantarflexion muscles torque ratio and decreases the eversion/inversion ratio at angular velocities 60 and 120°/s. Therefore, the restoration of a normal eccentric inversion, eversion, and plantarflexion strength may prevent recurrent lateral ankle ligament sprain.
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