Leg Muscle Activity Research Articles

Nordic walking must be a common fitness technique and one of the effective rehabilitation menu for many gait disorders on oxygen intake and muscle activity

Nordic walking (NW) has spread recently not only in European countries but in Japan as well. Although the use of NW has begun in several clinical settings, opinions remain divided on exercise load and muscle activity of the legs during walking. So subjects’ oxygen intake and leg muscle activity during NW were measured and compared with normal walking. The subjects were 14 healthy adult men (21.3 years old). Normal walking and NW were performed with a uniform walking cadence of 110 steps per minute. Subjects walked 10 m in each movement task, and oxygen intake, carbon dioxide emission and muscle activity were measured. Activities in the rectus femoris, adductor magnus, tensor fasciae latae, biceps femoris, tibialis anterior, and lateral head of the gastrocnemius muscles were measured. The obtained electromyogram waveforms were processed with a 20-500 Hz bandpass filter, after which the integrated value from full-wave rectification was obtained. The integrated value from full-wave rectification for each muscle during walking was normalized with 100% maximum voluntary contraction (%MVC). In the measurement of the exercise load, oxygen intake and carbon dioxide emission were measured for 10 minutes and compared every minute though the paired t -test ( P < 0.05). %MVC tended to increase in the rectus femoris and adductor magnus muscles during NW compared with normal walking. In contrast, %MVC tended to decrease in the tensor fasciae latae, tibialis anterior, and lateral head of the gastrocnemius muscles during NW compared with normal walking. Oxygen intake of NW were higher than normal walking after 5 minutes from the beginning of walking exercise. We discovered that NW needs more oxygen and muscle activity than Normal walking. NW must become one of the effective total exercise menu for many elderly person with knee pain and hip pain. This study was supported by JSPS KAKENHI Grant Number JP16K16473.

Lower limb muscle kinetics during Y-balance test between children with and without developmental coordination disorder

Despite the atypical muscle activation patterns exhibited in children with developmental coordination disorder (DCD) during static postural control tasks, no studies to date have investigated if this pattern is shown in dynamic postural control conditions. This study aimed to evaluate the leg muscle patterns during the lower quarter Y-balance test (YBT-LQ) between children with and without DCD. Forty-eight children with DCD (mean age ± SD = 8.03 ± 1.10 years; 37 males and 11 females) and fifty-one children with typical development (mean age ± SD = 7.82 ± 1.06 years; 32 males and 19 females) were allocated to the DCD group and control group, respectively, after screening by two physiotherapists. Rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis muscle activations (of the weight-bearing leg) were measured by surface electromyography and foot contact switches during the YBT-LQ anterior, posteromedial and posterolateral reaches. Children with DCD revealed a lower YBT-LQ score (P < 0.001) when compared to the control group for all reach directions. Moreover, the posteromedial and anterior reach directions revealed different muscle activation patterns with a lower gastrocnemius medialis peak activation (P = 0.029) and a shorter gastrocnemius medialis muscle time-to-peak duration (P < 0.05), respectively, in children with DCD compared with the controls. Children with DCD exhibited a less competent YBT-LQ performance and dissimilar leg muscle activation patterns in dynamic balance situations. They may adopt a different lower limb neuromuscular control than typically developing children to compensate for the balance deficits. Rehabilitation interventions for children with DCD should therefore incorporate dynamic postural control elements with an emphasis on phasic neuromuscular control of the weight-bearing leg.

O 089 - A soft robotic exosuit assisting the paretic ankle in patients post-stroke: Effect on muscle activation during overground walking

This study compared overground walking with and without exosuit assistance in post-stroke patients. Exosuit-assisted walking was found to improve paretic propulsion and ground clearance during swing, two common gait deviations in stroke patients. No changes in leg muscle activity was found, motivating further study of the exosuit as a tool for gait training during stroke rehabilitation.

Energy cost and lower leg muscle activities during erect bipedal locomotion under hyperoxia

BackgroundEnergy cost of transport per unit distance (CoT) against speed shows U-shaped fashion in walking and linear fashion in running, indicating that there exists a specific walking speed minimizing the CoT, being defined as economical speed (ES). Another specific gait speed is the intersection speed between both fashions, being called energetically optimal transition speed (EOTS). We measured the ES, EOTS, and muscle activities during walking and running at the EOTS under hyperoxia (40% fraction of inspired oxygen) on the level and uphill gradients (+ 5%).MethodsOxygen consumption left(dot{V}{mathrm{O}}_2right) and carbon dioxide output left(dot{V}{mathrm{CO}}_2right) were measured to calculate the CoT values at eight walking speeds (2.4–7.3 km h−1) and four running speeds (7.3–9.4 km h− 1) in 17 young males. Electromyography was recorded from gastrocnemius medialis, gastrocnemius lateralis (GL), and tibialis anterior (TA) to evaluate muscle activities. Mean power frequency (MPF) was obtained to compare motor unit recruitment patterns between walking and running.Results dot{V}{mathrm{O}}_2 , dot{V}{mathrm{CO}}_2 , and CoT values were lower under hyperoxia than normoxia at faster walking speeds and any running speeds. A faster ES on the uphill gradient and slower EOTS on both gradients were observed under hyperoxia than normoxia. GL and TA activities became lower when switching from walking to running at the EOTS under both FiO2 conditions on both gradients, so did the MPF in the TA.ConclusionsES and EOTS were influenced by reduced metabolic demands induced by hyperoxia. GL and TA activities in association with a lower shift of motor unit recruitment patterns in the TA would be related to the gait selection when walking or running at the EOTS.Trial registrationUMIN000017690 (R000020501). Registered May 26, 2015, before the first trial.

Leg and back muscle activity, heart rate, performance and comfort during sitting, standing, and using a sit-stand-support with different seat angles

Long-lasting sitting and standing is related to several health risks and alternatives to these positions are needed. This study compared muscle activity, heart rate, performance, and comfort between sitting, standing, and using a stable sit-stand-support with four different seat angles. Twenty-one subjects fulfilled three tasks (typing, a tweezing task and a task simulating ironing) in every position for five minutes. The heart rate was higher using a sit-stand-support and standing compared to sitting. The activity of the m. erector spinae was similar or lower using a sit-stand-support compared to sitting or standing. The activity of the m. gastrocnemius was in between the levels of sitting or standing. No significant differences were observed for the performance. The sit-stand-support most often was preferred to sitting. A stable sit-stand-support may be a solution for short interruptions of sitting or standing. Relevance to industryA stable sit-stand-support may be an option for short interruptions of sitting and standing and may reduce the consequences of these static positions.

Effect of Fatigue on Leg Muscle Activation and Tibial Acceleration during a Jumping Task

Effect of Fatigue on Leg Muscle Activation and Tibial Acceleration during a Jumping Task

Do Young People Ever Sit Still? Variations in Accelerometer Counts, Muscle Activity and Heart Rate across Various Sedentary Activities in Youth.

Evidence of adverse health effects of TV viewing is stronger than for overall sedentary behaviour in youth. One explanation may be that TV viewing involves less body movement than other sedentary activities. Variations in body movement across sedentary activities are currently unknown, as are age differences in such variations. This study examined body movement differences across various sedentary activities in children and adolescents, assessed by hip-, thigh- and wrist-worn accelerometers, muscle activity and heart rate. Body movement differences between sedentary activities and standing were also examined. Fifty-three children (aged 10–12 years) and 37 adolescents (aged 16–18 years) performed seven different sedentary activities, a standing activity, and a dancing activity (as a control activity) in a controlled setting. Each activity lasted 10 minutes. Participants wore an Actigraph on their hip and both wrists, an activPAL on their thigh and a heart rate monitor. The muscle activity of weight-bearing leg muscles was measured in a subgroup (n = 38) by surface electromyography. Variations in body movement across activities were examined using general estimation equations analysis. Children showed significantly more body movement during sedentary activities and standing than adolescents. In both age groups, screen-based sedentary activities involved less body movement than non-screen-based sedentary activities. This may explain the stronger evidence for detrimental health effects of TV viewing while evidence for child sedentary behaviour in general is inconsistent. Differences in body movement during standing and sedentary activities were relatively small. Future research should examine the potential health effects of differences in body movement between screen-based versus non-screen based and standing versus sedentary activities.

Effect of Instability in Legpress Testing on Strength &amp; Muscle Activity in Functional Ankle Instability

Compensating instable situations is an important functional capability to maintain joint stability, to compensate perturbations and to prevent (re-)injury. Therefore, a reduced maximum strength and altered neuromuscular activity is expected by inducing instability to high loading test situations. Possible effects are not clear for induced instability during maximum legpress tests in healthy and furthermore in subjects with functional ankle instability (FAI). PURPOSE: First, to compare maximum strength and lower leg muscle activity between stable (S) and unstable (UN) maximum legpress tests. Second, to evaluate the association between FAI and effect of instability during testing. METHODS: 18 male subjects (12 healthy/6 subjective FAI, age: 28±4yrs, height: 180±8cm, weight: 80±9kg, physical activity: 6±5h/wk) were included and their ankle function was quantified by the Foot and Ankle measure (FAAM) questionnaire. Five maximum strength test with leg press isokinetic device in concentric (CON) and eccentric (ECC) mode were measured. Muscle activity were recorded by EMG of m. tibialis anterior (TA), m. peroneus longus (PL) and m. soleus (SOL). Peak force (FPeak, Nm) for maximum strength and root mean square (RMS, Hz) for EMG amplitude of TA, PL and SOL were calculated. Comparisons of conditions (S vs UN) were analyzed descriptively and with paired T-tests. For association, Pearson correlation was applied using FAAM score and RMS differences (condition UN – S). RESULTS: UN lead to a significant peak force reduction of 10.1% (CON) and 13.7% (ECC) significantly (p<0.001). RMS of PL in CON and TA in CON and ECC mode were 26.2%, 59.7% and 35.8% respectively significant higher in UN footplate in comparison with S (p<0.01). In addition, no correlations between FAI and loss of strength or changes in muscle activity have been found. CONCLUSION: Reduction in peak force and increased muscle activity confirmed the expected increased effort to compensate instability. The missing association between FAI and amount of altered strength or muscle activity might be attributed to a low level of FAI in the included subjects.

Evaluation of a passive exoskeleton for static upper limb activities

The aim of this study was to evaluate the effect of a passive upper body exoskeleton on muscle activity, perceived musculoskeletal effort, local perceived pressure and subjective usability for a static overhead task. Eight participants (4 male, 4 female) held a load (0 kg and 2 kg) three times overhead for a duration of 30 s each, both with and without the exoskeleton. Muscle activity was significantly reduced for the Biceps Brachii (49%) and Medial Deltoid (62%) by the device for the 2 kg load. Perceived effort of the arms was significantly lower with the device for the 2 kg load (41%). The device did not have a significant effect on trunk or leg muscle activity (for the 2 kg load) or perceived effort. Local perceived pressure was rated below 2 (low pressure levels) for all contact areas assessed. Half of the participants rated the device usability as acceptable. The exoskeleton reduced muscle activity and perceived effort by the arms, and had no significant negative effect on the trunk and lower body with regards to muscle activity, perceived effort and localised discomfort.

Effect of wobble board training on movement strategies to maintain equilibrium on unstable surfaces

Standing on unstable surfaces requires more complex motor control mechanisms to sustain balance when compared to firm surfaces. Surface instability enhances the demand to maintain equilibrium and is often used to challenge balance, but little is known about how balance training affects movement strategies to control posture while standing on unstable surfaces. This study aimed at assessing the effects of isolated wobble board (WB) training on movement strategies to maintain balance during single-leg standing on a WB. Twenty healthy men were randomly assigned to either a control or a training group. The training group took part in four weeks of WB training and both groups were tested pre and post the intervention. Electromyography from the supporting lower limb muscles, full-body kinematics and ground reaction forces were recorded during firm surface (FS) and WB single-leg standing. WB training did not affect FS performance (p = 0.865), but tripled WB standing time (p < 0.002). Moreover, training decreased lower leg muscle activation (29–59%), leg and trunk velocities (30% and 34%, respectively), and supporting limb angular velocity (24–47% across all planes for the ankle, knee and hip joints). Post intervention standing time was significantly correlated with angular velocities at the hip (r = 0.79) and knee (r = −0.83) for controls, while it correlated significantly with contra-lateral leg (r ∼ 0.70) and trunk velocity (r = −0.74) for trained participants. These results support the assumption that WB training enhances the ability to control counter-rotation mechanisms for balance maintenance on unstable surfaces, which may be a crucial protective factor against sports injuries.

The Effect of Kick Type on the Relationship between Kicking Leg Muscle Activation and Ball Velocity

The Effect of Kick Type on the Relationship between Kicking Leg Muscle Activation and Ball Velocity

Effects of wearing lower leg compression sleeves on locomotion economy

ABSTRACTThe purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p < 0.05, ηp2 > 0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

Bipedal robotic walking control derived from analysis of human locomotion

This paper proposes the design of a bipedal robotic controller where the function between the sensory input and motor output is treated as a black box derived from human data. In order to achieve this, we investigated the causal relationship between ground contact information from the feet and leg muscle activity n human walking and calculated filter functions which transform sensory signals to motor actions. A minimal, nonlinear, and robust control system was created and subsequently analysed by applying it to our bipedal robot RunBot III without any central pattern generators or precise trajectory control. The results demonstrate that our controller can generate stable robotic walking. This indicates that complex locomotion patterns can result from a simple model based on reflexes and supports the premise that human-derived control strategies have potential applications in robotics or assistive devices.

Closed-loop control of trunk posture improves locomotion through the regulation of leg proprioceptive feedback after spinal cord injury

After spinal cord injury (SCI), sensory feedback circuits critically contribute to leg motor execution. Compelled by the importance to engage these circuits during gait rehabilitation, assistive robotics and training protocols have primarily focused on guiding leg movements to reinforce sensory feedback. Despite the importance of trunk postural dynamics on gait and balance, trunk assistance has comparatively received little attention. Typically, trunk movements are either constrained within bodyweight support systems, or manually adjusted by therapists. Here, we show that real-time control of trunk posture re-established dynamic balance amongst bilateral proprioceptive feedback circuits, and thereby restored left-right symmetry, loading and stepping consistency in rats with severe SCI. We developed a robotic system that adjusts mediolateral trunk posture during locomotion. This system uncovered robust relationships between trunk orientation and the modulation of bilateral leg kinematics and muscle activity. Computer simulations suggested that these modulations emerged from corrections in the balance between flexor- and extensor-related proprioceptive feedback. We leveraged this knowledge to engineer control policies that regulate trunk orientation and postural sway in real-time. This dynamical postural interface immediately improved stepping quality in all rats regardless of broad differences in deficits. These results emphasize the importance of trunk regulation to optimize performance during rehabilitation.

Control of vertical posture while standing on a sliding board and pushing an object.

Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that induces translational perturbation). Thirteen healthy young participants were instructed to push a handle with both hands while standing on a sliding board that was either free to move in the anterior-posterior direction or stationary. Electromyographic activity (EMG)of trunk and lower extremity muscles, center of pressure (COP) displacements, and the forces exerted by the hand were recorded and analyzed during the APA and CPA phases. When the sliding board was free to move during pushing (translation perturbation), onsets of activity of ventral leg muscles and COP displacement were delayed as compared to pushing when standing on a stationary board. Moreover, magnitudes of shank muscle activity and the COP displacement were decreased. When pushing heavier weight, magnitudes of muscle activity, COP displacement, and pushing force increased. The magnitude of activity of the shank muscles during the APA and CPA phases in conditions with translational perturbation varied with the magnitude of the pushing weight. The outcome of the study suggests that the central nervous system prioritizes the pushing task while attenuates the source of additional perturbation induced by translation perturbation. These results could be used in the development of balance re-training paradigms involving pushing weight while standing on a sliding surface.

Motor unit discharge characteristics and walking performance of individuals with multiple sclerosis.

Walking performance of persons with multiple sclerosis (MS) is strongly influenced by the activation signals received by lower leg muscles. We examined the associations between force steadiness and motor unit discharge characteristics of lower leg muscles during submaximal isometric contractions with tests of walking performance and disability status in individuals who self-reported walking difficulties due to MS. We expected that worse walking performance would be associated with weaker plantar flexor muscles, worse force steadiness, and slower motor unit discharge times. Twenty-three individuals with relapsing-remitting MS (56 ± 7 yr) participated in the study. Participants completed one to three evaluation sessions that involved two walking tests (25-ft walk and 6-min walk), a manual dexterity test (grooved pegboard), health-related questionnaires, and measurement of strength, force steadiness, and motor unit discharge characteristics of lower leg muscles. Multiple regression analyses were used to construct models to explain the variance in measures of walking performance. There were statistically significant differences (effect sizes: 0.21-0.60) between the three muscles in mean interspike interval (ISI) and ISI distributions during steady submaximal contractions with the plantar flexor and dorsiflexor muscles. The regression models explained 40% of the variance in 6-min walk distance and 47% of the variance in 25-ft walk time with two or three variables that included mean ISI for one of the plantar flexor muscles, dorsiflexor strength, and force steadiness. Walking speed and endurance in persons with relapsing-remitting MS were reduced in individuals with longer ISIs, weaker dorsiflexors, and worse plantar flexor force steadiness. NEW & NOTEWORTHY The walking endurance and gait speed of persons with relapsing-remitting multiple sclerosis (MS) were worse in individuals who had weaker dorsiflexor muscles and greater force fluctuations and longer times between action potentials discharged by motor units in plantar flexor muscles during steady isometric contractions. These findings indicate that the control of motor unit activity in lower leg muscles of individuals with MS is associated with their walking ability.

Effects of Carrying Out a Low-Intensity Isometric Contraction of the Proximal Thigh Muscles on the Electromyographic Activity of the Leg Muscles when Simulating an Ankle Sprain

Background: The patterns of activation of the leg musculature can be altered after suffering from a sprained ankle, which can contribute negatively to the biomechanics of the leg. Ankle sprains can generate changes in muscle electromyographic activity in both the thigh and ankle regions, for which physiotherapy is the most common treatment. This study aimed to determine the effect of a low-intensity isometric contraction of the proximal thigh muscles (gluteus maximus (Gmax), gluteus medius (Gmed), tensor fasciae latae (TFL) on the electromyographic response of the tibialis anterior (TA), peroneus longus (PL), lateral gastrocnemius (LG), and soleus muscles (SL) in a sudden ankle supination. Methods: Fifteen healthy volunteers were subjected to 2 series of three trials on a sudden ankle supination platform (50°). This involved a multiple analysis of variance per trial and muscle for the dependent variables and an analysis of variance in the measures repeated under study for the different time windows evaluated, according to the intended factors and muscle studied. Results: No significant differences were observed in the variables concerning the time of activation, the moment of maximum EMG registration or registered peak value. Conclusion: Inducing a low-intensity isometric contraction of the abductor leg muscles did not generate changes in the muscular values studied.

Characteristics of Lower Leg Muscle Activity in Patients with Cerebral Palsy during Cycling on an Ergometer.

Purpose Cycling on ergometer is often part of rehabilitation programs for patients with cerebral palsy (CP). The present study analyzed activity patterns of individual lower leg muscle during active cycling on ergometer in patients with CP and compared them to similar recordings in healthy participants. Methods Electromyographic (EMG) recordings of lower leg muscle activity were collected from 14 adult patients and 10 adult healthy participants. Activity of the following muscles was recorded: Musculus tibialis anterior, Musculus gastrocnemius, Musculus rectus femoris, and Musculus biceps femoris. Besides qualitative analysis also quantitative analysis of individual muscle activity was performed by computing the coefficient of variation of EMG signal amplitude. Results More irregular EMG patterns were observed in patients in comparison to healthy participants: agonist-antagonist cocontractions were more frequent, muscle activity measured at specific points of the cycle path was more variable, and dynamic range of muscle activity along the cycle path was narrower in patients. Hypertonicity was also more frequent in patients. Conclusion Muscle activity patterns during cycling differed substantially across patients. It showed irregular nature and occasional sharp high peaks. Dynamic range was also narrower than in controls. Observations underline the need for individualized cycling training to optimize rehabilitation effects.

Assessment of leg muscle activity using toe tapping in patients with Parkinson's disease: comparison of two types of toe tapping.

[Purpose] This study investigates two types of toe tapping, i.e., “closed,” with both feet on the floor, and “open,” in which the foot does not touch the ground, and evaluates their usefulness in combination with monitoring of muscle activity during toe tapping. [Subjects and Methods] The study enrolled 11 patients with Parkinson’s disease (PD) and 9 controls (Controls). The tibialis anterior (TA) and gastrocnemius (GS) muscle activity during toe tapping was measured using surface electromyography. [Results] In closed tapping, the minima in GS activation with the first tap was significantly higher in patients with PD than in Controls. In open tapping, the coefficient of variation (CV) of local maxima in TA activation was significantly higher in patients with PD than in Controls. In both types of tapping, the CV of extrema in GS activities increased with disease duration, but this may be due to the long-term administration of Levodopa, which itself tends to cause excessive GS activities. [Conclusion] Closed tapping is suitable for the assessment of GS activity and can detect excessive activities, which is observed as visible movement. Open tapping, on the other hand, is suitable for assessment of TA activity.

Weight bearing exercise can elicit similar peak muscle activation as medium-high intensity resistance exercise in elderly women.

To assess whether stepping-based weight bearing exercise (WBE) can elicit peak activation of upper leg muscles similar to resistance exercise (RE) at an intensity required to induce strength gains in elderly women. Muscular activation of several upper leg muscles was measured during RE and WBE in a cohort of 19 healthy elderly women (69.3 ± 3.4years). WBE consisted of forward and lateral stepping with step heights of 10, 20 and 30cm. Muscular activation was compared to 60% of one-repetition maximum (1-RM) of congruent RE. Peak activation during WBE was higher than RE at 60% 1-RM during forward and lateral stepping in vastus lateralis starting at 20cm (p = 0.049 and p = 0.001), and biceps femoris at 30cm step height (p = 0.024 and p = 0.030). Gluteus maximus peak activation matched RE at 60% 1-RM at 20 and 30cm step height regardless of step direction (p ≥ 0.077). Peak activation of the rectus femoris and gluteus medius matched RE activation at 60% 1-RM during lateral stepping at 30cm (p = 0.355 and p = 0.243, respectively) but not during forward stepping. WBE did not induce similar activation as RE in the semitendinosus. In WBE, most upper leg muscles were recruited at an equal or higher intensity than in RE at 60% 1-RM. Lateral stepping at 30cm step height showed the highest training potential of all WBE's applied.