Lower Limb Muscle Activation Patterns Research Articles

Gait and sEMG characteristics of lower limbs in children with unilateral spastic cerebral palsy during walking

BackgroundChildren with unilateral spastic cerebral palsy (USCP) have muscle hypertonia, balance, and coordination defects that affect gross motor skills, especially walking. Understanding the gait characteristics and lower limb muscle activation patterns of USCP children can provide an objective and quantitative basis for patient assessment and treatment plan formulation. ObjectiveThis study compared the gait and lower limb muscle activation characteristics of children with USCP and with typical development (TD) during walking. MethodsWe recorded gait and sEMG data of 20 children with USCP, and 20 with typical development. sEMG signals were acquired from the bilateral tibialis anterior (TA) and lateral gastrocnemius muscles (LG) during walking. The root mean square (RMS) value, integrated electromyographic (iEMG) value and co-contraction ratio (CR) were used to evaluate muscle activity. Student's t Test and non-parametric rank sum Test were used to compare the differences between the data groups (significance level of 0.05). ResultsThe stance time, step length, speed, single leg support time ratio, ground impact, pre-swing angle, and muscle strength of the affected side were significantly decreased compared to those of the unaffected side in children with USCP (P < 0.05), while the swing phase, muscle tonus of LG were significantly prolonged (P < 0.05). Compared with TD children, children with USCP exhibited reduced bilateral walking ability, particularly noticeable in their smaller pre-swing angle(P < 0.05), diminished muscle strength of the TA and LG, as well as LG spasms(P < 0.05). SignificanceChildren with USCP have decreased ambulatory gait stability. Step length, pull acceleration, pre-swing angle, and CR can be used as sensitive indicators for gait assessment. Strengthening the TA muscle and reducing ankle spasm may help improve gait and postural stability in children with USCP.

Age-related differences in lower limb muscle activation patterns and balance control strategies while walking over a compliant surface

Substantial evidence demonstrates that falls in older adults are leading causes of fatal and non-fatal injuries and lead to negative impacts on the quality of life in the aging population. Most falls in older fallers result from unrecoverable limb collapse during falling momentum control in the single limb support (SLS) phase. To understand why older adults are more likely to fall than younger adults, we investigated age-related differences in knee extensor eccentric control, lower limb muscle activation patterns, and their relation to balance control. Ten older and ten younger healthy adults were compared during balance control while walking on a compliant surface. There was a positive correlation between knee extensor eccentric work in the perturbed leg and the swinging leg’s speed and margin of stability. In comparison to younger adults, older adults demonstrated (1) less eccentric work, reduced eccentric electromyography burst duration in the perturbed leg, (2) higher postural sway during SLS, and (3) impaired swinging leg balance control. The group-specific muscle synergy showed that older adults had a prominent ankle muscle activation, while younger adults exhibited a more prominent hip muscle activation. These findings provide insight into targeted balance rehabilitation directions to improve postural stability and reduce falls in older adults.

Lower limb muscle activation pattern in male soccer players with lumbar hyperlordosis

Objectivethe aim of the current study was to compare the lower limb muscle activation pattern in soccer players with and without lumbar hyperlordosis during single-leg squat performance. Methodsthirty male collegiate soccer players (15 with and 15 without lumbar hyperlordosis) performed the SLS task. Surface EMG was used to record the activation of eleven lower limb muscles. The activation of these muscles reduces to 100 points during the SLS cycle, where 50% demonstrates the maximum knee flexion, and 0% and 99% demonstrate the maximum knee extension. Resultssoccer players with lumbar hyperlordosis had higher muscle activation than those with normal lumbar lordosis in gluteus maximus, biceps femoris, and medial gastrocnemius. By contrast, they had lower gluteus medius, vastus medialis oblique, rectus femoris, soleus, and medial gastrocnemius (only in the final ascent phase of the SLS) muscle activity than the normal group during the SLS. Conclusionthis alteration may negatively affect targeted muscle performance during the SLS. Subsequent study is required to specify whether such an alteration in the lower limb muscle could be accompanied by injury in soccer players and change in their athletic performance.

Comparison of Lower Limb Muscle Activation Patterns in Different Foot Structures using Voluntary Response Index: A Study Protocol

Background: Structural foot disorders can widely contribute to lower limb musculoskeletal conditions. Some researchers consider them the origin of overuse injuries in lower limbs. Although their effects on electrical activities of intrinsic and extrinsic foot muscles are well-established, their impact on other lower limb muscle groups are yet to be clarified.&#x0D; Objectives: This study aims to identify the activation patterns of lower limb muscle groups in various foot structures.&#x0D; Materials and Methods: In this case control study, 45 asymptomatic male and female subjects with different foot structures (pronated, supinated, and normal) will be selected using non-random sampling. The electrical activities of the gluteus medius, vastus lateralis and medialis, biceps femoris, semitendinosus, and lateral and medial gastrocnemius muscles will be examined during a jump-landing task. Voluntary response index, including magnitude and similarity index, will be subsequently calculated.&#x0D; Discussion: While several studies have evaluated the activation of lower limb muscles in different foot structures, they have solely focused on foot muscles. In contrast, the present study will assess activation patterns of the global lower limb muscles using the voluntary response index.

Temporal differences in the myoelectric activity of lower limb muscles during rearfoot and forefoot running: A statistical parametric mapping approach

The aim of this study was to apply statistical parametric mapping (SPM) to compare temporal changes in EMG amplitude between rearfoot (RF) and forefoot (FF) running techniques. Eleven recreational runners ran on a treadmill at a self-selected speed, once using a RF strike pattern and once using a FF strike pattern (randomized order). The myoelectric activity of five lower limb muscles [rectus femoris (RFe), biceps femoris (BF), tibialis anterior (TA), medial and lateral gastrocnemius (MG and LG)] was evaluated, using bipolar electromyography (EMG). EMG data from the RF and FF running techniques was then processed and posteriorly compared with SPM, dividing the analysis of the running cycle into stance and swing phases. The MG and LG muscles showed higher activation during FF running at the beginning of the stance phase and at the end of the swing phase. During the end of the swing phase the TA muscle’s EMG amplitude was higher, when the RF running technique was used. A higher level of co-activation between the gastrocnemius and TA muscles was observed at the end of the swing phase during RF running. The myoelectric behaviour of the RFe and BF muscles was similar during both running techniques. These findings highlight the importance of SPM for the accurate assessment of differences in muscle activity during running and strongly suggest that these two running techniques predominately reflect adjustments of the leg and not the thigh muscles.

Wavelet analysis reveals differential lower limb muscle activity patterns long after anterior cruciate ligament reconstruction

The purpose of this study was to test whether differences in muscle activity patterns between anterior cruciate ligament-reconstructed patients (ACLR) and healthy controls could be detected 10 to 15 years post-surgery using a machine learning classification approach. Eleven ACLR subjects and 12 healthy controls were recruited from an ongoing prospective randomized clinical trial. Surface electromyography (EMG) signals were recorded from gastrocnemius medialis and lateralis, tibialis anterior, vastus medialis, rectus femoris, biceps femoris, and semitendinosus muscles. Muscle activity was analyzed using wavelet analysis and examined within four sub-phases of the hop test, as well as an average of the task as a whole. K-nearest neighbor machine learning combined with a leave-one-out validation was used to classify the muscle activity patterns as either ACLR or Control. When muscle activity was averaged across the whole hop task, activity patterns for all muscles except the tibialis anterior were identified as being different between the study cohorts. ACLR patients demonstrated continuous muscle activities that spanned take-off, airborne, and landing hop phases versus healthy controls who displayed timed and regulated islets of muscle activities specific to each hop phase. The most striking features were 25–50% greater relative quadriceps intensity and approximately 66% diminished biceps femoris intensity in ACLR patients. The current findings are in contrast to previous work using conventional co-contraction and muscle activation onset EMG measures of the same dataset, underscoring the sensitivity and potential of the wavelet approach coupled with machine learning to reveal meaningful adaptation strategies in this at-risk population.

Lower limb muscle activation patterns in ice-hockey skating and associations with skating speed

ABSTRACT In this study, we aimed to describe lower limb kinematic and muscle activation patterns and then to examine the potential associations between those variables and skating speed in highly trained ice-hockey players. Twelve players (age 18.4–22.0 years) performed five maximal 30-metre forward skating sprints. Skating speeds, muscle activities from eight lower limb muscles (gluteus maximus, gluteus medius, adductor magnus, rectus femoris, vastus lateralis, biceps femoris, tibialis anterior and soleus), and sagittal plane joint angles from the hip and knee joint were measured. A lower activity of the gluteus maximus (r = −0.651, p = 0.022, β = −0.08) and a reduced gluteus maximus to rectus femoris coactivity (r = −0.786, p = 0.002, β = −3.26) during the recovery phase were found to be associated with faster skating speed. No significant associations were observed between sagittal plane hip and knee kinematics and skating speed. This study provides evidence that muscle activities during the recovery phase of skating may have an important role in skating performance.

Understanding Human Neural Control of Short-term Gait Adaptation to the Split-belt Treadmill

Many studies of split-belt treadmill adaptation have been focused on the biomechanical changes that occur in response to walking on belts at different speeds. This process of adaptation, and the ensuing aftereffects that are present when participants return to typical treadmill walking, have inspired the potential use of the split-belt treadmill as a rehabilitation tool. However, a full systematic review of the current split-belt treadmill literature has not yet been published to consolidate what is known about how the human central nervous system (CNS) controls adaptation to this type of symmetry perturbation. A systematic literature search identified 55 studies that investigated the neural control of human gait adaptation to a split-belt treadmill. Studies of infants and manipulated sensory feedback in healthy adults suggest that the initial gait adjustments to split-belt walking are reliant on proprioceptive feedback to inform central pattern generators to modify lower limb muscle activation patterns appropriately. Simultaneously, this literature suggested that proprioceptive and visual feedback inform supraspinal centres for motor planning and motor output to adapt and store a new and efficient gait pattern to walk on belts at different speeds. However, evidence from participants with brain injury (post-stroke, cerebellar lesions) suggest that injury impedes, but does not completely take away, the ability to adjust and adapt aspects of the gait pattern to split-belts. The model proposed from this review provides the overarching roles of the CNS in the adaptation process, specifically in short-term, and potential sites of focus within the human CNS for future rehabilitation-based work.

A Robotic Gait Training System with Stair-climbing Mode Based on a Unique Exoskeleton Structure with Active Foot Plates

This paper introduces a newly developed robotic gait training system for lower-limb rehabilitation of stroke patients. The system (Cyborg-Trainer L; Cyborg-Lab Co., Korea) provides a stair-climbing mode in addition to the conventional level-walking mode by leveraging a unique exoskeleton structure with separately operable foot plates. Unlike conventional end-effector type gait training robots, the subject’s feet are not constrained by foot plates, but are free to emulate the ground or a set of stairs. The ground reaction force is measured by force sensors in the foot plates and utilized to compensate for the vertical movement of pelvis. The exoskeleton structures are connected at hip, knee, and ankle joints, and these can support a patient’s weight to ensure a normal gait pattern. The system has four control modes with different levels of assistive or resistance force. To show the feasibility of the developed training mode, a series of experiments measuring muscle activity were conducted during 1) level-walking with the robot, 2) level-walking on a treadmill without a robot, 3) stair-climbing with the robot, and 4) actual stairclimbing without a robot. The muscle activation from the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius medialis of the dominant leg of five healthy adults were measured and analyzed. Results showed that all muscles had a rhythmic muscle activation pattern. Even though muscle activation patterns were different between gaits using the robotic gait system and those not using it, reduced amplitudes and phasic muscle activations were observed during the training in the robotic system. The developed system is a new type of robotic gait training system that could induce phasic lower limb muscle activation patterns, and its clinical efficacy will be validated in clinical trials after regulatory approval.

Effects of Ankle Joint Motion on Pelvis-Hip Biomechanics and Muscle Activity Patterns of Healthy Individuals in Knee Immobilization Gait.

The purpose of the study was to investigate the pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between healthy people walking in two gaits and evaluate the effects of ankle joint motion on these two gaits. The two gaits included walking with combined knee and ankle immobilization and with individual knee immobilization. Ten healthy participants were recruited and asked to walk along a 10 m walk away at their comfortable speeds in the two gaits. Kinematic data, ground reaction force, and electromyography waveforms of trunk and lower limb muscles on the right side were collected synchronously. Compared to individual knee immobilization gait, people walking in the combined knee and ankle immobilization gait increased the range and average angle of the anterior pelvic tilt during the first double support and the single support phase, respectively. The combined knee and ankle immobilization gait also increased the range of hip abduction during the second double support phase. These kinematic alternations caused changes in trunk and lower limb muscle activity patterns. The ankle immobilization increased the range of gluteus maximus activation in the first double support phase, the range of rectus abdominis activation, the average amplitude of rectus femoris activation in the single support phase, and the range of rectus femoris activation in swing phase and decreased the range of and tibialis anterior activation in the first double support phase. The ankle immobilization also increased the average values of proximodistal component in AKI gait during the single support phase. This study revealed significant differences in pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between the two gaits.

Characterization of lower limb muscle activation patterns during walking and running with Intravoxel Incoherent Motion (IVIM) MR perfusion imaging

BackgroundThe distribution of energy use among different lower limb muscles during walking and running is not well understood. Local blood flow within skeletal muscle tissue depends on its metabolic activity during activation. The non-invasive magnetic resonance microvascular perfusion method Intravoxel Incoherent Motion (IVIM) is able to quantify muscle activation. PurposeTo non-invasively determine quantitative changes in local microvascular perfusion and blood flow via IVIM in order to characterize specific muscle activation of the lower limb at rest, during walking and during running. Methods3 T MR IVIM diffusion-weighted images of N = 16 lower extremities (bilateral imaging of n = 8 healthy volunteers; mean age 27.5 ± 5.7 years) were acquired at rest and immediately after walking and running for 15 min, respectively. A transverse monopolar pulsed gradient fat suppressed spin echo EPI sequence was used (9 b-values from 0 to 1000s/mm2, 3 orthogonal directions). Anatomical transverse T1-weighted turbo SE images were acquired at rest. Muscles at the pelvis, thigh and lower leg were segmented. IVIM perfusion parameters f, D* and fD* and the diffusion coefficient D were obtained after standard two-steps fitting of the IVIM bi-exponential signal equation. Descriptive statistics, t-tests, Pearson's correlations and Partial Spearman correlations were used for statistical analyses. ResultsThe microvascular blood flow (fD*) increased significantly and stepwise from rest (1.65 ± 0.83*10−3 mm2/s) to walking (1.99 ± 0.80*10−3 mm2/s, P < 0.001) and running (2.18 ± 0.98*10−3 mm2/s, P < 0.001). The perfusion increase was most pronounced for lower leg and feet muscles (P < 0.001). Hamstring muscles showed a higher microvascular perfusion increase than quadriceps muscles (P < 0.05). A higher increase of the heartrate from walking to running correlated significantly with a lower increase of fD* from walking to running (R = -0.16, P = 0.001). ConclusionIVIM MRI quantitatively measures local microvascular muscle perfusion to detect muscle activation patterns through walking and running. A redistribution of blood flow towards the lower leg was observed during running as compared to walking.

Effect of Kinesio taping on electromyographic activity of leg muscles during gait in children with developmental coordination disorder: A randomized controlled trial.

Objective:This study aimed to evaluate the effectiveness of Kinesio tape (KT) on lower limb muscle activation pattern in children with developmental coordination disorder (DCD) during walking.Design:A parallel-group randomized controlled trial.Setting:University laboratory setting.Participants:Twenty-five children with DCD were randomly allocated to the KT group (mean age = 7.97 years) and 24 to the control group (mean age = 8.04 years).Intervention:KT group received KT application to the quadriceps and gastrocnemius muscles whereas the control group received no intervention.Measurements:Peak muscle activation (in percentage of maximal voluntary isometric contraction [%MVIC]) in the lower limbs during gait was measured by means of surface electromyography, electrogoniometry, and foot contact switches.Results:Gastrocnemius medialis activation during mid stance (23.46%MVIC, 95% CI = −32.53, −14.39) and late stance phases (3.25%MVIC, 95% CI = −5.67, −0.81) of gait increased after the application of KT in the KT group compared to baseline values. The KT group demonstrated 26.87%MVIC (95% CI = 26.87, 7.11) higher gastrocnemius medialis muscle peak activation during mid stance phase at post-test when compared with the control group. Moreover, gastrocnemius medialis and biceps femoris muscle peak activation during loading response decreased by 8.36%MVIC (95% CI = 2.71, 14.02) and 3.54%MVIC (95% CI = 1.08, 6.01), respectively, in the control group overtime.Conclusions:The application of KT on children with DCD had an increased gastrocnemius medialis muscle activation during stance phase. KT could be incorporated into gait re-education programmes to facilitate muscle contraction in these children.

Effects of transcranial direct current stimulation on gait in people with Parkinson\u2019s disease: study protocol for a randomized, controlled clinical trial

BackgroundGait difficulties are common and frequently devastating to people with Parkinson’s disease (PD). These difficulties are often followed by an increased risk of falls, leading to injury, hospitalization and mortality. The dysfunction in the basal ganglia-thalamocortical motor circuits and reduced activity in the premotor and primary motor cortices has raised interest in transcranial direct current stimulation (tDCS) as an adjunct intervention in PD. tDCS might provide a potentially safe and non-invasive treatment by modulating cortical excitability and behavioural outcomes. The aim of this study is to compare the effects of different monopolar and bipolar montages of tDCS administered to the motor cortex and cerebellum on gait speed in PD.MethodsThis study will be conducted in a randomized, double-blind cross-over design. Eighteen participants diagnosed with Parkinson’s disease will receive anodal and sham tDCS (1 mA, 20 min, 10 × 4 cm2) over the premotor and primary motor cortices with the cathode over the cerebellum during treadmill walking. Three montages will be applied over three sessions and compared: anodal tDCS with a small active cathode (4 × 4 cm2); anodal tDCS with a large, functionally inert cathode (10 × 10 cm2); and sham tDCS. The primary outcome measure is gait speed, and secondary outcome measures include gait parameters (temporospatial, segmental, kinematic), the Timed Up and Go test and lower limb muscle activity patterns as measured by electromyography.DiscussionThis study will investigate the short-term effects of anodal tDCS over the premotor and primary motor cortices on gait abilities using monopolar and bipolar montages in people with PD. The outcomes will inform future studies aimed at inducing longer-lasting changes in neural excitability and performance using multisession tDCS designs in PD.Trial registrationAustralian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12618000063213. Registered on 17 January 2018. Retrospectively registered.

Abnormal muscle activation patterns are associated with chronic gait deficits following traumatic brain injury

BackgroundGait and balance disorders are common among individuals who have experienced a mild to moderate traumatic brain injury (TBI). However, little is known about how the neuromuscular control of gait is altered following a TBI. Research questionInvestigate the relationship between lower limb muscle activation patterns and chronic gait deficits in individuals who previously experienced a mild to moderate TBI. MethodsLower extremity electromyographic (EMG) signals were collected bilaterally during treadmill and overground walking in 44 ambulatory individuals with a TBI >1 year prior and 20 unimpaired controls. Activation patterns of TBI muscles were cross-correlated with normative data from control subjects to assess temporal phasing of muscle recruitment. Clinical assessments of gait and balance were performed using dynamic posturography, the dynamic gait index, six-minute walk test, and preferred walking speed. ResultsTBI subjects exhibited abnormal activation patterns in the tibialis anterior, medial gastrocnemius, and rectus femoris muscles during both overground and treadmill walking. Activation patterns of the vastus lateralis and soleus muscles did not differ from normal. There was considerable heterogeneity in performance on clinical balance and gait assessments. Abnormal muscle activation patterns were significantly correlated with variations in the dynamic gait index among the TBI subjects. SignificanceIndividuals who have experienced a prior TBI do exhibit characteristic changes in the temporal coordination of select lower extremity muscles, which may contribute to impairments during challenging walking tasks.

Lower limb muscle activation patterns during foot rotation gait modification in people with knee osteoarthritis

Lower limb muscle activation patterns during foot rotation gait modification in people with knee osteoarthritis

Effects of pelvic range of motion and lower limb muscle activation pattern on over-ground and treadmill walking at the identical speed in healthy adults.

[Purpose] Many studies have compared over-ground and treadmill walking, but the biomechanical relationship between the two gait modes is unclear. The aim of this study was to analyze differences in pelvic range of motion and lower limb muscles activity during over-ground and treadmill walking in healthy adults. Moreover, we aimed to analyze differences according to gender. [Subjects and Methods] Twenty-three healthy adults (9 men, 14 women) between 25 and 35 years of age walked at the identical speed for 30 seconds each in two difference gait modes. The pelvic range of motion were obtained by using three-axis accelerometer and lower limb muscle activation data were obtained by using wireless surface EMG. [Results] The results showed that pelvic obliquity showed a greater angular range of women than men, and the pelvic rotation decreased more in treadmill walking than over-ground walking. In the muscles activity, vastus lateralis and tibialis anterior increased, and gastrocnemius medialis decreased in treadmill walking than over-ground walking. [Conclusion] We conclude that treadmill walking reduces the range of motion of the pelvic and increases lower limb muscles activity therefore, when using treadmill for the purpose of rehabilitation at the clinic, consider this difference.

Electromiography comparison of distal and proximal lower limb muscle activity patterns during external perturbation in subjects with and without functional ankle instability

Ankle sprain is one of the most common injuries among athletes and the general population. Most ankle injuries commonly affect the lateral ligament complex. Changes in postural sway and hip abductor muscle strength may be generated after inversion ankle sprain. Therefore, the consequences of ankle injury may affect proximal structures of the lower limb. The aim is to describe and compare the activity patterns of distal and proximal lower limb muscles following external perturbation in individuals with and without functional ankle instability. The sample consisted of 16 women with functional ankle instability and 18 healthy women were recruited to participate in this research. The external perturbation via body jacket using surface electromyography, amplitude and onset of muscle activity of gluteus maximums, gluteus medius, tibialis anterior, and peroneus longus was recorded and analyzed during external perturbation. There were differences between the onset of muscles activity due to perturbation direction in the two groups (healthy and functional ankle instability). In the healthy group, there were statistically significant differences in amplitude of proximal muscle activity with distal muscle activity during front perturbation with eyes open and closed. In the functional ankle instability group; there were statistically significant differences in amplitude of proximal muscle activity with distal muscle activity during perturbation of the front and back with eyes open. There were statistically significant differences in the onset of muscle activity and amplitude of muscle activity, with-in and between groups (P<0.05). Therefore, in the presence of functional ankle instability, activation patterns of the lower limb proximal muscles may be altered.

A comparison of lower limb muscle activation pattern using voluntary response index between pronated and normal foot structures during forward jump landing

BackgroundPronated of the foot is one of the important factors contributing to musculoskeletal problems affecting the lower extremities. It is known that in a pronated foot, excessive mechanical load is applied to the lower limb structures which may result in altered biomechanics and muscle activation patterns. The aim of this study was to determine changes in the muscle activation pattern of the lower extremities in individuals with pronated, compared to normal, feet, using the voluntary response index (VRI). MethodsIn this cross sectional study, 15 asymptomatic pronated foot individuals (mean age 23.27 ± 3.28 years) and 15 normal subjects (mean age 23.40 ± 3.11 years) were recruited by simple non-random sampling. Electrical activities of gluteus medius (GM), vastus lateralis (VL), vastus medialis (VM), biceps femoris, semitendinosus (ST), and medial gastrocnemius (MG) muscles were recorded during a forward jump landing task. Voluntary response index (VRI) variables, included similarity index (SI) and magnitude (Mag) were also evaluated. ResultsMuscle activity of VM (p < 0.001) and ST (p = 0.010) were significantly higher but VL (p = 0.039) and MG (p = 0.001) were significantly lower in pronated foot, compared to normal subjects. Similarity index was found to be different (p < 0.001) between pronated foot and healthy individuals. No significant difference was found in terms of Mag between the two groups (p = 0.576). ConclusionThe altered pattern of lower limb muscle activation identified in the pronated foot during landing may be attributed to the different activation involving VL, VM, MG and ST muscles. Adaptations to the biomechanical effects, due to the pronated foot causing altered activation of VL, VM, MG, and ST muscles, results in an altered pattern of muscle activation. This change in activation pattern may harm the effectiveness of movement control processes; and might also predispose individuals with pronated feet, to injuries. It seems that an altered motor strategy with the aim of minimizing biomechanical changes, predisposes individuals to injuries. However, further large scale studies are needed to support the findings of the present study.

Differences in lower limb muscle activation patterns during Sit to Stand Task for different heel heights.

The purpose of this study was to investigate differences in lower limb muscle activation patterns for females wearing shoes with different heel heights during Sit to Stand Task (STS). Ten female participants with no prior history of neurological disorders participated in this study. Surface electromyography (sEMG) characteristics were recorded for four different heel heights (ranging from 4cm to 10cm) while performing the STS task. Signal processing analysis suggests that muscle activities increases on elevated heel heights, which may induce muscle imbalance for frequent STS tasks. In addition, results of muscle utilisation (percentage) for different heel heights suggest that lower limb muscles tend to compensate in order to maintain postural balance.

Does texting while walking really affect gait in young adults?

BackgroundTexting on a smartphone while walking has become a customary task among young adults. In recent literature many safety concerns on distracted walking have been raised. It is often hypothesized that the allocation of attentional resources toward a secondary task can influence dynamic stability. In the double task of walking and texting it was found that gait speed is reduced, but there is scarce evidence of a modified motor control strategy compromising stability. The aim of this study is twofold: 1) to comprehensively examine the gait modifications occurring when texting while walking, including the study of the lower limb muscle activation patterns, 2) to specifically assess the co-contraction of ankle antagonist muscles. We hypothesized that texting while walking increases co-contractions of ankle antagonist muscles when the body weight is transferred from one lower limb to the other, to improve the distal motor control and joint stabilization.MethodsFrom the gait data collected during an instrumented walk lasting 3 min, we calculated the spatio-temporal parameters, the ankle and knee kinematics, the muscle activation patterns of tibialis anterior, gastrocnemius lateralis, peroneus longus, rectus femoris, and lateral hamstrings, and the co-contraction (occurrence and duration) of the ankle antagonist muscles (tibialis anterior and gastrocnemius lateralis), bilaterally.ResultsYoung adults showed, overall, small gait modifications that could be mainly ascribable to gait speed reduction and a modified body posture due to phone handling. We found no significant alterations of ankle and knee kinematics and a slightly delayed activation onset of the left gastrocnemius lateralis. However, we found an increased co-contraction of tibialis anterior and gastrocnemius lateralis, especially during mid-stance. Conversely, we found a reduced co-contraction during terminal stance.ConclusionsOur results suggest that, in young adults, there is an adjustment of the motor control strategy aimed at increasing ankle joint stability in a specific and “critical” phase of the gait cycle, when the body weight is transferred from one leg to the other.