Tibialis Anterior Muscle Activity Research Articles

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P60. The effect of physical therapy on gait and balance in patients follow lumbar artificial disc replacement: a preliminary study

BACKGROUND CONTEXT Lumbar disc replacement (LDR) is used primarily to treat lumbar degenerative disc disease (DDD) resulting with back pain and/or leg pain in the absence of nerve root compression due to its advantages over fusion, including reduction of adjacent segment disease and reoperations as well as spinal motion preservation. A key factor of clinical success is rehabilitation. Physical therapy (PT) is often used to improve flexibility, strength and stability as well as balance and coordination, areas commonly deficient after surgery. Studies on PT and LDR are scarce. The impact of PT intervention on the neuromuscular, biomechanical, and self-reported outcomes of LDR patients’ gait and balance have not yet been explored. PURPOSE To evaluate the effect of PT on the biomechanics of the lower extremities and spine during gait and balance in patients with DDD after LDR surgical intervention. STUDY DESIGN/SETTING A prospective concurrent control cohort study. PATIENT SAMPLE Eight LDR patients. OUTCOME MEASURES Gait spatiotemporal parameters and center of mass (COM) and head sway during functional balance test along with VAS and ODI. METHODS After LDR surgery, gait and functional balance analyses were performed the week before PT (pre) and after completion of 6-8 weeks PT (post). PT consisted of manual therapy, therapeutic exercises and activities as well as neuromuscular education per LDR protocol, which focused on improved mobility, stability and strength as well as balance in accordance with appropriate precautions or restrictions. No modalities, except for cold packs, were used. Spatiotemporal parameters (ie, gait speed, cadence, stride length, width and time, etc.) were calculated during the gait evaluation. The functional balance test was similar to a Romberg's test. COM and head displacements in the sagittal and coronal planes and total sway amount were calculated. ODI and VAS were collected on the day of each testing. RESULTS ODI score was reduced from 29.3±22.8 to 15.5±2.5. VAS leg (pre: 3.3±2.3vs. post: 0.6±0.5), and lower back (pre: 3.6±2.9vs. post: 1.4±0.3) scores were reduce as well. Patients presented with less COM say in the forward–backward direction (pre: 1.27±1.11vs. post: 0.21±0.87 cm), less external oblique muscle (pre: 0.028±0.020vs. post: 0.009±0.003 mV) but more rectus femoris (pre: 0.009±0.004vs. post: 0.012±0.005 mV) and tibialis anterior (pre: 0.009±0.002vs. post: 0.012±0.001 mV) muscle activity after completion of PT in comparison to their pre-PT state. Gait spatiotemporal parameters did not significantly change completion of PT. This may be due to the small sample size we have. CONCLUSIONS This is the first study to explore the effect of PT treatment on function in patients with DDD after LDR surgery. Minimal information is available on the effect of PT and LDR. PT after LDR surgery may positively affect the COM sway and improved muscle recruitment of the tibialis anterior and rectus femoris during balance resulting with a more stable, efficient, and normal balance pattern. Gait appears intact after LDR. More research and standardization of PT care is needed for optimal LDR benefits.

ELECTROMYOGRAPHIC ACTIVITY OF VARIOUS MUSCLES DURING SIT-TO-STAND IN PATIENTS WITH STROKE: A META-ANALYSIS

Aims: To provide a comprehensive information about analysis of activation of various muscles during Sit-to-Stand in patients with stroke. To determine if there exists any common pattern of muscle activation. To give direction to future studies regarding the muscles to be investigated during Sit-to-Stand. Methods: literature search was performed with help of the most commonly used database i.e. PubMed to select the studies related to electromyographic activities of various lower extremity, trunk and upper extremity muscles during Sit-to-Stand activity, published till 2016. The Inclusion criteria for the study were Prospective or retrospective cohort studies, studies that included only participants with stroke leading to hemiparesis and/or along with healthy participants as control group and studies that measured the EMG activity in either trunk muscles and/or limb muscles during sit to stand. The exclusion criteria were if their population of interest also included patients with other neurological conditions and studies in any language other than English. Two independent investigators assessed the studies based on inclusion and exclusion criteria. Â Keywords used during the search were Electromyography, Stroke, Sit-to-Stand. The studies were thoroughly evaluated with respect to the Sit-to-Stand procedure and variety of muscles that were investigated through EMG analysis. Results: With the help of given keywords, abstracts/articles of 21 studies were retrieved from the database. After initial screening of the abstracts 12 studies were selected for in depth analysis. Various lower extremity muscles including Tibialis Anterior, Soleus, Quadriceps, Vastusmedialis, Gluteus Maximus were investigated in the studies. In 2 studies, Trunk muscles were investigated whereas in one study Triceps muscle activity was analyzed during Sit-to Stand activity in patients with stroke. Conclusion: From this study it can be concluded that the activity of Tibialis Anterior muscle was investigated more frequently by various researchers followed by the activity of Soleus and Quadriceps muscle.

Effects of a powered ankle-foot orthosis on perturbed standing balance

BackgroundLower extremity exoskeletons are mainly used to provide stepping support, while balancing is left to the user. Designing balance controllers is one of the biggest challenges in the development of exoskeletons. The goal of this study was to design and evaluate a balance controller for a powered ankle-foot orthosis and assess its effect on the standing balance of healthy subjects.MethodsWe designed and implemented a balance controller based on the subject’s body sway. This controller was compared to a simple virtual-ankle stiffness and a zero impedance controller. Ten healthy subjects wearing a powered ankle-foot orthosis had to maintain standing balance without stepping while receiving anteroposterior pushes. Center of mass kinematics, ankle torques and muscle activity of the lower legs were analyzed to assess the balance performance of the user and exoskeleton.ResultsThe different controllers did not significantly affect the center of mass responses. However, the body sway based controller resulted in a decrease of 29% in the biological ankle torque compared to the zero impedance controller and a decrease of 32% compared to the virtual-ankle stiffness. Furthermore, the soleus muscle activity of the left and right leg decreased on average with 8%, while the tibialis anterior muscle activity increased with 47% compared to zero impedance.ConclusionThe body sway based controller generated human-like torque profiles, whereas the virtual-ankle stiffness did not. As a result, the powered ankle-foot orthosis with the body sway based controller was effective in assisting the healthy subjects in maintaining balance, although the improvements were not seen in the body sway response, but in the subjects’ decreased biological ankle torques to counteract the perturbations. This decrease was a combined effect of decreased soleus muscle activity and increased tibialis anterior muscle activity.

The use of gait analysis in the assessment of patients afflicted with spinal disorders.

Use gait analysis to establish and detail the clinically relevant components of normal human gait, analyze the gait characteristics for those afflicted with spinal pathology, and identify those aspects of human gait that correlate with pre- and postoperative patient function and outcomes. Twenty patients with adult degenerative scoliosis (ADS), 20 patients with cervical spondylotic myelopathy (CSM), and 15 healthy volunteers performed over-ground gait trials with a comfortable self-selected speed using video cameras to measure patient motion, surface electromyography (EMG) to record muscle activity, and force plates to record ground reaction force (GRF). Gait distance and temporal parameters, ankle, knee, hip, pelvic, and trunk range of motion (ROM), duration of lower extremity EMG activity and peak vertical GRF were measured. Patients with ADS and CSM exhibited a significantly slower gait speed, decrease in step length, cadence, longer stride time, stance time, double support time, and an increase in step width compared to those in the control group. These patients also exhibited a significantly different ankle, knee, pelvic, and trunk ROM. Moreover, spinal disorder patients exhibited a significantly longer duration of rectus femoris, semitendinosus, tibialis anterior and medial gastrocnemius muscle activity along with an altered vertical GRF pattern. Gait analysis provides an objective measure of functional gait in healthy controls as well as those with ADS and CSM. This study established and detailed some of the important kinematic and kinetic variables of gait in patients with spinal disorders. We recommend that spine care providers use gait analysis as part of their clinical evaluation to provide an objective measure of function. These slides can be retrieved under Electronic Supplementary Material.

Investigating Tibialis Anterior Muscle Activity Levels in Patients With Genu Varum During Single-Leg Jump-Landing Task

Investigating Tibialis Anterior Muscle Activity Levels in Patients With Genu Varum During Single-Leg Jump-Landing Task

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

Intramuscular pressure (IMP) is the hydrostatic fluid pressure that is directly related to muscle force production. Electromechanical delay (EMD) provides a link between mechanical and electrophysiological quantities and IMP has potential to detect local electromechanical changes. The goal of this study was to assess the relationship of IMP with the mechanical and electrical characteristics of the tibialis anterior muscle (TA) activity at different ankle positions. We hypothesized that (1) the TA IMP and the surface EMG (sEMG) and fine-wire EMG (fwEMG) correlate to ankle joint torque, (2) the isometric force of TA increases at increased muscle lengths, which were imposed by a change in ankle angle and IMP follows the length-tension relationship characteristics, and (3) the electromechanical delay (EMD) is greater than the EMD of IMP during isometric contractions. Fourteen healthy adults [7 female; mean (SD) age = 26.9 (4.2) years old with 25.9 (5.5) kg/m2 body mass index] performed (i) three isometric dorsiflexion (DF) maximum voluntary contraction (MVC) and (ii) three isometric DF ramp contractions from 0 to 80% MVC at rate of 15% MVC/second at DF, Neutral, and plantarflexion (PF) positions. Ankle torque, IMP, TA fwEMG, and TA sEMG were measured simultaneously. The IMP, fwEMG, and sEMG were significantly correlated to the ankle torque during ramp contractions at each ankle position tested. This suggests that IMP captures in vivo mechanical properties of active muscles. The ankle torque changed significantly at different ankle positions however, the IMP did not reflect the change. This is explained with the opposing effects of higher compartmental pressure at DF in contrast to the increased force at PF position. Additionally, the onset of IMP activity is found to be significantly earlier than the onset of force which indicates that IMP can be designed to detect muscular changes in the course of neuromuscular diseases impairing electromechanical transmission.

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.

Comparison of tibialis anterior and gastrocnemius muscles activation on balance training devices and hoverboard

Balance training devices such as wobble board, basu ball and balance cushion are the tool use in balance training exercise programme in order to improve muscle strength and restore posture balance due degeneration of body function or injury. Recently, self-balancing scooter such as Segway and hover board showed a positive effects on rehabilitation. However, it is less known how these devices affect muscle physiological properties. This study aims to to measure ankle muscles activation on difference balance training devices and hover board. Besides, a comparison between these device will be done in order to identify if hover board has a promising feature to be an alternative balance training device. In this research, surface EMG (sEMG) was used to record tibialis anterior and gastrocnemius muscle activities. Seventeen healthy subjects were required to stand on three different types of balance training device such as wobble board, balance cushion, bosu ball and a hover board. They were asked to maintain their standing position on each devices for two minutes. Both time domain and frequency domain analysis were used to identify the features of the EMG signal. Time domain analysis measurement involved average rectified value (ARV) and root mean square (RMS), meanwhile for frequency domain, median frequency (MDF) of the signal were measured. The results shows that, the RMS is differed significantly between the balance training devices (p<0.05) for tibialis anterior muscle but not gastrocnemius muscle. Meanwhile, no significant difference between the devices in the ARV and the MDF value (p>0.05). Besides, less stable devices increased muscle activity were observed. There is not much difference between hover board and the other devices in term of physiological effects of both tibialis anterior and gastrochemious muscle. It is also suggested that hover board offers a promising feature to be an alternative device for balance training device.

Biomechanics analysis on muscle activation during jumping jack exercise

Journal of Sports Science and Physical Education 6(2): 28-35, 2017 – The purpose of this study was to investigate on muscle activities with electromyography (EMG) during jumping jack activity. The EMG sensors were placed on the interest muscle to measure the activity of gastrocnemius and tibialis muscles during jumping jack. Specific thresholds per muscle were applied on the EMG prior comparison. These thresholds were determined by EMG muscle activity. Overall, visual inspection showed comparable activity patterns. The mean absolute value (MAV) and root mean square (RMS) data were collected to show differences activation of both muscle. The results showed that there are distinct differences between gastrocnemius and tibialis anterior during jumping jack. Based on MAV and RMS data, the activation of tibialis anterior muscle is higher than gastrocnemius muscle during jumping jack activity. This conclude that the tibialis anterior muscle had significantly higher electromyography activity on jumping ja

Plantar pressure differences between cases with symptoms of clinically diagnosed chronic exertional compartment syndrome and asymptomatic controls

BackgroundAnterior chronic exertional compartment syndrome of the leg has been hypothesised to develop due to excessive muscle activity and foot pronation. Plantar pressure variables related to lower limb muscle activity and foot type may therefore provide insight into this condition. Methods70 male cases and 70 asymptomatic controls participated. A clinical diagnosis was established from typical symptoms, with clinical examination excluding other pathologies. Plantar pressure variables during walking, hypothesised to be related to foot type, toe extensor activity or had shown predictive validity for general exercise-related lower leg pain, were extracted. FindingsCases were shorter in height (mean difference 2.4cm), had greater body mass (mean difference 4.4kg) and had reduced ankle dorsiflexion range of motion than controls (mean difference 1.5cm). Plantar pressure variables indicative of foot-type and toe extensor activity did not differ between groups (P>0.05). The magnitude of medial forefoot loading was the strongest plantar pressure predictor of the presence of chronic exertional compartment syndrome (Odds ratio:0.87, P=0.005). There was also some evidence of greater lateral heel loading at 5% of stance time (P=0.049–0.054). InterpretationThe lack of association with foottype-related and toe extensor activity-related plantar pressure variables suggest that these are not risk factors for the development of chronic exertional compartment syndrome, contrary to earlier hypotheses. The greater lateral to medial loading could theoretically represent increased Tibialis anterior muscle activity at heel strike but a subsequent loss of control as the ankle is lowered. Future studies directly investigating muscle activity and function are now required.

Biomechanical differences between cases with suspected chronic exertional compartment syndrome and asymptomatic controls during running

Chronic exertional compartment syndrome (CECS) has been hypothesised, following clinical observations, to be the result of abnormal biomechanics predominantly at the ankle. Treatment of CECS through running re-education to correct these abnormalities has been reported to improve symptoms. However no primary research has been carried out to investigate the movement patterns of those with CECS. This study aimed to compare the running kinematics and muscle activity of cases with CECS and asymptomatic controls.20 men with bilateral symptoms of CECS of the anterior compartment and 20 asymptomatic controls participated. Barefoot and shod running 3D kinematics and muscle activity of the left and right legs; and anthropometry were compared.Cases displayed less anterior trunk lean and less anterior pelvic tilt throughout the whole gait cycle and a more upright shank inclination angle during late swing (peak mean difference 3.5°, 4.1° and 7.3° respectively). Cases demonstrated greater step length and stance time, although this was not consistent across analyses. There were no consistent differences in Tibialis anterior or Gastrocnemius medialis muscle activity. Cases were heavier (mean difference 7.9kg, p=0.02) than controls with no differences in height (p>0.05)These differences only partially match the clinical observations previously described. However, no consistent differences were found at the ankle joint suggesting that current running re-education interventions which focus on adjusting ankle kinematics are not modifying pathological aspects of gait. The longer step length is a continuing theme in this population and as such may be a key component in the development of CECS.

Developing interactive and simple electromyogram PONG game for foot dorsiflexion and plantarflexion rehabilitation exercise.

Gaming systems have been proven to be able to improve physical and cognitive skills. Several studies have integrated games to be part of rehabilitation program to improve functional ability of human limbs in performing activities of daily living. This paper presents the development of an interactive electromyogram (EMG) based PONG game for foot dorsifexion and plantarflexion exercise. PONG game is selected because it is a classical game that can be easily comprehended and can be played by young and old people. Two surface EMG sensors were used in this work to acquire muscle activity of tibialis anterior muscle and gastrocnemius muscle. An experimental study was carried out to examine the viability of this sensor as input to play the game. The results were satisfactory. This study further strengthens the viability of using muscle activity as an input for gaming system and as a mean to monitor patient rehabilitation progress.

Analysis of Tibialis Anterior and Gastrocnemius Muscle Activity According to Toe Angle during Gait

Background/Objectives: The purpose of this study was to determine the effects of changing the foot progression angle (FPA) on muscular activity of the lower extremity in 21 healthy male and female subjects in their 20s. Methods/Statistical analysis: After electromyographic (EMG) electrodes were positioned over the tibialis anterior (TA) and gastrocnemius (GCM) muscles, subjects underwent gait evaluation under three PFA magnitudes ( -10°, 10°, 30°) to measure the root mean square (RMS). Multivariate Analysis of Variance was used for statistical analysis along with Tukey's post-hoc test. An alpha of 0.5 is considered to be statistically significant. Findings: Comparison of changes in muscle activity of the TA and GCM during walking under different FPA magnitudes revealed no significant difference during –10° toe-in and 30° toe-out gaits. However, during 10° normal gait, the total activity of the two muscles was significantly lower on both sides in comparison with those found during –10° toe-in and 30° toe-out gaits. Improvements/Applications: It will be necessary to conduct further study with subjects who actually walk with either toe-in gait pattern or toe-out gait pattern to ensure the impact of their gait patterns.

The Effect of the Period Wearing High-heeled Shoes on Muscle Activity of Lower Extremity During Walking

본 연구는 하이힐을 신은 기간이 하지 근 활성화에 미치는 영향을 알아보기 위해 수행되었다. 대상자는 항공서비스학과에 재학 중인 여학생 34명이었으며 2그룹으로 분류되었다 : 대조군 - 16명으로 하이힐을 한 번도 신지 않은 자, 실험군 - 18명으로 하이힐을 1년간 꾸준히 신은 자. 근 활성화는 EMG를 사용하여 앞정강근, 장딴지근, 넙다리곧은근, 척추세움근에 패드를 붙이고 맨발로 걸을 때와 하이힐을 착용하고 걸을 때 측정되었다. 연구결과, 평지 걷기에서는 대조군과 실험군 사이에 통계학적으로 유의한 차이가 없었다. 계단 오르기에서 하이힐을 신었을 때 앞정강근(p.05)과 장딴지근(p.001)에서 실험군에 비해 대조군에서 통계학적으로 유의하게 근 활성화가 증가하였다. 계단 내려오기에서 맨발일 때 척추세움근(p.05)에서 대조군에 비해 실험군에서 통계학적으로 유의하게 근 활성화가 증가하였다. 계단 내려오기에서 하이힐을 착용했을 때 앞정강근(p.01)과 장딴지근(p.05)에서 실험군에 비해 대조군에서 통계학적으로 유의하게 근 활성화가 증가하였다. 본 연구의 결과를 통해 하이힐을 처음 신는 경우가 하이힐을 1년 동안 신은 경우보다 보행 시 하지 근 활성화에 영향을 미친다는 것을 알 수 있었다.

Balance and antecipatory postural adjustments in elderly fallers: effects of kinesiotherapy and virtual rehabilitation

Aging causes a number of changes in motor control of the individual and consequently in postural adjustments. Objective: To evaluate the balance and anticipatory postural adjustments of the agonist muscles and the ankle joint antagonists and compare the effect of rehabilitation virtual and kinesiotherapy in the elderly. Methods: Twenty four elderly participated of this study divided into two groups. 12 participants and the kinesiotherapy group by 12 participants composed the virtual rehabilitation group, equally. The treatment protocol was conducted for six weeks. Virtual rehabilitation group used Xbox 360 with kinect and Your Shape Fitness Evolved game. In the kinesiotherapy group the same protocol exercises were performed. Results: The results indicated a statistically significant difference between pre and post intervention phases in Berg Balance Scale in both groups. There was decreased activation of tibialis anterior muscle in the right functional range of task after interventions, and increased lateral gastrocnemius muscle activation rights in the trunk flexion after training. No differences were observed in muscle activation between the two types of intervention. Conclusion: Protocols with therapeutic exercise and virtual rehabilitation were effective in improving balance and functional capacity of fallers, with no differences between the two types of intervention

Effect of Forefoot Strike on Lower Extremity Muscle Activity and Knee Joint Angle During Cutting in Female Team Handball Players.

BackgroundThe purpose of this study is to examine the effects of different strike forms, during cutting, on knee joint angle and lower limb muscle activity.MethodsSurface electromyography was used to measure muscle activity in individuals performing cutting manoeuvres involving either rearfoot strikes (RFS) or forefoot strikes (FFS). Three-dimensional motion analysis was used to calculate changes in knee angles, during cutting, and to determine the relationship between muscle activity and knee joint angle. Force plates were synchronized with electromyography measurements to compare muscle activity immediately before and after foot strike.ResultsThe valgus angle tends to be smaller during FFS cutting than during RFS cutting. Just prior to ground contact, biceps femoris, semitendinosus, and lateral head of the gastrocnemius muscle activities were significantly greater during FFS cutting than during RFS cutting; tibialis anterior muscle activity was greater during RFS cutting. Immediately after ground contact, biceps femoris and lateral head of the gastrocnemius muscle activities were significantly greater during FFS cutting than during RFS cutting; tibialis anterior muscle activity was significantly lower during FFS cutting.ConclusionsThe results of the present study suggest that the hamstrings demonstrate greater activity, immediately after foot strike, during FFS cutting than during RFS cutting. Thus, FFS cutting may involve a lower risk of anterior cruciate ligament injury than does RFS cutting.

Corticomuscular coherence variation throughout the gait cycle during overground walking and ramp ascent: A preliminary investigation.

Recent designs of neural-machine interfaces (NMIs) incorporating electroencephalography (EEG) or electromyography (EMG) have been used in lower limb assistive devices. While the results of previous studies have shown promise, a NMI which takes advantage of early movement-related EEG activity preceding movement onset, as well as the improved signal-to-noise ratio of EMG, could prove to be more accurate and responsive than current NMI designs based solely on EEG or EMG. Previous studies have demonstrated that the activity of the sensorimotor cortex is coupled to the firing rate of motor units in lower limb muscles during voluntary contraction. However, the exploration of corticomuscular coherence during locomotive tasks has been limited. In this study, coupling between the motor cortex and right tibialis anterior muscle activity was preliminarily investigated during self-paced over-ground walking and ramp ascent. EEG at the motor cortex and surface EMG from the tibialis anterior were collected from one able-bodied subject. Coherence between the two signals was computed and studied across gait cycles. The EEG activity led the EMG activity in the low gamma band in swing phase of level ground walking and in stance phase of ramp ascent. These results may inform the future design of EEG-EMG multimodal NMIs for lower limb devices that assist locomotion of people with physical disabilities.

Tibial impacts and muscle activation during walking, jogging and running when performed overground, and on motorised and non-motorised treadmills

PurposeTo examine tibial acceleration and muscle activation during overground (OG), motorised treadmill (MT) and non-motorised treadmill conditions (NMT) when walking, jogging and running at matched velocities. MethodsAn accelerometer recorded acceleration at the mid-tibia and surface EMG electrodes recorded rectus femoris (RF), semitendinosus (ST), tibialis anterior (TA) and soleus (SL) muscle activation during OG, MT and NMT locomotion whilst walking, jogging and running. ResultsThe NMT produced large reductions in tibial acceleration when compared with OG and MT conditions across walking, jogging and running conditions. RF EMG was small-moderately higher in the NMT condition when compared with the OG and MT conditions across walking, jogging and running conditions. ST EMG showed large and very large increases in the NMT when compared to OG and MT conditions during walking whilst SL EMG found large increases on the NMT when compared to OG and MT conditions during running. The NMT condition generated very large increases in step frequency when compared to OG and MT conditions during walking, with large and very large decreases during jogging and very large decreases during running. ConclusionsThe NMT generates large reductions in tibial acceleration, moderate to very large increases in muscular activation and large to very large decreases in cycle time when compared to OG and MT locomotion. Whilst this may decrease the osteogenic potential of NMT locomotion, there may be uses for NMTs during rehabilitation for lower limb injuries.

Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners

Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strike, tibial and head impact accelerations, and tibialis anterior (TA), peroneus longus (PL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscle activity were registered. Only 68% of the runners adopted a non-rearfoot strike pattern during BF. Running BF led to a reduction of TA activity as well as to an increase of GL and GM activity compared to BRS and SH. Furthermore, BRS increased tibial peak acceleration, tibial magnitude and tibial acceleration rate compared to SH and BF. In conclusion, 32% of our runners showed a rearfoot strike pattern at the first attempts at running barefoot, which corresponds to a running style (BRS) that led to increased muscle activation and impact accelerations and thereby to a potentially higher risk of injury compared to running shod.

The Relationship Between Dolphin Kick Movement And Underwater EMG Of Lower Leg Muscles In Competitive Swimmers

Improvement in swimming performance is not only associated with stroke technique but also with the gliding movement during the start and turn phases. The underwater dolphin kick movement during the start and turn phases is important for improving total race time in modern swimming. PURPOSE: The study was designed to analyze the findings of underwater electromyography of lower limb muscles during the underwater dolphin kick movement in competitive collegiate swimmers. METHODS: Six healthy male collegiate swimmers volunteered to participate in this study. The subjects performed underwater gliding movement at maximum speed after pushing off from the start wall. In addition, three types of underwater dolphin kick movement [Control (C): maximum effort kick; Build-up (BU): small-to-large kick; and Dynamic (D): large kick) were performed with maximum effort. The subjects were monitored through an underwater video camera with a sampling frequency of 60 Hz in the sagittal plane to measure the angular displacement of their different joints. A wireless electromyography system (Biolog DL-5000, S&ME, Japan) was used to collect the muscle activities from the vastus lateralis, hamstrings, tibialis anterior, and gastrocnemius. Speed Meter (Vine Co., Japan) was used to measure swimming speed, and a motion analysis system (Frame-DIAS4; DKH, Japan) was used to digitize body landmarks. RESULTS: Among the underwater dolphin kick movement types, the BU kick was the fastest (BU: 1.67 m/s; C: 1.65 m/s; and D: 1.65 m/s). The rectified EMG findings showed that gastrocnemius and hamstrings muscle activities of elite swimmers were higher than non-elite swimmers during these movements. However, elite swimmers had no muscle activity in the tibialis anterior. CONCLUSIONS: The present study results suggested that the angular displacement of the knee joints gradually increases during underwater dolphin kick movement. In addition, the muscle activity of the hamstrings and gastrocnemius increase during underwater dolphin kick movement. However, the muscle activity of tibialis anterior was inhibited during these movements. Our results also suggested that swimmers experienced a large propulsion force and a small resistance force with the help of these movements.