scholarly journals Perceptibility of Large and Sequential Changes in Somatosensory Information during Leaning Forward and Backward When Standing

2003 ◽  
Vol 96 (2) ◽  
pp. 549-577 ◽  
Author(s):  
Hitoshi Asai ◽  
Katsuo Fujiwara
Keyword(s):  
Individual Differences ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Cooling Condition ◽  
Maximum Pressure ◽  
Abductor Hallucis ◽  
Foot Pressure ◽  
Somatosensory Information ◽  
Pressure Sensation

11 healthy young men served as subjects in two experiments on perceptibility of (1) large changes in foot pressure and muscle activity induced by body leaning and (2) sequential changes in pressure at the first toe and the head of the first metatarsalis when leaning forward. The effects of reduced sensitivity on that perceptibility were also studied by repeating the experiments while cooling localized plantar areas of the sole (the head of the first metatarsalis, the first toe, and the heel). Under the normal (noncooled) condition, all subjects accurately perceived maximum pressure at the head of the first metatarsalis, but most subjects misperceived the second large increase in pressure at the first toe and in muscle activity as the first large increase. Under the cooling condition, localized cooling did not affect the perceptibility of maximum pressure at the head of the first metatarsalis or the activity in the tibialis anterior, but the perceptibility of pressure at the first toe and activity of the abductor hallucis were reduced. There were individual differences in perceptibility of activity of the rectus femoris when the heel was cooled. Perceptibility of sequential changes in the pressure was affected differently by the localized cooling of each region. Given these findings, we discussed the role and interrelatedness of pressure sensation in perceiving large and sequential changes in somatosensory information while standing and leaning forward and backward.

Lower-Extremity Muscle Activity During Aquatic and Land Treadmill Running at the Same Speeds

2014 ◽  
Vol 23 (2) ◽  
pp. 107-122 ◽  
Author(s):  
W. Matthew Silvers ◽  
Eadric Bressel ◽  
D. Clark Dickin ◽  
Garry Killgore ◽  
Dennis G. Dolny
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Swing Phase ◽  
Treadmill Running ◽  
Vastus Medialis ◽  
Lower Extremity Muscle

Context:Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running.Objectives:The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds.Design:Exploratory, quasi-experimental, crossover design.Setting:Athletic training facility.Participants:12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation.Intervention:All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris.Main Outcome Measures:For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment–speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT.Results:Compared with TM, ATM elicited significantly reduced %MVC (−44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (−26.9%) and tACT (−40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6−15.2%) and tACT (+12.7−17.0%) and rectus femoris %MVC (12.1−26.6%; swing phase).Conclusion:No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water.

Comparison of Estimated and Measured Muscle Activity During Inclined Walking

2016 ◽  
Vol 32 (2) ◽  
pp. 150-159 ◽  
Author(s):  
Nathalie Alexander ◽  
Hermann Schwameder
Keyword(s):  
Trend Analysis ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Vastus Lateralis ◽  
A Priori ◽  
Correlation Coefficients ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Musculoskeletal Models ◽  
Downhill Walking

While inclined walking is a frequent daily activity, muscle forces during this activity have rarely been examined. Musculoskeletal models are commonly used to estimate internal forces in healthy populations, but these require a priori validation. The aim of this study was to compare estimated muscle activity using a musculoskeletal model with measured EMG data during inclined walking. Ten healthy male participants walked at different inclinations of 0°, ± 6°, ± 12°, and ± 18° on a ramp equipped with 2 force plates. Kinematics, kinetics, and muscle activity of the musculus (m.) biceps femoris, m. rectus femoris, m. vastus lateralis, m. tibialis anterior, and m. gastrocnemius lateralis were recorded. Agreement between estimated and measured muscle activity was determined via correlation coefficients, mean absolute errors, and trend analysis. Correlation coefficients between estimated and measured muscle activity for approximately 69% of the conditions were above 0.7. Mean absolute errors were rather high with only approximately 38% being ≤ 30%. Trend analysis revealed similar estimated and measured muscle activities for all muscles and tasks (uphill and downhill walking), except m. tibialis anterior during uphill walking. This model can be used for further analysis in similar groups of participants.

Contralateral Movement and Extensor Force Generation Alter Flexion Phase Muscle Coordination in Pedaling

2000 ◽  
Vol 83 (6) ◽  
pp. 3351-3365 ◽  
Author(s):  
Lena H. Ting ◽  
Steven A. Kautz ◽  
David A. Brown ◽  
Felix E. Zajac
Keyword(s):  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
The Body ◽  
Force Generation ◽  
Mechanical Transmission ◽  
Electromyographic Activity ◽  
Neural Pathways ◽  
Control Mechanisms ◽  
Muscle Coordination

The importance of bilateral sensorimotor signals in coordination of locomotion has been demonstrated in animals but is difficult to ascertain in humans due to confounding effects of mechanical transmission of forces between the legs (i.e., mechanical interleg coupling). In a previous pedaling study, by eliminating mechanical interleg coupling, we showed that muscle coordination of a unipedal task can be shaped by interlimb sensorimotor pathways. Interlimb neural pathways were shown to alter pedaling coordination as subjects pedaling unilaterally exhibited increased flexion-phase muscle activity compared with bilateral pedaling even though the task mechanics performed by the pedaling leg(s) in the unilateral and bilateral pedaling tasks were identical. To further examine the relationship between contralateral sensorimotor state and ipsilateral flexion-phase muscle coordination during pedaling, subjects in this study pedaled with one leg while the contralateral leg either generated an extensor force or relaxed as a servomotor either held that leg stationary or moved it in antiphase with the pedaling leg. In the presence of contralateral extensor force generation, muscle activity in the pedaling leg during limb flexion was reduced. Integrated electromyographic activity of the pedaling-leg hamstring muscles (biceps femoris and semimembranosus) during flexion decreased by 25–30%, regardless of either the amplitude of force generated by the nonpedaling leg or whether the leg was stationary or moving. In contrast, rectus femoris and tibialis anterior activity during flexion decreased only when the contralateral leg generated high rhythmic force concomitant with leg movement. The results are consistent with a contralateral feedforward mechanism triggering flexion-phase hamstrings activity and a contralateral feedback mechanism modulating rectus femoris and tibialis anterior activity during flexion. Because only muscles that contribute to flexion as a secondary function were observed, it is impossible to know whether the modulatory effect also acts on primary, unifunctional, limb flexors or is specific to multifunctional muscles contributing to flexion. The influence of contralateral extensor-phase sensorimotor signals on ipsilateral flexion may reflect bilateral coupling of gain control mechanisms. More generally, these interlimb neural mechanisms may coordinate activity between muscles that perform antagonistic functions on opposite sides of the body. Because pedaling and walking share biomechanical and neuronal control features, these mechanisms may be operational in walking as well as pedaling.

Effect of dynamic guidance-tubing short foot gait exercise on muscle activity and navicular movement in people with flexible flatfeet

2020 ◽  
Vol 47 (2) ◽  
pp. 217-226
Author(s):  
Dohee Jung ◽  
Chunghwi Yi ◽  
Woochol Joseph Choi ◽  
Joshua Sung H. You
Keyword(s):  
Pressure Distribution ◽  
Muscle Activity ◽  
Activity Ratio ◽  
Weight Bearing ◽  
Tibialis Posterior ◽  
Abductor Hallucis ◽  
Foot Pressure ◽  
Flat Feet ◽  
Flexor Digitorum Brevis ◽  
Flexor Digitorum

BACKGROUND: Navicular drop is a common plantar deformity which makes the plantar medial longitudinal arch (MLA) collapse and leads to other deformities in lower extremities. Active structures are from intrinsic and extrinsic foot muscle activities such as abductor hallucis (AbdH), tibialis anterior (TA), tibialis posterior, flexor hallucis brevis, flexor digitorum brevis during dynamic situations. As AbdH plays a role as a dynamic elevator of MLA, the importance of AbdH has been emphasized and the proper recruitment of both intrinsic and extrinsic muscle is crucial for stabilization of MLA during dynamic weight bearing condition. Because the short foot (SF) exercise is difficult to perform and tends to activate the intrinsic muscles concentrically rather than a natural coordination of concentric-isometric-eccentric activation, we have developed the guidance-tubing SF gait (GFG) exercise. OBJECTIVE: We investigated the effect of GFG exercise on muscle activity, AbdH:TA activity ratio, MLA angle, and foot pressure distribution during walking compared to SF gait (SFG) exercise. METHODS: Thirty-two subjects with flexible flat feet were divided into two groups and performed SFG exercise with (GFG) and without guidance-tubing (SFG) for seven serial days. RESULTS: AbdH muscle activity significantly increased from foot flat to heel rise in the GFG group (p = 0.006). The AbdH:TA activity ratio significantly increased in both the SFG (p = 0.015) group and GFG group (p = 0.006). MLA angles significantly decreased in both the SFG group (p = 0.001) and GFG group (p = 0.000), and the decrement was significantly higher in the GFG group (p = 0.001). The foot pressure distribution did not show any statistically significant change. CONCLUSIONS: The result of this study provides a clinical implication for training MLA supporter muscles in individuals with flat feet. The overactive muscle must be inhibited first, then facilitation and strengthening are followed respectively.

Neuromuscular Activation During Short-Track Speed Skating in Young Athletes

2016 ◽  
Vol 11 (7) ◽  
pp. 848-854 ◽  
Author(s):  
Sabine Felser ◽  
Martin Behrens ◽  
Susanne Fischer ◽  
Mario Baeumler ◽  
Ralf Salomon ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Time Trial ◽  
Rectus Femoris ◽  
Young Athletes ◽  
Neuromuscular Activation ◽  
Leg Muscles ◽  
Maximum Effort ◽  
The Right

Purpose:To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT.Results:Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.

scholarly journals Temporal Changes in Electromyographic Activity and Gait Ability during Extended Walking in Individuals Post-Stroke: A Pilot Study

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 444
Author(s):  
Kazuki Fujita ◽  
Yasutaka Kobayashi ◽  
Masahito Hitosugi
Keyword(s):  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Temporal Changes ◽  
Neuromuscular Fatigue ◽  
Electromyographic Activity ◽  
Mean Frequency ◽  
Abnormal Gait ◽  
Walking Performance ◽  
Over Time

Abnormal gait, particularly in patients with stroke, causes neuromuscular fatigue. We aimed to clarify temporal changes in gait performance and lower limb muscle activity during extended walking in people with stroke hemiplegia. Twelve adults with stroke and eleven healthy controls performed an extended trial involving 20-min continuous walk at a comfortable speed. The primary outcome was electromyography amplitude during the trial and secondary outcomes were walking performance and the instantaneous mean frequency of electromyography during the trial. Data at 1, 6, 12, and 18 min after initiating walking were compared. Performance during extended walking in people with stroke was maintained over time. The electromyography amplitude decreased in the tibialis anterior during the pre-swing phase and increased in the rectus femoris during the single-support phase over time; these changes were similar on the paretic and nonparetic sides. Instantaneous mean frequency decreased over time on the nonparetic side in the tibialis anterior and on the paretic side in the rectus femoris. Healthy subjects did not show any changes over time. The changes in muscle activity in patients with stroke differed between the paretic and nonparetic sides, muscle type, and gait phase; walking performance was maintained despite being affected by neuromuscular fatigue.

Muscle Activity During Running With Different Body-Weight-Support Mechanisms: Aquatic Environment Versus Body-Weight-Support Treadmill

2014 ◽  
Vol 23 (4) ◽  
pp. 300-306 ◽  
Author(s):  
John A. Mercer ◽  
Bryon C. Applequist ◽  
Kenji Masumoto
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Body Weight Support ◽  
Stride Frequency ◽  
Positive Pressure ◽  
Lower Extremity Muscle ◽  
Weight Support

Background:Body-weight (BW) support during running can be accomplished using deep-water running (DWR; 100% BW support) and a lower-body positive-pressure (LBPP) treadmill.Purpose:To compare lower-extremity muscle activity during DWR and running on an LBPP treadmill at matched stride frequency.Methods:Eight subjects (40 ± 6.5 y, 173 ± 7.2 cm, 66.9 ± 11.7 kg) completed 4 running conditions all at a preferred stride frequency that was determined while running with no support. Two conditions were running on the LBPP treadmill at 60% and 80% of BW, and the other 2 conditions were different DWR styles: high knee (DWR-HK) and cross-country (DWR-CC). Average (AVG) and root-mean-square (RMS) electromyography (rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior) were each compared among conditions (repeated-measures analysis of variance).Results:Results for AVG and RMS variables were identical for statistical tests for each muscle. Rectus femoris electromyography during DWR-HK was lower than that of DWR-CC (P < .05) but not different than either 60% BW or 80% BW (P > .05). Biceps femoris electromyography was less during DWR-HK than DWR-CC (P < .05) but greater during DWR-HK than either BW 60% or BW 80% (P < .05). Neither gastrocnemius nor tibialis anterior electromyography differed between conditions (P > .05).Conclusion:Neither the mechanism of BW support nor style of DWR influenced gastrocnemius or tibialis anterior muscle activity during running at the same stride frequency. However, rectus femoris and biceps femoris muscle activity were influenced by not only the mechanism of BW support but also the style of DWR.

A Neuromuscular and Metabolic Comparison between Forward and Reverse Pedaling

1998 ◽  
Vol 14 (4) ◽  
pp. 401-411 ◽  
Author(s):  
Eadric Bressel ◽  
Gary D. Heise ◽  
Greg Bachman
Keyword(s):  
Oxygen Consumption ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Half Cycle ◽  
Physically Active ◽  
Crank Angle

The purpose of this study was to determine how muscle activity and oxygen consumption are influenced by reverse pedaling (RP) compared to forward pedaling (FP). Seventeen physically active males performed FP and RP at an external workrate of 157 W (80 rpm) while EMG data were collected from five muscles: rectus femoris (RF), biceps femoris (BF), gastrocnemius (GN), tibialis anterior (TA), and vastus medialis (VM). Oxygen consumption (V̇O2 L·min-1) data were collected. On-time durations and EMG amplitudes were quantified for each half-cycle (first 180° and second 180° of crank angle). V̇O2 was similar between pedaling conditions while muscles RF and BF exhibited phasic shifts in response to RP with no amplitude change. VM showed an increase and GN displayed a decrease in EMG amplitude from FP to RP. The phasic shifts in muscle activation seen in RP, particularly in RF and BF, may alter the sequence of the knee extensor–hip extensor joint moments during the first half-cycle of pedaling.

scholarly journals Changes in muscle coactivation during running: a comparison between two techniques, forefoot vs rearfoot

2021 ◽  
Vol 38 (5) ◽  
pp. 332-336
Author(s):  
Daniel Araya ◽  
Juan López ◽  
Germán Villalobos ◽  
Rodrigo Guzmán-Venegas ◽  
Oscar Valencia
Keyword(s):  
Muscle Activity ◽  
Surface Electromyography ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Initial Contact ◽  
Joint Stability ◽  
Paired Data ◽  
Lateral Gastrocnemius

Introduction: Surface electromyography has been a technique used to describe muscle activity during running. However, there is little literature that analyses the behaviour of muscle coactivation in runners, describing the effect between two techniques associated with the initial contact, such as the use of rearfoot (RF) and forefoot (FF). Material and method: The purpose of this study was to compare muscle coactivation levels developed in the lower limb during two running techniques, FF vs RF. Fourteen amateur runners were evaluated (eight men, six women; age= 23.21 ± 3.58 years, mass= 63.89 ± 8.13 kg, height= 1.68 ± 0.08m). Surface electromyography was used to measure muscle activity during both running techniques evaluated on a treadmill, considering the muscle pairs: Rectus femoris- Biceps femoris (RFe-BF), Lateral Gastrocnemius–Tibialis Anterior (LG-TA), and Medial Gastrocnemius - Tibialis Anterior (MG-TA). These were calculated in three windows considering ten running cycles (0-5%, 80-100%, and 0-100%). To compare FF vs RF t-student test for paired data was used. Results: It was observed significant differences in the MG-TA pair (FF= 18.42 ± 11.84% vs RF = 39.05 ± 13.28%, p = 0.0018 during 0-5%, and RFe-BF pair (FF = 42.38 ± 18.11% vs RF = 28.37 ± 17.2%, p = 0.0331) during 80-100% of the race. Conclusion: Our findings show that the behaviour of muscle coactivation is different between FF vs RF techniques if we analyze little windows in the running cycle. This could be associated with an increase in the joint stability between these short intervals, represented in the initial and final regions of the running cycle.

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