The initial effects of a sustained glenohumeral postero-lateral glide during elevation on shoulder muscle activity: A repeated measures study on asymptomatic shoulders

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.

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Quantifying scapula orientation and its influence on maximal hand force capability and shoulder muscle activity

Clinical Biomechanics ◽

10.1016/j.clinbiomech.2009.09.008 ◽

2010 ◽

Vol 25 (1) ◽

pp. 29-36 ◽

Cited By ~ 12

Author(s):

Bryan R. Picco ◽

Steven L. Fischer ◽

Clark R. Dickerson

Keyword(s):

Muscle Activity ◽

Shoulder Muscle ◽

Hand Force

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Changes in shoulder muscle activity pattern on surface electromyography after breast cancer surgery

Journal of Surgical Oncology ◽

10.1002/jso.24800 ◽

2017 ◽

Vol 117 (2) ◽

pp. 116-123 ◽

Cited By ~ 4

Author(s):

Eun Joo Yang ◽

YoungOk Kwon

Keyword(s):

Breast Cancer ◽

Muscle Activity ◽

Activity Pattern ◽

Surface Electromyography ◽

Cancer Surgery ◽

Breast Cancer Surgery ◽

Shoulder Muscle

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Motor learning and transfer: from feedback to feedforward control

10.1101/845933 ◽

2019 ◽

Author(s):

Rodrigo S. Maeda ◽

Paul L. Gribble ◽

J. Andrew Pruszynski

Keyword(s):

Motor Learning ◽

Muscle Activity ◽

Shoulder Joint ◽

Stretch Reflex ◽

Feedforward Control ◽

Motor Task ◽

Joint Torques ◽

Motor Commands ◽

Shoulder Muscle ◽

Long Latency

AbstractPrevious work has demonstrated that when learning a new motor task, the nervous system modifies feedforward (ie. voluntary) motor commands and that such learning transfers to fast feedback (ie. reflex) responses evoked by mechanical perturbations. Here we show the inverse, that learning new feedback responses transfers to feedforward motor commands. Sixty human participants (34 females) used a robotic exoskeleton and either 1) received short duration mechanical perturbations (20 ms) that created pure elbow rotation or 2) generated self-initiated pure elbow rotations. They did so with the shoulder joint free to rotate (normal arm dynamics) or locked (altered arm dynamics) by the robotic manipulandum. With the shoulder unlocked, the perturbation evoked clear shoulder muscle activity in the long-latency stretch reflex epoch (50-100ms post-perturbation), as required for countering the imposed joint torques, but little muscle activity thereafter in the so-called voluntary response. After locking the shoulder joint, which alters the required joint torques to counter pure elbow rotation, we found a reliable reduction in the long-latency stretch reflex over many trials. This reduction transferred to feedforward control as we observed 1) a reduction in shoulder muscle activity during self-initiated pure elbow rotation trials and 2) kinematic errors (ie. aftereffects) in the direction predicted when failing to compensate for normal arm dynamics, even though participants never practiced self-initiated movements with the shoulder locked. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

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The Differences of Shoulder Muscle Activity Onset Time according to Body Tilting Angle in Push-up Exercise

Journal of the Korean Society of Physical Medicine ◽

10.13066/kspm.2015.10.2.55 ◽

2015 ◽

Vol 10 (2) ◽

pp. 55-61 ◽

Cited By ~ 5

Author(s):

Yong-Ho Cho ◽

Sung-Ok Kim ◽

Jin-Ho Choi

Keyword(s):

Muscle Activity ◽

Onset Time ◽

Shoulder Muscle ◽

Tilting Angle ◽

Activity Onset ◽

Push Up

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Muscle Activity during Dryland Swimming while Wearing a Triathlon Wetsuit

International Journal of Kinesiology and Sports Science ◽

10.7575/aiac.ijkss.v.6n.1p.7 ◽

2018 ◽

Vol 6 (1) ◽

pp. 7 ◽

Cited By ~ 1

Author(s):

Ciro Agnelli ◽

John A. Mercer

Keyword(s):

Root Mean Square ◽

Muscle Activity ◽

Swimming Performance ◽

Stroke Rate ◽

Mean Square ◽

Long Distance ◽

Dry Land ◽

Shoulder Muscle ◽

Anterior Deltoid ◽

Paired T Test

Background: Triathletes typically wear a wetsuit during the swim portion of an event, but it is not clear if muscle activity is influenced by wearing a wetsuit. Purpose: To investigate if shoulder muscle activity was influenced by wearing a full-sleeve wetsuit vs. no wetsuit during dryland swimming. Methods: Participants (n=10 males; 179.1±13.2 cm; 91.2±7.25 kg; 45.6±10.5 years) completed two dry land swimming conditions on a swim ergometer: No Wetsuit (NW) and with Wetsuit (W). Electromyography (EMG) of four upper extremity muscles was recorded (Noraxon telemetry EMG, 500 Hz) during each condition: Trapezius (TRAP), Triceps (TRI), Anterior Deltoid (AD) and Posterior Deltoid (PD). Each condition lasted 90 seconds with data collected during the last 60 seconds. Resistance setting was self-selected and remained constant for both conditions. Stroke rate was controlled at 60 strokes per minute by having participants match a metronome. Average (AVG) and Root Mean Square (RMS) EMG were calculated over 45 seconds and each were compared between conditions using a paired t-test (α=0.05) for each muscle. Results: PD and AD AVG and RMS EMG were each greater (on average 40.0% and 66.8% greater, respectively) during W vs. NW (p<0.05) while neither TRAP nor TRI AVG or RMS EMG were different between conditions (p>0.05). Conclusion: The greater PD and AD muscle activity while wearing a wetsuit might affect swimming performance and /or stroke technique on long distance event.

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