Estimating the tendency of motor unit recruitment during steady-hold and rapid contractions using surface EMG and Turns-amplitude analysis.

Li-Ling Pan, Chung-Huang Yu, Mei-Wun Tsai, Shun-Hwa Wei, Li-Wei Chou

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Article in European journal of applied physiology, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 authors at 2 institutions in 1 country.

Li-Ling PanDepartment of Physical Therapy and Assistive Technology, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan.

Chung-Huang YuDepartment of Physical Therapy and Assistive Technology, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan.

Mei-Wun TsaiDepartment of Physical Therapy and Assistive Technology, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan.

Shun-Hwa WeiDepartment of Physical Therapy and Assistive Technology, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan.

Li-Wei ChouDepartment of Physical Therapy and Assistive Technology, National Yang-Ming University, No.155, Sec.2, Li-Nong Street, Taipei, 112, Taiwan. lwchou@ym.edu.tw.

National Yang Ming University Hospital · TWNational Yang Ming Chiao Tung University · TW

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6 · The paper itself

Abstract

purposeThe purpose of this study was to investigate changes in the interference pattern in surface electromyography (EMG), and its relationship with the tendency of motor unit (MU) recruitment during steady-hold and rapid muscle contractions.

methodsFifteen healthy adults (eight females and seven males, 22.6 ± 1.5 years old) performed steady-hold and rapid isometric contractions of the bicep brachii, adductor pollicis, and tibialis anterior muscles at various force levels. Surface EMG recordings were analyzed using Turns-Amplitude Analysis (TAA).

resultsDuring steady-hold contractions, the number of turns per second (T/s) increased exponentially with force during submaximal contractions, and plateaued after force levels of 66, 70 and 57 % MVC for the tibialis anterior, bicep brachii and adductor pollicis muscles, respectively. These force levels were proximate to the maximal recruitment threshold (MaxRT) reported previously. The slopes of the T/s-force relationships before the MaxRT were significantly greater than the slopes after the MaxRT for all three muscles tested. During rapid contraction, the slopes of the T/s-force relationships were significantly lower than the slopes of the steady-hold contraction at 20-40 % MVC in all three muscles, and for 40-60 % MVC in TA muscles.

conclusionsOur results suggested that the changes in the number of turns in surface EMG with respect to muscle force can be used to estimate the force levels at which the majority of the MUs to be recruited, and completion of MU recruitment was observed at lower force levels during rapid muscle contraction.

Indexed as

ElectromyographyFemaleHumansIsometric ContractionMaleMotor NeuronsMuscle ContractionMuscle, SkeletalRecruitment, NeurophysiologicalYoung AdultMaximal recruitment thresholdMotor unitRapid contractionSteady-holdSurface electromyographyTurns-Amplitude Analysis

Identifiers

PMID26202486

DOI10.1007/s00421-015-3223-8

OpenAlexW1029853738

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