title: Differences in the log-transformed electromyographic-force relationships of the plantar flexors between high- and moderate-activated subjects.
abstract: The present study examined the log-transformed electromyographic amplitude (EMG) versus force relationships for the medial gastrocnemius (MG) and soleus (SOL) in high- and moderate-activated subjects. Twenty-five (age=21±2 year; mass=62±12 kg) participants performed six submaximal contractions (30-90% maximal voluntary contraction [MVC]) with the interpolated twitch technique (ITT) performed at 90% MVC to calculate percent voluntary activation (% VA). Sixteen participants with>90% VA at 90% MVC were categorized high-activated group; the remaining nine were the moderate-activated group. Linear regression models were fit to the log-transformed EMG-force relationships. The slope (b value) and the antilog of the Y-intercept (a value) were calculated. The b values from the MG EMG-force relationships were higher (P<0.05) for the high-activated group (1.27±0.13) than the moderate-activated group (0.88±0.06). The a values and p-p M-wave amplitude values (collapsed across twitches [superimposed and potentiated]) were larger (P<0.05) for the MG (1.17±0.40 and 8.98±0.46 mV) than the SOL (0.24±0.07 and 4.48±0.20 mV) when collapsed across groups. The b value from the log-transformed EMG-force relationships is an attractive model to determine if a subject has the ability to achieve high activation of their MG without muscle or nerve stimulation.
authors: Department of Health, Sport and Exercise Sciences, Biomechanics Laboratory, University of Kansas, Lawrence, KS, USA.
authors: Trent J
authors: TJ
authors: Herda
authors: Ashley A
authors: AA
authors: Walter
authors: Pablo B
authors: PB
authors: Costa
authors: Eric D
authors: ED
authors: Ryan
authors: Jeffrey R
authors: JR
authors: Stout
authors: Joel T
authors: JT
authors: Cramer
mesh_terms: D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D016014:Linear Models; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult