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Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men.
Eur J Appl Physiol. 2013 Sep; 113(9):2391-9.EJ

Abstract

PURPOSE

The purpose of this study was to investigate the effects of a fatigue-inducing bout of submaximal, intermittent isometric contractions on the electromechanical delay (EMD) of the leg extensors and flexors in young and old men.

METHODS

Twenty young (mean ± SD: age = 25 ± 2.8 years) and sixteen old (age = 70.8 ± 3.8) recreationally active men performed maximal voluntary contractions (MVCs) followed by a fatigue-inducing protocol consisting of intermittent isometric contractions of the leg extensors or flexors using a 0.6 duty cycle (6 s contraction, 4 s relaxation) at 60 % of MVC until volitional fatigue. MVCs were again performed at 0, 7, 15, and 30 min post fatigue. A three-way mixed factorial ANOVA was used to analyze the EMD data.

RESULTS

There was a two-way muscle × time interaction (P = 0.039) where the EMD of the leg flexors was greater (P = 0.001-0.034) compared with baseline at all post fatigue time periods, but was only greater at immediately post fatigue for the extensors (P = 0.001). A significant two-way interaction for muscle × age (P = 0.009) revealed that the EMD was greater (P = 0.003) for the extensors for the old compared with the young men, but not different for the flexors (P = 0.506).

CONCLUSIONS

These findings showed differential fatigue-induced EMD recovery patterns between the leg extensors and flexors with the flexors being slower to recover and also that age-related increases of EMD are muscle group specific. The sustained increased EMD of the flexors during recovery may have important injury and performance implications in a variety of populations and settings.

Authors+Show Affiliations

Applied Musculoskeletal and Human Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, Stillwater, OK 74078, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

23771530

Citation

Conchola, E C., et al. "Effects of Neuromuscular Fatigue On the Electromechanical Delay of the Leg Extensors and Flexors in Young and Old Men." European Journal of Applied Physiology, vol. 113, no. 9, 2013, pp. 2391-9.
Conchola EC, Thompson BJ, Smith DB. Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men. Eur J Appl Physiol. 2013;113(9):2391-9.
Conchola, E. C., Thompson, B. J., & Smith, D. B. (2013). Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men. European Journal of Applied Physiology, 113(9), 2391-9. https://doi.org/10.1007/s00421-013-2675-y
Conchola EC, Thompson BJ, Smith DB. Effects of Neuromuscular Fatigue On the Electromechanical Delay of the Leg Extensors and Flexors in Young and Old Men. Eur J Appl Physiol. 2013;113(9):2391-9. PubMed PMID: 23771530.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men. AU - Conchola,E C, AU - Thompson,B J, AU - Smith,D B, Y1 - 2013/06/15/ PY - 2013/02/26/received PY - 2013/05/31/accepted PY - 2013/6/18/entrez PY - 2013/6/19/pubmed PY - 2014/5/20/medline SP - 2391 EP - 9 JF - European journal of applied physiology JO - Eur J Appl Physiol VL - 113 IS - 9 N2 - PURPOSE: The purpose of this study was to investigate the effects of a fatigue-inducing bout of submaximal, intermittent isometric contractions on the electromechanical delay (EMD) of the leg extensors and flexors in young and old men. METHODS: Twenty young (mean ± SD: age = 25 ± 2.8 years) and sixteen old (age = 70.8 ± 3.8) recreationally active men performed maximal voluntary contractions (MVCs) followed by a fatigue-inducing protocol consisting of intermittent isometric contractions of the leg extensors or flexors using a 0.6 duty cycle (6 s contraction, 4 s relaxation) at 60 % of MVC until volitional fatigue. MVCs were again performed at 0, 7, 15, and 30 min post fatigue. A three-way mixed factorial ANOVA was used to analyze the EMD data. RESULTS: There was a two-way muscle × time interaction (P = 0.039) where the EMD of the leg flexors was greater (P = 0.001-0.034) compared with baseline at all post fatigue time periods, but was only greater at immediately post fatigue for the extensors (P = 0.001). A significant two-way interaction for muscle × age (P = 0.009) revealed that the EMD was greater (P = 0.003) for the extensors for the old compared with the young men, but not different for the flexors (P = 0.506). CONCLUSIONS: These findings showed differential fatigue-induced EMD recovery patterns between the leg extensors and flexors with the flexors being slower to recover and also that age-related increases of EMD are muscle group specific. The sustained increased EMD of the flexors during recovery may have important injury and performance implications in a variety of populations and settings. SN - 1439-6327 UR - https://www.unboundmedicine.com/medline/citation/23771530/Effects_of_neuromuscular_fatigue_on_the_electromechanical_delay_of_the_leg_extensors_and_flexors_in_young_and_old_men_ L2 - https://dx.doi.org/10.1007/s00421-013-2675-y DB - PRIME DP - Unbound Medicine ER -