Reproducibility and changes in twitch properties associated with age and resistance training in young and elderly women

Abstract

We compared knee extensor twitch contractile properties (TP) between nine young women (YW, 20-30 years) and 10 elderly women (63-78 years) and examined changes associated with resistance training in addition to measurement reproducibility. Data were obtained on two occasions 3 weeks apart after which subjects performed bilateral leg extension and bilateral leg curl exercises 3 days/week for 10 weeks. TP demonstrated moderate to good reproducibility in both age groups with Pearson's r and the intra-class correlation coefficient ranging from 0.67 to 0.85 (P<0.05) and the technical error of the measurement ranging from 4.2% to 7.8%. Pre-training, peak twitch torque, rate of torque development, and the rate of relaxation were 24-32% greater for the YW than EW (P<0.05). Time to peak torque, half-relaxation time, and contraction duration were not significantly different between age groups. Post-training, changes of 2.6-6.1% were observed in TP; however, these changes were not significant in either group. These data suggest the presence of an age-associated slowing in the rate of muscle contraction. Furthermore, the lack of change in TP in both groups suggests resistance training failed to alter contractile function. However, these findings are discussed in relation to measurement reproducibility and the meaningfulness of the data obtained.

Direct and indirect measurement of neuromuscular fatigue in Canadian football players

“…In addition, percent change from T Base was calculated and a one-sample t test against zero was conducted to provide additional assurance of the accuracy of baseline data (Table 1). In line with previous literature (Cannon et al 2008), all direct measures showed moderate to good reproducibility, with ICCs ranging from 0.67 to 0.99 and TEM ranging from 6.3% to 13.2%. Good reliability was also shown for the 3 CMJ variables (ICC, r = 0.77 to 0.98; TEM = 5.1% to 5.7%).…”

Comparing the reliability of voluntary and evoked muscle actions

“…Although previous studies have reported the reliability of evoked and voluntary muscle actions separately (Place et al, 2007;Cannon et al, 2008), none have specifically compared the reliability of voluntary versus evoked muscle actions. Our study indicated that, except for TRTD V , voluntary and evoked measures of neuromuscular function are similarly consistent.…”

Cold‐water immersion decreases cerebral oxygenation but improves recovery after intermittent‐sprint exercise in the heat

“…Force outputs were corrected for gravitation effects and torque values were quantified in relation to lever arm length during analyses using the methods of Cannon et al. ().…”

“…The MVC protocol involved 20 ¥ 5 s isometric efforts completed using a work-to-rest ratio of 1:1. Force outputs were corrected for gravitation effects and torque values were quantified in relation to lever arm length during analyses using the methods of Cannon et al (2008).…”