The Impact of ACTN3 Gene Polymorphisms on Susceptibility to Exercise-Induced Muscle Damage and Changes in Running Economy Following Downhill Running.

This study aimed to investigate if ACTN3 gene polymorphism impacts the susceptibility to exercise-induced muscle damage (EIMD) and changes in running economy (RE) following downhill running. Thirty-five healthy men were allocated to the two groups based on their gene variants: RR and X allele carriers. Neuromuscular function [knee extensor isometric peak torque (IPT), rate of torque development (RTD), and countermovement, and squat jump height], indirect markers of EIMD [muscle soreness, mid-thigh circumference, knee joint range of motion, and serum creatine kinase (CK) activity], and RE (oxygen uptake, minute ventilation, blood lactate concentration, and perceived exertion) for 5-min of running at a speed equivalent to 80% of individual maximal oxygen uptake speed were assessed before, immediately after, and 1-4 days after a 30-min downhill run (-15%).

A single bout of downhill running attenuates subsequent level running-induced fatigue.

Fatigue can be defined as exercise-induced strength loss. During running, fatigue can be partially explained by repetitive low-intensity eccentric contractions-induced muscle damage (EIMD). Previous studies showed that a bout of downhill running (DR) attenuated subsequent EIMD.

Co-contraction of the core muscles during Pilates exercise on the Wunda Chair.

Background: The co-contraction of the core muscles has been reported as the key mechanism towards spinal stability. Classic Pilates exercises aimed at these muscles are known to improve the stability and strength of the trunk without damaging the deep structures of the spine.

Objective: To evaluate the co-contraction of the mobilizing (rectus abdominis; longissimus) and stabilizing (multifidus; internal oblique) trunk muscles during Pilates exercises - going up front, mountain climber, and swan.

Rate of force development and muscle activation of trunk muscles in women with and without low back pain: A case-control study.

Objective: To evaluate the rate of force development (RFD) and the rate of electromyography rise (RER) of global and local trunk muscles in women with and without low back pain.

Design: Cross-sectional study.

Setting: Laboratory setting.

Discriminant analysis of neuromuscular variables in chronic low back pain.

Background: Investigation and discrimination of neuromuscular variables related to the complex aetiology of low back pain could contribute to clarifying the factors associated with symptoms.

Objective: Analysing the discriminative power of neuromuscular variables in low back pain.

Methods: This study compared muscle endurance, proprioception and isometric trunk assessments between women with low back pain (LBP, n=14) and a control group (CG, n=14).

Motor readiness and joint torque production in lower limbs of older women fallers and non-fallers.

This study aimed to evaluate the motor response time and ability to develop joint torque at the knee and ankle in older women with and without a history of falls, in addition to investigating the effect of aging on these capacities. We assessed 18 young females, 21 older female fallers and 22 older female non-fallers. The peak torque, rate of torque development, rate of electromyography (EMG) rise, reaction time, premotor time and motor time were obtained through a dynamometric assessment and simultaneous electromyography.

Back extensor muscle fatigue at submaximal workloads assessed using frequency banding of the electromyographic signal.

Background: Changes in the mean or median frequency of the electromyographic (EMG) power spectrum are often used to assess skeletal muscle fatigue. A more global analysis of the spectral changes using frequency banding may provide a more sensitive measure of fatigue than changes in mean or median frequency. So, the aim of the present study was to characterize changes in different power spectrum frequency bands and compare these with changes in median frequency.

Effect of load level on the emg spectra of longissimus thoracis muscle during isometric fatiguing contractions.

The present study analyzed the effect of different magnitudes of isometric contraction of longissimus thoracis muscle until fatigue by means power spectra analysis. Eight healthy male subjects volunteered for this study The electromyography signals were sampled at 1 kHz using surface electrodes placed bilaterally over the longissimus thoracis muscle at the level L1. The isometric contraction was made at 30% and 60% of isometric maximal voluntary contraction (MVC) randomly in the MA ISOSTATION 2001 with the trunk at 45 degrees of flexion.