-
1.
Effect of tendon vibration during wide-pulse neuromuscular electrical stimulation (NMES) on the decline and recovery of muscle force.
Bochkezanian, V, Newton, RU, Trajano, GS, Vieira, A, Pulverenti, TS, Blazevich, AJ
BMC neurology. 2017;(1):82
Abstract
BACKGROUND Neuromuscular electrical stimulation (NMES) is commonly used to activate skeletal muscles and reverse muscle atrophy in clinical populations. Clinical recommendations for NMES suggest the use of short pulse widths (100-200 μs) and low-to-moderate pulse frequencies (30-50 Hz). However, this type of NMES causes rapid muscle fatigue due to the (non-physiological) high stimulation intensities and non-orderly recruitment of motor units. The use of both wide pulse widths (1000 μs) and tendon vibration might optimize motor unit activation through spinal reflex pathways and thus delay the onset of muscle fatigue, increasing muscle force and mass. Thus, the objective of this study was to examine the acute effects of patellar tendon vibration superimposed onto wide-pulse width (1000 μs) knee extensor electrical stimulation (NMES, 30 Hz) on peak muscle force, total impulse before "muscle fatigue", and the post-exercise recovery of muscle function. METHODS Tendon vibration (Vib), NMES (STIM) or NMES superimposed onto vibration (STIM + Vib) were applied in separate sessions to 16 healthy adults. Total torque-time integral (TTI), maximal voluntary contraction torque (MVIC) and indirect measures of muscle damage were tested before, immediately after, 1 h and 48 h after each stimulus. RESULTS TTI increased (145.0 ± 127.7%) in STIM only for "positive responders" to the tendon vibration (8/16 subjects), but decreased in "negative responders" (-43.5 ± 25.7%). MVIC (-8.7%) and rectus femoris electromyography (RF EMG) (-16.7%) decreased after STIM (group effect) for at least 1 h, but not after STIM + Vib. No changes were detected in indirect markers of muscle damage in any condition. CONCLUSIONS Tendon vibration superimposed onto wide-pulse width NMES increased TTI only in 8 of 16 subjects, but reduced voluntary force loss (fatigue) ubiquitously. Negative responders to tendon vibration may derive greater benefit from wide-pulse width NMES alone.
-
2.
Effect of vitamin A administration on free radicals and lactate levels in individuals exercised to exhaustion.
Patlar, S, Baltaci, AK, Mogulkoc, R
Pakistan journal of pharmaceutical sciences. 2016;(5):1531-1534
Abstract
This study was performed to explore the effect of vitamin A administration on Free Radicals production and antioxidant system activity and lactate levels in individuals exercised to exhaustion The study registered 10 healthy sedentary males their mean age was 22,85±0,26 years. The subjects were orally administrated with 300 mg vitamin A (retinol) for 4 weeks and engaged in strenuous exercise (using the Bruce protocol) once a week. Blood samples were collected from the subjects at four different times, before and after the supplementation and before and after exercise to analyze Malondialdehyde (MDA), Nitric oxide (NO), Glutathione (GSH), Glutathione peroxidase (GSH-Px), Catalase (CAT), Superoxide dismutase (SOD) levels using colorimetric ELISA test kits and plasma lactate levels using an autoanalyzer. Exhaustion exercise leaded to an increase in both MDA, NO, and lactate, and GSH, GSH-Px, CAT and SOD levels compared to resting levels both before and after supplementation (p<0.05). Increased NO levels found in pre-supplementation exhaustion showed a significant decrease after the supplementation of vitamin A (p<0.05), but the other parameters were not changed after vitamin A administration. The results of our study demonstrate that the increase caused by 4-week strenuous exercise in the levels of the free radical NO was offset by vitamin A supplementation. It can be suggested that supplementation of vitamin A at physiological doses has a limited effect on lipid peroxidation caused by strenuous exercise.
-
3.
A Novel Noninvasive Method for Measuring Fatigability of the Quadriceps Muscle in Noncooperating Healthy Subjects.
Poulsen, JB, Rose, MH, Møller, K, Perner, A, Jensen, BR
BioMed research international. 2015;:193493
Abstract
BACKGROUND Critical illness is associated with muscle weakness leading to long-term functional limitations. OBJECTIVES To assess the reliability of a novel method for evaluating fatigability of the quadriceps muscle in noncooperating healthy subjects. METHODS On two occasions, separated by seven days, nonvoluntary isometric contractions (twitch and tetanic) of the quadriceps femoris muscle evoked by transcutaneous electrical muscle stimulation were recorded in twelve healthy adults. For tetanic contractions, the Fatigue Index (ratio of peak torque values) and the slope of the regression line of peak torque values were primary outcome measures. For twitch contractions, maximum peak torque and rise time were calculated. Relative (intraclass correlation, ICC3.1) and absolute (standard error of measurement, SEM) reliability were assessed and minimum detectable change was calculated using a 95% confidence interval (MDC95%). RESULTS The Fatigue Index (ICC3.1, 0.84; MDC95%, 0.12) and the slope of the regression line (ICC3.1, 0.99; MDC95%, 0.03) showed substantial relative and absolute reliability during the first 15 and 30 contractions, respectively. CONCLUSION This method for assessing fatigability of the quadriceps muscle produces reliable results in healthy subjects and may provide valuable data on quantitative changes in muscle working capacity and treatment effects in patients who are incapable of producing voluntary muscle contractions.
-
4.
Repeated bout effect was more expressed in young adult males than in elderly males and boys.
Gorianovas, G, Skurvydas, A, Streckis, V, Brazaitis, M, Kamandulis, S, McHugh, MP
BioMed research international. 2013;:218970
Abstract
This study investigated possible differences using the same stretch-shortening exercise (SSE) protocol on generally accepted monitoring markers (dependent variables: changes in creatine kinase, muscle soreness, and voluntary and electrically evoked torque) in males across three lifespan stages (childhood versus adulthood versus old age). The protocol consisted of 100 intermittent (30 s interval between jumps) drop jumps to determine the repeated bout effect (RBE) (first and second bouts performed at a 2-week interval). The results showed that indirect symptoms of exercise-induced muscle damage after SSE were more expressed in adult males than in boys and elderly males, suggesting that the muscles of boys and elderly males are more resistant to exercise-induced damage than those of adult males. RBE was more pronounced in adult males than in boys and elderly males, suggesting that the muscles of boys and elderly males are less adaptive to exercise-induced muscle damage than those of adult males.
-
5.
Relationship between serum creatine kinase activity following exercise-induced muscle damage and muscle fibre composition.
Magal, M, Dumke, CL, Urbiztondo, ZG, Cavill, MJ, Triplett, NT, Quindry, JC, McBride, JM, Epstein, Y
Journal of sports sciences. 2010;(3):257-66
Abstract
In this study, we examined the relationship between serum creatine kinase activity following exercise-induced muscle damage and muscle fibre composition. Seventeen untrained males volunteered and underwent a .[Vdot]O2max test, Wingate test, and an exercise-induced muscle damage protocol. Muscle soreness and blood samples were recorded before, immediately after, and 24, 48, 72, and 96 h after exercise. Biopsy samples from the vastus lateralis were collected one week after exercise-induced muscle damage and were assessed for muscle fibre composition. There was no significant relationship (P > 0.05) between muscle fibre composition and creatine kinase activity. A significant positive correlation (P < 0.05) was observed between soreness 48 h after exercise and type II and IIb fibres, and a significant negative correlation (P < 0.05) was observed between soreness 48 h after exercise and type I muscle fibres. Significant positive correlations were observed between soreness 48 h after exercise and the fatigue index, relative average power, and relative anaerobic capacity. Our results suggest that creatine kinase activity following exercise-induced muscle damage may not be related to muscle fibre proportions, and higher post-exercise muscular pain may be related to a predominance of type II muscle fibres and higher anaerobic capabilities.
-
6.
Acute passive stretching in a previously fatigued muscle: Electrical and mechanical response during tetanic stimulation.
Esposito, F, Ce, E, Rampichini, S, Veicsteinas, A
Journal of sports sciences. 2009;(12):1347-57
Abstract
The aim of this study was to assess the effects of acute passive stretching on the electrical and mechanical response of a previously fatigued muscle. Eleven participants underwent maximal tetanic stimulations (50 Hz) of the medial gastrocnemius, before and after a fatiguing protocol and after a bout of passive stretching of the fatigued muscle. During contraction, surface electromyography (EMG), mechanomyography (MMG), and force were recorded. The following parameters were calculated: (1) the EMG root mean square (RMS), mean frequency, and fibre conduction velocity; (2) MMG peak-to-peak and RMS; (3) the peak force, contraction time, half-relaxation time, peak rate of force development (dF/dt) and its acceleration (d(2)F/dt(2)). Fatigue reduced peak force by 18% (P < 0.05) and affected the other force, EMG, and MMG parameters. After stretching: (1) all EMG parameters recovered to pre-fatigue values; (2) MMG peak-to-peak remained depressed, while RMS recovered to pre-fatigue values; (3) the peak force, peak rate of force development and its acceleration were further reduced by 22, 18, and 51%, respectively, and half-relaxation time by 40% (P < 0.05). In conclusion, acute passive stretching, when applied to a previously fatigued muscle, further depresses the maximum force-generating capacity. Although stretching does not alter the electrical parameters of the fatigued muscle, it does affect the mechanical behaviour of the muscle-tendon unit.
-
7.
The effect of induced alkalosis and submaximal cycling on neuromuscular response during sustained isometric contraction.
Hunter, AM, De Vito, G, Bolger, C, Mullany, H, Galloway, SD
Journal of sports sciences. 2009;(12):1261-9
Abstract
The aim of this study was to determine if inducing metabolic alkalosis would alter neuromuscular control after 50 min of standardized submaximal cycling. Eight trained male cyclists (mean age 32 years, s = 7; [Vdot]O(2max) 62 ml . kg(-1) x min(-1), s = 8) ingested capsules containing either CaCO(3) (placebo) or NaHCO(3) (0.3 g x kg(-1) body mass) in eight doses over 2 h on two separate occasions, commencing 3 h before exercise. Participants performed three maximal isometric voluntary contractions (MVC) of the knee extensors while determining the central activation ratio by superimposing electrical stimulation both pre-ingestion and post-exercise, followed by a 50-s sustained maximal contraction in which force, EMG amplitude, and muscle fibre conduction velocity were assessed. Plasma pH, blood base excess, and plasma HCO(3) were higher (P < 0.01) during the NaHCO(3) trial. After cycling, muscle fibre conduction velocity was higher (P < 0.05) during the 50-s sustained maximal contraction with NaHCO(3) than with placebo (5.1 m x s(-1), s = 0.4 vs. 4.2 m x s(-1), s = 0.4) while the EMG amplitude remained the same. Force decline rate was less (P < 0.05) during alkalosis-sustained maximal contraction and no differences were shown in central activation ratio. These data indicate that induced metabolic alkalosis can increase muscle fibre conduction velocity following prolonged submaximal cycling.
-
8.
A single protein meal increases recovery of muscle function following an acute eccentric exercise bout.
Etheridge, T, Philp, A, Watt, PW
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2008;(3):483-8
Abstract
The purpose of this study was to examine the effects of acute protein ingestion on the recovery of muscle function and markers of muscle damage in the 72 h post eccentric-exercise. Nine recreationally active males recorded quadriceps maximum isometric voluntary contraction (MVC), peak 5 s power output (PPO), and perceived muscle soreness. Plasma creatine kinase (CK) and protein carbonyl (PC) content were measured prior to exercise. Delayed-onset muscle soreness (DOMS) was induced by a 30 min downhill run (-10 degrees ) at a target intensity of 75% age-predicted heart rate maximum, immediately followed by ingestion of 100 g protein (containing 40 g essential amino acids; PRO) or placebo (CON) solution. The pre-exercise measures were re-taken in the subsequent 24, 48, and 72 h. CK, PC, and perceived muscle soreness increased significantly following exercise and with each supplement at 24 h. PC and muscle soreness remained elevated at 48 and 72 h (p < 0.05), whereas CK returned to baseline values. No difference between conditions was observed for these measures. Peak MVC significantly declined in CON to -7.9% at 24 h, reaching a nadir of -10% at 48 h (p < 0.05). In the PRO group, MVC remained within pre-exercise values at all time points. PPO followed a similar trend, reaching its nadir of -8.7% at 48 h in CON (p < 0.05), but had recovered in the PRO trial. Ingestion of a single post-exercise protein mixture increases the rate of force and power restoration at 48 h, suggesting potential for protein as an ergogenic aid during the DOMS period.
-
9.
Plasmatic markers of muscular stress in isokinetic exercise.
Speranza, L, Grilli, A, Patruno, A, Franceschelli, S, Felzani, G, Pesce, M, Vinciguerra, I, De Lutiis, MA, Felaco, M
Journal of biological regulators and homeostatic agents. 2007;(1-2):21-9
Abstract
In this paper we examined the variations of plasmatic concentrations of hypoxanthine and xanthine, and their relation with other important indicators of muscular stress creatine-kinase (CK), myoglobin, uric acid, leucocytes, in prolonged, isokynetic physical exercise, performed in a concentric mode at different joint excursion. Twenty healthy male subjects performed isokinetic exercises in concentric-concentric mode, with joint excursion of 30, 60, 90 deg/sec. Blood samples were drawn at rest, immediately after exercise and after 45 min of recovery. The plasmatic concentration of hypoxanthine increased at the end of physical exercise, compared to the rest value of about 1,5 micromol/L, up to a level of greater than 19 micromol/L; the values were higher after a period of recovery of 45 min and the increase varies considerably according to the type of exercise that was performed. Myoglobin has a slight but sensible increment too, with the same trend as hypoxanthine, while CK increase without correlation to the type of exercises. The relation with other indicators of muscular activity demonstrates that in none of the different isokinetic exercises, performed at concentric mode, was there ultrastructural damage, while it is possible to come across a considerable metabolic stress, which is dissimilar in the different kinds of exercises. The results suggest that hypoxanthine can be useful in monitoring the effectiveness of a work load and the metabolic stress consequences on the muscle tissue in training or rehabilitation programs. The results also suggest that even myoglobin, at small concentrations, can have the same function.
-
10.
Effects of beta-alanine supplementation on the onset of neuromuscular fatigue and ventilatory threshold in women.
Stout, JR, Cramer, JT, Zoeller, RF, Torok, D, Costa, P, Hoffman, JR, Harris, RC, O'Kroy, J
Amino acids. 2007;(3):381-6
Abstract
This study examined the effects of 28 days of beta-alanine supplementation on the physical working capacity at fatigue threshold (PWCFT), ventilatory threshold (VT), maximal oxygen consumption (VO2-MAX), and time-to-exhaustion (TTE) in women. Twenty-two women (age+/-SD 27.4+/-6.1 yrs) participated and were randomly assigned to either the beta-alanine (CarnoSyn) or Placebo (PL) group. Before (pre) and after (post) the supplementation period, participants performed a continuous, incremental cycle ergometry test to exhaustion to determine the PWCFT, VT, VO2-MAX, and TTE. There was a 13.9, 12.6 and 2.5% increase (p<0.05) in VT, PWCFT, and TTE, respectively, for the beta-alanine group, with no changes in the PL (p>0.05). There were no changes for VO2-MAX (p>0.05) in either group. Results of this study indicate that beta-alanine supplementation delays the onset of neuromuscular fatigue (PWCFT) and the ventilatory threshold (VT) at submaximal workloads, and increase in TTE during maximal cycle ergometry performance. However, beta-alanine supplementation did not affect maximal aerobic power (VO2-MAX). In conclusion, beta-alanine supplementation appears to improve submaximal cycle ergometry performance and TTE in young women, perhaps as a result of an increased buffering capacity due to elevated muscle carnosine concentrations.