scholarly journals Sex Influence on the Functional Recovery Pattern After a Graded Running Race: Original Analysis to Identify the Recovery Profiles

2021 ◽  
Vol 12 ◽  
Author(s):  
Robin Macchi ◽  
Fabrice Vercruyssen ◽  
Arnaud Hays ◽  
Gaetan Aubert ◽  
Gaetan Exubis ◽  
...  
Keyword(s):  
Functional Recovery ◽  
Triceps Surae ◽  
Knee Extensors ◽  
Major Influence ◽  
Sex Influence ◽  
Recovery Pattern ◽  
Time Interaction ◽  
Key Variables ◽  
Muscle Groups ◽  
Voluntary Contractions

This study investigated the sex influence on the acute and delayed fatigue effects of a 20 km graded running race. Eighteen recreational runners, 10 women and 8 men, completed the race. The testing protocol included five sessions: a week before the race (PRE), 35 ± 15 min after (POST), 2 h, 2 and 4 days (2D and 4D) later. Each session included uni- and bilateral maximal isometric voluntary contractions of the knee extensors (MVC), a squat jump (SJ), and a drop jump (DJ). Acute and delayed muscle soreness (DOMS) were evaluated for the quadriceps, hamstring and triceps surae muscle groups. The 2D and 4D sessions included also a horizontal force-velocity test (HF-V) performed under five resistive conditions. For each test, a set of key variables was computed to characterize the lower limb functional recovery. Mixed ANOVA analyses revealed significant (sex × time) interactions, with larger acute drops for men in MVCs and earlier recovery for women in the bilateral MVC (p < 0.001) and DJ (p < 0.05) tests. Only women reported DOMS for the hamstrings at 2D (p < 0.001) and showed small improvements in pure concentric SJ (p < 0.05) and HF-V (p < 0.01) tests at 4D. As expected, DOMS disappeared prior to the complete functional recovery. These results confirmed the combined influence of testing task and sex on the functional recovery pattern while supporting a lesser and faster recovery in women. The originality of this study lies in the complexity and sex-dependence of the functional recovery pattern revealed by a multiple factorial analysis which was used to identify the most discriminating tests and variables in the recovery pattern. The obtained clusters highlighted some recovery profiles associated with greater risks of injury when starting to run again. However, the lack of sex × time interaction for normalized values emphasizes the major influence of men’s initially higher functional values compared to women.

Muscle architecture and force-velocity relationships in humans

1984 ◽  
Vol 57 (2) ◽  
pp. 435-443 ◽  
Author(s):  
T. L. Wickiewicz ◽  
R. R. Roy ◽  
P. L. Powell ◽  
J. J. Perrine ◽  
V. R. Edgerton
Keyword(s):  
Peak Torque ◽  
Knee Extensors ◽  
Major Influence ◽  
Inhibitory Mechanism ◽  
Cross Sectional ◽  
Isokinetic Testing ◽  
Force Velocity ◽  
Muscle Groups ◽  
Knee Flexors

The in vivo torque-velocity relationships of the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF), and ankle dorsiflexors (DF) were determined in 12 untrained subjects using an isokinetic testing device (Cybex II). These data were then matched to the predicted maximum forces and shortening velocities derived from muscle architectural determinations made on three hemipelvectomies (36). The torque-velocity curves of all muscle groups resembled that predicted by Hill's (19, 20) equation except at the higher forces and lower velocities. The peak torques occurred at mean velocities ranging from 41–62 rad X s-1 for the KE, KF, and PF. Although the peak torque of the DF occurred at the isometric loading condition, it was also lower than that predicted by Hill's equation. The muscle fiber length and physiological cross-sectional area measurements indicate that the architecture of the human leg musculature has a major influence on the torque-velocity characteristics. These data corroborate previous findings (24) that some neural inhibitory mechanism exists in the control of the leg musculature, which limits the maximum forces that could be produced under optimal stimulating conditions.

scholarly journals Spinal contribution to neuromuscular recovery differs between elbow-flexor and knee-extensor muscles after a maximal sustained fatiguing task

2020 ◽  
Vol 124 (3) ◽  
pp. 763-773 ◽  
Author(s):  
Gianluca Vernillo ◽  
John Temesi ◽  
Matthieu Martin ◽  
Renata L. Krüger ◽  
Guillaume Y. Millet
Keyword(s):  
Knee Extensor ◽  
Elbow Flexor ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Recovery Pattern ◽  
Motoneuron Excitability ◽  
Neural Processes ◽  
Extensor Muscles ◽  
Voluntary Contractions ◽  
Knee Extensor Muscles

By comparing the changes in motoneuron excitability in elbow-flexor and knee-extensor muscles after sustained fatiguing maximal voluntary contractions, this study shows that motoneuron recovery behavior depends on the muscle performing the exercise. A different recovery pattern in motoneuron excitability occurs in elbow flexors as it recovered by 60 s whereas knee extensors were unaffected by fatigue. This finding can help to increase understanding of the effect of a fatigue and subsequent recovery on neural processes.

Effects of the use neuromuscular electrical stimulation of the lower extremities in the prehabilitation of patients in a before cardiac surgery

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
P Oleinik ◽  
AN Sumin ◽  
AV Bezdenezhnykh
Keyword(s):  
Cardiac Surgery ◽  
Handgrip Strength ◽  
Lower Extremities ◽  
Left Knee ◽  
Knee Extensors ◽  
Control Group ◽  
Elective Cardiac Surgery ◽  
Antagonist Muscles ◽  
Muscle Groups ◽  
Knee Flexors

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Research Institute for Complex Issues of Cardiovascular Diseases Aim To evaluate the effects of neuromuscular electrostimulation in the prehabilitation and prevention of muscle weakness in patients awaiting cardiac surgery. Materials and methods 122 patients waiting for elective cardiac surgery were included. Exclusion criteria: age less than 25 and more than 80 years; emergency and urgent surgical interventions; arthropathies; low pain threshold; rhabdomyolysis and other myopathies; cognitive dysfunction. Routine laboratory and instrumental examinations were performed in all patients upon admission to the hospital, as part of a standard examination. 62 patients were randomly selected for the preoperative NMES group, in addition to the standard preoperative preparation and treatment program. The standard program included 60 control patients. Patients of the NMES group underwent quadriceps stimulation for at least 5 sessions, lasting 90 minutes, daily before surgery. Results. The groups were comparable and did not have significant differences in gender and age characteristics, according to the main clinical and anamnestic data and types of operations. Initially, there were no differences in the state of the muscles of the lower extremities, the distance of the six-minute walking test (6MWT), and the strength of the hand grip. After NMES, there was an increase in muscle strength relative to the control group, both stimulated muscle groups and unstimulated antagonist muscles, as well as a greater 6MWT distance and hand compression force. All the differences were significant. Conclusions The course of pre-rehabilitation of NMES before surgery, allowed to maintain, and in some cases improve the condition of the muscle frame of the lower extremities. A positive effect was observed not only in stimulated muscle groups, but also in antagonist muscles Indicators of muscle status NMES (n = 62) Control group (n = 60) Baseline Discharge Baseline Discharge P-level Right knee extensors strength (kg) 24,4 [18,3; 31,4] 30,4 [23,8; 36,2]* 24,7 [20,1; 33,2] 22,25 [18,9; 30,4] <0,001 Left knee extensors strength (kg) 23,8 [19,3; 31,3] 29,2 [23,6; 35,4]* 25,75 [19,2; 31,3] 22,9 [18,9; 27,8] <0,001 Right knee flexors strength (kg) 18,9 [13,3; 24,0] 21,7 [16,6; 25,1] 19,55 [13,1; 26,0] 16,7 [12,1; 23,3] 0,006 Left knee flexors strength (kg) 19,3 [14,3; 24,5] 21,9 [17,3; 26,7] 19,5 [13,0; 24,3] 18,2 [13,4; 22,2] 0,005 6-MWT (m) 300,0 [261,0; 371,0] 331,0 [280,0; 375,0] 304,5 [253,0; 380,0] 285,5 [246,0; 342,0] 0,006 Right handgrip strength (kg) 28,5 [20,5; 34,0] 31,5 [22,0; 34,0] 29,0 [19,0; 34,0] 27,0 [19,0; 33,0] 0,054 Left handgrip strength (kg) 25,0 [18,0; 31,0] 25,0 [18,0; 32,0] 24,0 [15,0; 31,0] 22,0 [14,0; 28,0] 0,062 * - p-level from baseline data < 0,05 Abstract Figure. dynamics of stimulated muscles

scholarly journals Isokinetic Profile of Elite Serbian Female Judoists

2021 ◽  
Vol 18 (13) ◽  
pp. 6988
Author(s):  
Wieslaw Blach ◽  
Miodrag Drapsin ◽  
Nemanja Lakicevic ◽  
Antonino Bianco ◽  
Tamara Gavrilovic ◽  
...  
Keyword(s):  
Knee Extensors ◽  
Training Experience ◽  
Lateral Asymmetry ◽  
National Team ◽  
Significant Difference ◽  
Judo Athletes ◽  
Muscle Groups ◽  
Torque Values ◽  
Training Modalities ◽  
Knee Flexors

Elite judo athletes undergo vigorous training to achieve outstanding results. In pursuit of achieving competitive success, the occurrence of injuries amongst judo athletes is not rare. The study aimed to perform a knee flexors and extensors isokinetic torque analysis in elite female judo athletes. Fifty-eight elite female judo athletes of the Serbian national team (21.02 ± 3.11 years; 62.36 ± 11.91 kg, 165.04 ± 10.24 cm, training experience 12.72 ± 2.98 years) volunteered to participate in this study. The range of motion (ROM) was set at 90⁰. Testing was performed in a concentric–concentric mode for the testing speed of 60 ⁰/s. Five maximal voluntary contractions of knee extensors and knee flexors muscle groups were measured for both legs. The obtained data showed a statistically significant difference in absolute torque values among different categories as heavier athletes demonstrated higher values. Post hoc analysis showed a significant difference between weight categories, as heavier athletes demonstrated higher values, while no significant differences in normalized torque values for different weight categories were observed. The implementation of new elements and training modalities may improve performance and prevent lateral asymmetry, thus reducing the risk of injury.

Unilateral isometric muscle fatigue decreases force production and activation of contralateral knee extensors but not elbow flexors

2014 ◽  
Vol 39 (12) ◽  
pp. 1338-1344 ◽  
Author(s):  
Israel Halperin ◽  
David Copithorne ◽  
David G. Behm
Keyword(s):  
Muscle Fatigue ◽  
Force Production ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Post Intervention ◽  
Nonlocal Effects ◽  
And Performance ◽  
Voluntary Contractions ◽  
Isometric Muscle

Nonlocal muscle fatigue occurs when fatiguing 1 muscle alters performance of another rested muscle. The purpose of the study was to investigate if fatiguing 2 separate muscles would affect the same rested muscle, and if fatiguing the same muscle would affect 2 separate muscles. Twenty-one trained males participated in 2 studies (n = 11; n = 10). Subjects performed 2 pre-test maximum voluntary contractions (MVCs) with the nondominant knee extensors. Thereafter they performed two 100-s MVCs with their dominant knee extensors, elbow flexors, or rested. Between and after the sets, a single MVC with the nondominant rested knee extensors was performed. Subsequently, 12 nondominant knee extensors repeated MVCs were completed. Force, quadriceps voluntary activation (VA), and electromyography (EMG) were measured. The same protocol was employed in study 2 except the nondominant elbow-flexors were tested. Study 1: Compared with control conditions, a significant decrease in nondominant knee extensors force, EMG, and VA was found under both fatiguing conditions (P ≤ 0.05; effect size (ES) = 0.91–1.15; 2%–8%). Additionally, decrements in all variables were found from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.82–2.40; 9%–20%). Study 2: No differences were found between conditions for all variables (P ≥ 0.33; ES ≤ 0.2; ≤3.0%). However, all variables decreased from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.4–3.0; 7.2%–19.7%). Whereas the rested knee extensors demonstrated nonlocal effects regardless of the muscle being fatigued, the elbow-flexors remained unaffected. This suggests that nonlocal effects are muscle specific, which may hold functional implications for training and performance.

scholarly journals Exercise tolerance during muscle contractions below and above the critical torque in different muscle groups

2018 ◽  
Vol 43 (2) ◽  
pp. 174-179 ◽  
Author(s):  
Leonardo Henrique Perinotto Abdalla ◽  
Benedito Sérgio Denadai ◽  
Natália Menezes Bassan ◽  
Camila Coelho Greco
Keyword(s):  
Exercise Intensity ◽  
Maximal Voluntary Contraction ◽  
Exercise Tolerance ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Isometric Contractions ◽  
Plantar Flexors ◽  
Significant Difference ◽  
Muscle Groups

The objective of this study was to test the hypotheses that end-test torque (ET) (expressed as % maximal voluntary contraction; MVC) is higher for plantar flexors (PF) than knee extensors (KE) muscles, whereas impulse above ET (IET) is higher for KE than PF. Thus, we expected that exercise tolerance would be longer for KE than PF only during the exercise performed above ET. After the determination of MVC, 40 men performed two 5-min all-out tests to determine ET and IET. Eleven participants performed a further 4 intermittent isometric tests, to exhaustion, at ET + 5% and ET – 5%, and 1 test for KE at the exercise intensity (%MVC) corresponding to ET + 5% of PF. The IET (7243.2 ± 1942.9 vs. 3357.4 ± 1132.3 N·m·s) and ET (84.4 ± 24.8 vs. 73.9 ± 19.5 N·m) were significantly lower in PF compared with KE. The exercise tolerance was significantly longer for PF (300.7 ± 156.7 s) than KE (156.7 ± 104.3 s) at similar %MVC (∼60%), and significantly shorter for PF (300.7 ± 156.7 s) than KE (697.0 ± 243.7 s) at ET + 5% condition. However, no significant difference was observed for ET – 5% condition (KE = 1030.2 ± 495.4 s vs. PF = 1028.3 ± 514.4 s). Thus, the limit of tolerance during submaximal isometric contractions is influenced by absolute MVC only during exercise performed above ET, which seems to be explained by differences on both ET (expressed as %MVC) and IET values.

Caffeine counteracts the ergogenic action of muscle creatine loading

1996 ◽  
Vol 80 (2) ◽  
pp. 452-457 ◽  
Author(s):  
K. Vandenberghe ◽  
N. Gillis ◽  
M. Van Leemputte ◽  
P. Van Hecke ◽  
F. Vanstapel ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Knee Extensors ◽  
Caffeine Intake ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Before And After ◽  
And Performance ◽  
Exercise Fatigue ◽  
Voluntary Contractions

This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.

scholarly journals Development of Lower Extremity Strength in Ambulatory Children With Bilateral Spastic Cerebral Palsy in Comparison With Typically Developing Controls Using Absolute and Normalized to Body Weight Force Values

2021 ◽  
Vol 12 ◽  
Author(s):  
Nicolaos Darras ◽  
Eirini Nikaina ◽  
Magda Tziomaki ◽  
Georgios Gkrimas ◽  
Antigone Papavasiliou ◽  
...  
Keyword(s):  
Body Weight ◽  
Cerebral Palsy ◽  
Muscle Strength ◽  
Lower Limb ◽  
Age Groups ◽  
Knee Extensors ◽  
Spastic Cerebral Palsy ◽  
Typically Developing ◽  
Antagonist Muscles ◽  
Muscle Groups

This cross-sectional study aimed to examine the development of lower limb voluntary strength in 160 ambulatory patients with bilateral spastic cerebral palsy (CP) (106 diplegics/54 quadriplegics) and 86 typically developing (TD) controls, aged 7–16 years. Handheld dynamometry was used to measure isometric strength of seven muscle groups (hip adductors and abductors, hip extensors and flexors, knee extensors and flexors, and ankle dorsiflexors); absolute force (AF) values in pounds were collected, which were then normalized to body weight (NF). AF values increased with increasing age (p &lt; 0.001 for all muscle groups), whereas NF values decreased through adolescence (p &lt; 0.001 for all muscle groups except for hip abduction where p = 0.022), indicating that increases in weight through adolescence led to decreases in relative force. Both AF and NF values were significantly greater in TD subjects when compared with children with CP in all muscle and all age groups (p &lt; 0.001). Diplegics and quadriplegics demonstrated consistently lower force values than TD subjects for all muscle groups, except for the hip extensors where TD children had similar values with diplegics (p = 0.726) but higher than quadriplegics (p = 0.001). Diplegic patients also exhibited higher values than quadriplegics in all muscles, except for the knee extensors where their difference was only indicative (p = 0.056). The conversion of CP subjects' force values as a percentage of the TD subjects' mean value revealed a pattern of significant muscle strength imbalance between the CP antagonist muscles, documented from the following deficit differences for the CP muscle couples: (hip extensors 13%) / (hip flexors 32%), (adductors 27%) / (abductors 52%), and (knee extensors 37%) / (knee flexors 53%). This pattern was evident in all age groups. Similarly, significant force deficiencies were identified in GMFCS III/IV patients when compared with TD children and GMFCS I/II patients. In this study, we demonstrated that children and adolescents with bilateral CP exhibited lower strength values in lower limb muscles when compared with their TD counterparts. This difference was more prevalent in quadriplegic patients and those with a more severe impairment. An important pattern of muscle strength imbalance between the antagonist muscles of the CP subjects was revealed.

Developmental Changes in Isometric Strength: Longitudinal Study in Adolescent Soccer Players

2018 ◽  
Vol 39 (09) ◽  
pp. 688-695 ◽  
Author(s):  
Joao Duarte ◽  
João Valente-dos-Santos ◽  
Manuel Coelho-e-Silva ◽  
R. Malina ◽  
Dieter Deprez ◽  
...  
Keyword(s):  
Skeletal Maturity ◽  
Isometric Strength ◽  
Fat Free Mass ◽  
Knee Extensors ◽  
Annual Increment ◽  
Systematic Assessment ◽  
Dependent Variables ◽  
Muscle Groups ◽  
Knee Muscle ◽  
Knee Flexors

AbstractThis study aimed to examine longitudinal changes in isometric strength of the knee extensors (ImKE) and knee flexors (ImKF) at 30° and 60°. The sample was composed of 67 players aged 11.0–13.9 years at baseline over five years. Stature, body mass, skinfolds, and isometric strength (ImKE30°, ImKF30°, ImKE60° and ImKF60°) were measured. Fat mass and fat-free mass (FFM) were derived from skinfolds. Skeletal age was obtained using TW2 RUS. Multilevel random effects regression analyses extracted developmental polynomial models. An annual increment on chronological age (CA) corresponded to 5.6 N (ImKE30°), 2.7 N (ImKF30°), 4.6 N (ImKE60°) and 1.5 N (ImKF60°). An increment of 1 kg in FFM predicted isometric strength as follows: 1.2 N (ImKE30°), 2.1 N (ImKF30°), 3.1 N (ImKE60°) and 2.0 N (ImKF60°). The following equations were obtained: ImKE30°=5.759×CA+1.163×FFM; ImKF30°=−19.369+2.691×CA+0.693×CA2+2.108×FFM; ImKE60°=4.553×CA+3.134×FFM; and, ImKF60°=-19.669+1.544×CA+2.033×FFM. Although skeletal maturity had a negligible effect on dependent variables, age and body size, based on FFM, were relevant longitudinal predictors. During adolescence, systematic assessment of knee extensors and knee flexors are strongly recommended to prevent impairment of knee muscle groups.

The Effect of Heating and Cooling on Time Course of Voluntary and Electrically Induced Muscle Force Variation

Medicina ◽  
2011 ◽  
Vol 47 (1) ◽  
pp. 6 ◽  
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Muscle Fatigue ◽  
Time Course ◽  
Muscle Force ◽  
Peak Torque ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Lower Body ◽  
Heating And Cooling ◽  
Force Variation ◽  
Voluntary Contractions

The aim of this study was to investigate the effect of heating and cooling on time course of voluntary and electrically induced muscle force variation. Material and Methods. Ten volunteers performed 50 maximal voluntary and electrically induced contractions of the knee extensors at an angle of 120 degrees under the control conditions and after passive lower body heating and cooling in the control, heating, and cooling experiments. Peak torque, torque variation, and half-relaxation time were assessed during the exercise. Results. Passive lower body heating increased muscle and core temperatures, while cooling lowered muscle temperature, but did not affect core temperature. We observed significantly lower muscle fatigue during voluntary contraction compared with electrically induced contractions. Body heating (opposite to cooling) increased involuntarily induced muscle force, but caused greater electrically induced muscle fatigue. In the middle of the exercise, the coefficient of correlation for electrically induced muscle torque decreased significantly as compared with the beginning of the exercise, while during maximal voluntary contractions, this relation for torque remained significant until the end of the exercise. Conclusion. It was shown that time course of voluntary contraction was more stable than in electrically induced contractions.

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