scholarly journals Sex differences in muscle fatigue following isokinetic muscle contractions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miguel Gomes ◽  
Paulo Santos ◽  
Paulo Correia ◽  
Pedro Pezarat-Correia ◽  
Goncalo V. Mendonca
Keyword(s):  
Sex Differences ◽  
Muscle Fatigue ◽  
Human Performance ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Limiting Factor ◽  
Maximal Voluntary Isometric Contraction ◽  
Isokinetic Exercise ◽  
Isokinetic Contractions ◽  
The Impact

AbstractMuscle fatigue is a limiting factor of human performance. It is unclear whether sex-based differences in fatigability exist during dynamic exercise of varying velocities of contraction. We aimed at exploring sex differences in muscle fatigue elicited by maximal isokinetic muscle contractions performed at different angular velocities. Twenty-six healthy participants (13 men: 23.2 ± 1.5; 13 women: 21.9 ± 3.0 years) were tested for concentric knee-extension at slow, moderate and fast angular isokinetic velocity (60, 180 and 300º.s−1, respectively), on non-consecutive days. The impact of sex on fatigue resistance and consecutive recovery for each isokinetic condition was explored by calculating the percent change in maximal voluntary isometric contraction (MVIC) and in rate of torque development (RTD), from pre- to post-isokinetic exercise (30 repetitions). The isokinetic fatigue index was also determined. No sex differences were obtained in response to isokinetic contractions completed at 60º.s−1. After performing muscle contractions at 300º.s−1, women had a significantly greater loss in MVIC than men (− 18.4 ± 5.5 vs. − 12.9 ± 3.8%; p = 0.009) and larger decreases in work output during isokinetic exercise (− 34.2 ± 8.9 vs − 27.5 ± 10.6%; p = 0.017). Recovery of initial MVIC strength was greater for women post-exercise at 180º.s−1 (15.6 ± 4.1% vs. 6.7 ± 9.5; p = 0.003). No differences were found between sexes in any condition for RTD from pre- to post-fatigue. These results suggest the presence of a sexually dimorphic fatigability in response to dynamic (isokinetic) contractions favouring men at higher absolute velocities of contraction.

scholarly journals Sex Differences in Muscle Fatigue Following Isokinetic Muscle Contractions

2020 ◽  
Author(s):  
Miguel Gomes ◽  
Paulo Santos ◽  
Paulo Correia ◽  
Pedro Pezarat-Correia ◽  
Goncalo V. Mendonca
Keyword(s):  
Sex Differences ◽  
Muscle Fatigue ◽  
Human Performance ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Limiting Factor ◽  
Maximal Voluntary Isometric Contraction ◽  
Isokinetic Exercise ◽  
Isokinetic Contractions ◽  
The Impact

Abstract Muscle fatigue is a limiting factor of human performance. It is unclear whether sex-based differences in fatigability exist during dynamic exercise of varying velocities of contraction. We aimed at exploring sex differences in muscle fatigue elicited by maximal isokinetic muscle contractions performed at different angular velocities. Twenty-six healthy participants (13 men: 23.2 ± 1.5; 13 women: 21.9 ± 3.0 years) were tested for knee-extension at slow, moderate and fast angular velocity (60, 180 and 300º.s-1, respectively). The impact of sex on fatigue resistance and consecutive recovery for each isokinetic condition was explored by calculating the percent change in maximal voluntary isometric contraction (MVIC) and in rate of torque development (RTD), from pre- to post-isokinetic exercise. The isokinetic fatigue index was also determined. No sex differences were obtained in response to isokinetic contractions completed at 60º.s-1. After performing muscle contractions at 300º.s-1, women had a significantly greater loss in MVIC than men (-18.4 ± 5.5 vs. -12.9 ± 3.8%; p = 0.009) and larger decreases in work output during isokinetic exercise (-34.2 ± 8.9 vs -27.5 ± 10.6 %; p = 0.017). Recovery of initial MVIC strength was greater for women post-exercise at 180º.s-1 (6.7 ± 9.5 vs. 15.6 ± 4.1%; p = 0.003). No differences were found between sexes in any condition for RTD from pre- to post- fatigue. These results suggest the presence of a sexually dimorphic fatigability in response to dynamic (isokinetic) contractions favouring men at higher velocities of contraction.

Influences of repetitive muscle contractions with different modes on tendon elasticity in vivo

2001 ◽  
Vol 91 (1) ◽  
pp. 277-282 ◽  
Author(s):  
Keitaro Kubo ◽  
Hiroaki Kanehisa ◽  
Yasuo Kawakami ◽  
Tetsuo Fukunaga
Keyword(s):  
Vastus Lateralis ◽  
Force Production ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Vastus Lateralis Muscle ◽  
Maximal Voluntary Isometric Contraction ◽  
Duration Of Action ◽  
Before And After ◽  
Endurance Tests

The present study aimed to investigate the effects of repetitive muscle contractions on the elasticity of human tendon structures in vivo. Before and after each endurance test, the elongation of the tendon and aponeurosis of vastus lateralis muscle ( L) was directly measured by ultrasonography while the subjects performed ramp isometric knee extension up to maximal voluntary isometric contraction (MVC). Six male subjects performed muscle endurance tests that consisted of knee extension tasks with four different contraction modes: 1) 50 repetitions of maximal voluntary eccentric action for 3 s with 3 s of relaxation (ET1), 2) three sets of 50 repetitions of MVC for 1 s with 3 s of relaxation (ET2), 3) 50 repetitions of MVC for 3 s with 3 s of relaxation (ET3), and 4) 50 repetitions of 50% MVC for 6 s with 6 s of relaxation (ET4). In ET1 and ET2, there were no significant differences in L values at any force production levels between before and after endurance tests. In the cases of ET3 and ET4, however, the extent of elongation after the completion of the tests tended to be greater. The L values above 330 N in ET3 and 440 N in ET4, respectively, were significantly greater after endurance tests than before. These results suggested that the repeated longer duration contractions would make the tendon structures more compliant and that the changes in the elasticity might be not be affected by either muscle action mode or force production level but by the duration of action.

scholarly journals Activation of human quadriceps femoris muscle during dynamic contractions: effects of load on fatigue

2000 ◽  
Vol 89 (3) ◽  
pp. 926-936 ◽  
Author(s):  
Samuel C. K. Lee ◽  
Cara N. Becker ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Electrical Stimulation ◽  
Muscle Fatigue ◽  
Skeletal Muscles ◽  
Average Power ◽  
Knee Extension ◽  
Limiting Factor ◽  
Functional Activities ◽  
Dynamic Contractions ◽  
Shortening Contractions ◽  
Femoris Muscle

Muscle fatigue is both multifactorial and task dependent. Electrical stimulation may assist individuals with paralysis to perform functional activities [functional electrical stimulation (FES), e.g., standing or walking], but muscle fatigue is a limiting factor. One method of optimizing force is to use stimulation patterns that exploit the catchlike property of skeletal muscle [catchlike-inducing trains (CITs)]. Although nonisometric (dynamic) contractions are important parts of both normal physiological activation of skeletal muscles and FES, no previous studies have attempted to identify the effect that the load being lifted by a muscle has on the fatigue produced. This study examined the effects of load on fatigue during dynamic contractions and the augmentation produced by CITs as a function of load. Knee extension in healthy subjects was electrically elicited against three different loads. The highest load produced the least excursion, work, and average power, but it produced the greatest fatigue. CIT augmentation was greatest at the highest load and increased with fatigue. Because CITs were effective during shortening contractions for a variety of loads, they may be of benefit during FES applications.

Limits to human performance caused by muscle fatigue

2004 ◽  
pp. 7-10
Author(s):  
David Allen ◽  
Jan Lännergren ◽  
Håkan Westerblad
Keyword(s):  
Muscle Fatigue ◽  
Human Performance

Sex Differences in Anxiety Disorders

2019 ◽  
pp. 404-432
Author(s):  
Teresa A. Piggott ◽  
Alexandra N. Duran ◽  
Isha Jalnapurkar ◽  
Tyler Kimm ◽  
Stephanie Linscheid ◽  
...  
Keyword(s):  
Sex Differences ◽  
Anxiety Disorder ◽  
Anxiety Disorders ◽  
Stress Disorder ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Considerable Research ◽  
Psychosocial Influences ◽  
Psychiatric Conditions ◽  
The Impact

Women are more likely than men to meet lifetime criteria for an anxiety disorder. Moreover, anxiety is a risk factor for the development of other psychiatric conditions, including major depression. Numerous studies have identified evidence of sex differences in anxiety disorders, and there is considerable research concerning factors that may contribute to vulnerability for anxiety in females. In addition to psychosocial influences, biological components such as the female reproductive hormone cycle have also been implicated. Although psychotropic medication is more likely to be prescribed to women, there is little controlled data available concerning sex differences in the efficacy and/or tolerability of pharmacotherapy in anxiety disorders. This chapter provides an overview of the impact of gender in the epidemiology, phenomenology, course, and treatment response in generalized anxiety disorder (GAD), social anxiety disorder (SAD), posttraumatic stress disorder (PTSD), panic disorder (PD), and obsessive-compulsive disorder (OCD).

scholarly journals The Impact of Shape-Based Cue Discriminability on Attentional Performance

Vision ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 18
Author(s):  
Olga Lukashova-Sanz ◽  
Siegfried Wahl ◽  
Thomas S. A. Wallis ◽  
Katharina Rifai
Keyword(s):  
Temporal Processing ◽  
Visual Cues ◽  
Human Performance ◽  
Covert Attention ◽  
Orientation Discrimination ◽  
Know How ◽  
Processing Times ◽  
Attentional Performance ◽  
Cue Processing ◽  
The Impact

With rapidly developing technology, visual cues became a powerful tool for deliberate guiding of attention and affecting human performance. Using cues to manipulate attention introduces a trade-off between increased performance in cued, and decreased in not cued, locations. For higher efficacy of visual cues designed to purposely direct user’s attention, it is important to know how manipulation of cue properties affects attention. In this verification study, we addressed how varying cue complexity impacts the allocation of spatial endogenous covert attention in space and time. To gradually vary cue complexity, the discriminability of the cue was systematically modulated using a shape-based design. Performance was compared in attended and unattended locations in an orientation-discrimination task. We evaluated additional temporal costs due to processing of a more complex cue by comparing performance at two different inter-stimulus intervals. From preliminary data, attention scaled with cue discriminability, even for supra-threshold cue discriminability. Furthermore, individual cue processing times partly impacted performance for the most complex, but not simpler cues. We conclude that, first, cue complexity expressed by discriminability modulates endogenous covert attention at supra-threshold cue discriminability levels, with increasing benefits and decreasing costs; second, it is important to consider the temporal processing costs of complex visual cues.

scholarly journals Vulnerability factors for mephedrone-induced conditioned place preference in rats—the impact of sex differences, social-conditioning and stress

2021 ◽  
Author(s):  
Olga Wronikowska ◽  
Maria Zykubek ◽  
Łukasz Kurach ◽  
Agnieszka Michalak ◽  
Anna Boguszewska-Czubara ◽  
...  
Keyword(s):  
Sex Differences ◽  
Conditioned Place Preference ◽  
Low Dose ◽  
Social Factor ◽  
Place Preference ◽  
Female Rats ◽  
Male Rats ◽  
Social Conditioning ◽  
Male And Female Rats ◽  
The Impact

Abstract Rationale Mephedrone is a frequently overused drug of abuse that belongs to the group of novel psychoactive substances. Although its mechanism of action, as well as toxic and psychoactive effects, has been widely studied, the role of different factors that could contribute to the increased vulnerability to mephedrone abuse is still poorly understood. Objectives The aim of the presented study was to assess the impact of several factors (sex differences, social-conditioning, and chronic mild unpredictable stress — CMUS) on the liability to mephedrone-induced reward in Wistar rats. Methods The rewarding effects of mephedrone in male and female rats were assessed using the conditioned place preference (CPP) procedure. Furthermore, the impact of social factor and stress was evaluated in male rats using social-CPP and CMUS-dependent CPP, respectively. Results Mephedrone induced classic-CPP in female (10 mg/kg), as well as in male (10 and 20 mg/kg) rats. However, the impact of mephedrone treatment during social-CPP was highly dose-dependent as the rewarding effects of low dose of mephedrone (5 mg/kg; non-active in classic-CPP) were potentiated when administered during social-conditioning. Interestingly, social-conditioning with a higher dose of 20 mg/kg (that induced classic-CPP) was able to reverse these effects. Finally, CMUS potentiated rewarding effects of a low dose of mephedrone (5 mg/kg) and increased the level of corticosterone in rats’ prefrontal cortex and hippocampus. Conclusions Altogether, the presented results give new insight into possible factors underlying the vulnerability to mephedrone abuse and can serve as a basis for further studies assessing mechanisms underlying observed effects.

scholarly journals Sex differences in self-report anxiety and sleep quality during COVID-19 stay-at-home orders

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeremy A. Bigalke ◽  
Ian M. Greenlund ◽  
Jason R. Carter
Keyword(s):  
Sex Differences ◽  
Sleep Quality ◽  
State Anxiety ◽  
Severity Index ◽  
Self Report ◽  
Analysis Of Covariance ◽  
Chi Square ◽  
Perceived Impact ◽  
The Impact ◽  
At Home

Abstract Background COVID-19 and home isolation has impacted quality of life, but the perceived impact on anxiety and sleep remains equivocal. The purpose of this study was to assess the impact of COVID-19 and stay-at-home orders on self-report anxiety and sleep quality, with a focus on sex differences. We hypothesized that the COVID-19 pandemic would be associated with increased anxiety and decreased sleep quality, with stronger associations in women. Methods One hundred three participants (61 female, 38 ± 1 years) reported perceived changes in anxiety and sleep quality due to stay-at-home orders during the COVID-19 pandemic and were administered the Spielberger State-Trait Anxiety Inventory (STAI), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI). Chi-square and T test analyses were utilized to assess sex differences in reported anxiety and sleep. Analysis of covariance was used to compare the associations between reported impact of COVID-19 and anxiety/sleep parameters. Results Women (80.3%) reported higher prevalence of increased general anxiety due to COVID-19 when compared to men (50%; p = 0.001) and elevated STAI state anxiety compared to men (43 ± 1 vs. 38 ± 1 a.u., p = 0.007). Despite these differences in anxiety, the perceived impact of COVID-19 on PSQI was not different between sexes. However, when stratified by perceived changes in anxiety due to COVID-19, participants with higher anxiety responses to COVID-19 had higher ISI compared to those with no perceived changes in anxiety (9 ± 1 vs. 5 ± 1 a.u., p = 0.003). Additionally, participants who reported reduced sleep quality due to COVID-19 reported higher state anxiety (45 ± 1 a.u.) compared to those that perceived no change (36 ± 2 a.u., p = 0.002) or increased (36 ± 2 a.u., p < 0.001) sleep quality. Conclusion COVID-19 and state-ordered home isolation was associated with higher anxiety and reduced sleep quality, with a stronger association in women with respect to anxiety.

Discipline and Sex Differences in Angle-specific Isokinetic Analysis in Elite Skiers

2019 ◽  
Vol 40 (05) ◽  
pp. 317-330 ◽  
Author(s):  
Marine Alhammoud ◽  
Baptiste Morel ◽  
Clint Hansen ◽  
Mathew Wilson ◽  
Regis Mecca ◽  
...  
Keyword(s):  
Statistical Parametric Mapping ◽  
Knee Extension ◽  
Current Data ◽  
Screening Methods ◽  
Full Extension ◽  
Isokinetic Testing ◽  
Parametric Mapping ◽  
National Team ◽  
Alpine Skiers ◽  
The Impact

AbstractStandard outcomes of traditional isokinetic testing do not detect differences between various muscle mechanical properties. This study i) explored a novel analysis throughout the range of motion based on statistical parametric mapping and ii) examined the impact of sex and discipline on hamstrings/quadriceps torque in elite alpine skiers. Twenty-eight national team skiers (14 females, 14 males; 14 technical, 14 speed) undertook an isokinetic evaluation of the knee flexors/extensors (range 30–90°, 0° representing full extension). There was no effect of sex (p=0.864, d=0.03) and discipline (p=0.360, d=0.17) on maximal hamstrings-to-quadriceps ratio and no effect of discipline on maximal torque (p>0.156, d≤0.25). Hamstrings torque and hamstrings-to-quadriceps ratio were lower in females than males toward knee extension only (p<0.05). Quadriceps torque was greater after 72° of knee flexion in technicians than downhill skiers (p<0.05). The current data showed that statistical parametric mapping analysis identified angle-specific differences that could not be evidenced when analyzing only maximal torques and reconstructed ratios. This may enhance screening methods to identify pathologic knee function or monitor rehabilitation programs, and inform sex- and discipline-specific training in alpine skiing.

scholarly journals The Effects of Repetitive Drop Jumps on Impact Phase Joint Kinematics and Kinetics

2011 ◽  
Vol 27 (2) ◽  
pp. 108-115 ◽  
Author(s):  
Joshua T. Weinhandl ◽  
Jeremy D. Smith ◽  
Eric L. Dugan
Keyword(s):  
Energy Absorption ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Joint Kinematics ◽  
Knee Extensors ◽  
Initial Contact ◽  
Drop Jumps ◽  
Impact Phase ◽  
The Impact ◽  
Kinematics And Kinetics

The purpose of the study was to investigate the effects of fatigue on lower extremity joint kinematics, and kinetics during repetitive drop jumps. Twelve recreationally active males (n= 6) and females (n= 6) (nine used for analysis) performed repetitive drop jumps until they could no longer reach 80% of their initial drop jump height. Kinematic and kinetic variables were assessed during the impact phase (100 ms) of all jumps. Fatigued landings were performed with increased knee extension, and ankle plantar flexion at initial contact, as well as increased ankle range of motion during the impact phase. Fatigue also resulted in increased peak ankle power absorption and increased energy absorption at the ankle. This was accompanied by an approximately equal reduction in energy absorption at the knee. While the knee extensors were the muscle group primarily responsible for absorbing the impact, individuals compensated for increased knee extension when fatigued by an increased use of the ankle plantar flexors to help absorb the forces during impact. Thus, as fatigue set in and individuals landed with more extended lower extremities, they adopted a landing strategy that shifted a greater burden to the ankle for absorbing the kinetic energy of the impact.

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