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Background: Rating of perceived exertion (RPE) is considered a valid method for prescribing prolonged aerobic steady-state exercise (SSE) intensity due to its association with physiological indicators of exercise intensity, such as oxygen uptake (V̇O2) or heart rate (HR). However, these associations between psychological and physiological indicators of exercise intensity were found during graded exercise tests (GXT) but are currently used to prescribe SSE intensity even though the transferability and validity of the relationships found during GXT to SSE were not investigated. The present study aims to verify whether (a) RPE-HR or RPE-V̇O2 relations found during GXTs are valid during SSEs, and (b) the duration and intensity of SSE affect these relations. Methods: Eight healthy and physically active males (age 22.6 ± 1.2 years) were enrolled. On the first visit, pre-exercise (during 20 min standing) and maximal (during a GXT) HR and V̇O2 values were measured. Then, on separate days, participants performed 4 SSEs on the treadmill by running at 60% and 80% of the HR reserve (HRR) for 15 and 45 min (random order). Individual linear regressions between GXTs' RPE (dependent variable) and HRR and V̇O2 reserve (V̇O2R) values (computed as the difference between maximal and pre-exercise values) were used to predict the RPE associated with %HRR (RPEHRR) and %V̇O2R (RPEV̇O2R) during the SSEs. For each relation (RPE-%HRR and RPE-%V̇O2R), a three-way factorial repeated measures ANOVA (α = 0.05) was used to assess if RPE (dependent variable) was affected by exercise modality (i.e., RPE recorded during SSE [RPESSE] or GXT-predicted), duration (i.e., 15 or 45 min), and intensity (i.e., 60% or 80% of HRR). Results: The differences between RPESSE and GXT-predicted RPE, which were assessed by evaluating the effect of modality and its interactions with SSE intensity and duration, showed no significant differences between RPESSE and RPEHRR. However, when RPESSE was compared with RPEV̇O2R, although modality or its interactions with intensity were not significant, there was a significant (p = 0.020) interaction effect of modality and duration yielding a dissociation between changes of RPESSE and RPEV̇O2R over time. Indeed, RPESSE did not change significantly (p = 0.054) from SSE of 15 min (12.1 ± 2.0) to SSE of 45 min (13.5 ± 2.1), with a mean change of 1.4 ± 1.8, whereas RPEV̇O2R decreased significantly (p = 0.022) from SSE of 15 min (13.7 ± 3.2) to SSE of 45 min (12.4 ± 2.8), with a mean change of −1.3 ± 1.5. Conclusion: The transferability of the individual relationships between RPE and physiological parameters found during GXT to SSE should not be assumed as shown by the results of this study. Therefore, future studies modelling how the exercise prescription method used (e.g., RPE, HR, or V̇O2) and SSE characteristics (e.g., exercise intensity, duration, or modality) affect the relationships between RPE and physiological parameters are warranted. [ABSTRACT FROM AUTHOR]

Introduction: The COVID-19 pandemic induced an extraordinary impact on public mental health to a degree not completely understood, especially in vulnerable populations such as breast cancer (BC) survivors. In this study, we described the short- (after 3-month) and long- (after 12-month) term effects of a multidisciplinary home-based lifestyle intervention in Italian women BC survivors during the first year of COVID-19 pandemic. Materials and methods: In total, 30 Italian BC survivors with risk factors for recurrence took part in the ongoing MoviS trial (protocol: NCT 04818359). Between January 2020 and January 2021, a 3-month lifestyle intervention based on psychological counseling, nutrition, and exercise was carried out. Participants were asked to fill out psychological questionnaires for the assessment of quality of life (QoL) indicators (European Organization for Research and Treatment of Cancer QoL, EORTC-QLQ-C30) and psychological health measures such as fatigue (Brief Fatigue Inventory, BFI), distress (Distress Thermometer, DT and Psychological Distress Inventory, PDI), cancer-related fatigue (Verbal Rating Scale, VRS), and mood states (Profile of Mood States Questionnaire, POMS). IBM SPSS Statistical Software version 27.0 and R Project for Statistical Computing version 4.2.1 were used to process data. All participants were assessed at four time points: T0 (baseline), T1 (3-month), and follow-up at T2 and T3 (6- and 12-month, respectively) to measure primary (quality of life indicators) and secondary (psychological health) outcomes. Friedman non parametric test and Wilcoxon signed rank test (with Bonferroni correction) were conducted to investigate the statistically significant differences in psychometric scores and between assessment times. Results: Compared to baseline (T0), at T1 most of the QoL indicators (i.e., symptoms of fatigue and general health) were improved (p < 0.017) with the exception of a worsening in participants' social functioning ability. Also, perception of severity of fatigue, distress, cancer-related fatigue, depression, and anger enhanced. Compared to baseline (T0), at T3 we mainly observed a stable condition with T0-T1 pairwise comparison, however other secondary outcomes (i.e., fatigue mood state, confusion, and anxiety) significantly improved. Discussion: Our preliminary findings support the proposal of this lifestyle intervention for BC survivors. Despite the home-confinement due to the COVID-19 pandemic, the intervention surprisingly improved QoL indicators and psychological health of the participants. [ABSTRACT FROM AUTHOR]

This study aimed to assess if, during incremental exercise, considering individual characteristics can make the relationship between the percentages of heart rate (HRR) and oxygen uptake (V̇O2R) reserve either 1:1 or more accurate. Cycle ergometer data of the maximal incremental exercise tests performed by 450 healthy and sedentary participants (17-66 years) of the HERITAGE Family Study, grouped for sex, ethnicity, age, body fat, resting HR, and V̇O2max, were used to calculate the individual linear regressions between %HRR and %V̇O2R. The mean slope and intercept of the individual linear regressions of each subgroup were compared with 1 and 0 (identity line), respectively, using Hotelling tests followed by post-hoc one-sample t-tests. Two multiple linear regressions were also performed, using either the slopes or intercepts of the individual linear regressions as dependent variables and sex, age, resting HR, and V̇O2max as independent variables. The mean %HRR-%V̇O2R relationships of all subgroups differed from the identity line. Moreover, individual linear regression intercepts (8.9 ± 16.0) and slopes (0.971 ± 0.190) changed (p < 0.001) after 20 weeks of aerobic training (13.1 ± 11.1 and 0.891 ± 0.122). The multiple linear regressions could explain only 3.8% and 1.3% of the variance in the intercepts and slopes, whose variability remained high (standard error of estimate of 15.8 and 0.189). In conclusion, the %HRR-%V̇O2R relationship differs from the identity line regardless of individual characteristics and their difference increased after aerobic training. Moreover, due to the high interindividual variability, using a single equation for the whole population seems not suitable for representing the %HRR-%V̇O2R relationship of a given subject, even when several individual characteristics are considered. Highlights The association between %HRR and %V̇O2R is not 1:1 even when individuals are grouped by age, sex, ethnicity, body composition, HRrest, and V̇O2max. Using several subject characteristics to identify the individual's %HRR-%V̇O2R relationship does not meaningfully increase its prediction accuracy or reduce the interindividual variability of %HRR-%V̇O2R relationships Using a single equation for the whole population is not suitable for representing the relationship of a given subject; hence, individual relationships should be preferred when prescribing the intensity of aerobic exercise. The individual %HRR-%V̇O2R relationship should be periodically assessed due to the potential training induced changes in the relationship. [ABSTRACT FROM AUTHOR]

Background: Workplace exercise interventions showed good results, but lack of time was often reported as a barrier to participation. To overcome this problem, several studies attempted to implement short high-intensity interval training (HIT) within the workplace. Objectives: The aim of this systematic review is to explore the feasibility and effectiveness of HIT interventions within the workplace setting. Data sources: A systematic literature search was conducted in PubMed and SPORTDiscus to identify articles related to HIT within the workplace. Study eligibility criteria: Only interventions that consisted of HIT programmes within the workplace and tested at least one physiological, psychological, or work-related outcome were included. Results: Seven studies (317 participants) met the inclusion criteria. HIT interventions lasted 6–12 weeks, with a frequency of 2–4 sessions/week and a duration of 8–30 min per session. Feasibility was qualitatively investigated in four studies, with key positive aspects reported for HIT time-appeal, the sense of competence driven by individual intensity, and improved intention to exercise; five studies reported adherence rates > 80%. Small-to-large effect sizes were reported for improvements in cardiorespiratory and muscular fitness. Small-to-medium effect sizes were reported for blood parameters and health-related quality of life. Conclusions: HIT interventions in the workplace showed limited effectiveness in improving health-related outcomes, while promising results regarding feasibility were reported, mainly due to the time-efficiency and the positive post-exercise psychosocial responses. However, further high-quality studies involving more participants are still needed to make firm conclusions on HIT effectiveness and feasibility compared to other types of exercise in this context. [ABSTRACT FROM AUTHOR]

Exercise-released extracellular vesicles (EVs) are emerging as a novel class of exerkines that promotes systemic beneficial effects. However, slight differences in the applied exercise protocols in terms of mode, intensity and duration, as well as the need for standardized protocols for EV isolation, make the comparison of the studies in the literature extremely difficult. This work aims to investigate the EV amount and EV-associated miRNAs released in circulation in response to different physical exercise regimens. Healthy individuals were subjected to different exercise protocols: acute aerobic exercise (AAE) and training (AT), acute maximal aerobic exercise (AMAE) and altitude aerobic training (AAT). We found a tendency for total EVs to increase in the sedentary condition compared to trained participants following AAE. Moreover, the cytofluorimetric analysis showed an increase in CD81+/SGCA+/CD45− EVs in response to AAE. Although a single bout of moderate/maximal exercise did not impact the total EV number, EV-miRNA levels were affected as a result. In detail, EV-associated miR-206, miR-133b and miR-146a were upregulated following AAE, and this trend appeared intensity-dependent. Finally, THP-1 macrophage treatment with exercise-derived EVs induced an increase of the mRNAs encoding for IL-1β, IL-6 and CD163 using baseline and immediately post-exercise EVs. Still, 1 h post-exercise EVs failed to stimulate a pro-inflammatory program. In conclusion, the reported data provide a better understanding of the release of circulating EVs and their role as mediators of the inflammatory processes associated with exercise. [ABSTRACT FROM AUTHOR]

Soccer (football) practice can induce a limitation of ankle range of motion (ROM) that is a possible risk factor for injury and other negative consequences over time. The main objective of this research was to investigate the effects of soccer practice on ankle ROM throughout the entire period of a sports career of soccer players (SP). Furthermore, the relationship between ankle ROM and muscle strength in SP of different ages was studied. A total of 204 SP (range 6.7–45.1 years) and 87 controls (range: 7.5–45.2 years) matched for age, body mass index (BMI), and gender, were assessed. Ankle ROM in both plantar flexion (APF) and dorsiflexion (ADF) in addition to handgrip strength (HGS) were evaluated using an inclinometer and the Jamar hydraulic hand dynamometer, respectively. The comparison between SP and control groups showed a significant reduction in ankle ROM of both APF (26.3 ± 7.2° vs. 32.6 ± 7.4°; d = −0.90; p < 0.001) and ADF (95.5 ± 15.6° vs. 105.5 ± 15.8°; d = −0.66; p < 0.001). In SP, the results of the ANOVAs test indicate that age had a significant effect on ADF (F = 4.352, p = 0.038, partial eta-squared (ηp2) = 0.015) but not on APF (F = 0.430, p = 0.746, ηp2 = 0.001). Moreover, considering only the SP, a weak inverse correlation between ADF and HGS group ADF was found (rs = −0.27; p < 0.001). Factors such as the non-linear trend of growth in young SP could hinder the definition of the relationship between ankle ROM, age, and muscle strength. However, the appropriate consideration of age and muscle strength could facilitate the management of ankle ROM in PF of different ages. [ABSTRACT FROM AUTHOR]

Objective: The intensity of barbell bench press exercise is generally prescribed as the load to be lifted for a specific number of repetitions; however, other factors (e.g., execution velocity) can affect bench press exercise intensity. Moreover, no study assessed whether load distribution (i.e., the distance between the disc stacks on the two sides of the barbell) affects exercise intensity. The present study aims to assess how different combinations of load, velocity, and barbell load distribution affect the number of repetitions to failure (REPfailure), and rating of perceived exertion (RPEfatigue) and number of repetitions (REPfatigue) at fatigue onset. Methods: Ten males (age 23.3±1.8 years) performed bench press exercises to exhaustion using random combinations of three loads (50%, 65%, and 80% of 1 repetition maximum), three execution velocities (50%, 70%, and 90% of maximal concentric velocity), and two load distributions (narrow and wide). Three separate three-way repeated-measures ANOVAs were performed to assess the effect of load, velocity, and load distribution on REPfailure, RPEfatigue, and REPfatigue expressed as a percentage of REPfailure. Results: REPfailure was affected by load (p<0.001), velocity (p<0.001), and distribution (p = 0.005). The interactions between load and velocity (p<0.001) and load and distribution (p = 0.004) showed a significant effect on REPfailure, whereas the interaction between velocity and distribution was not significant (p = 0.360). Overall, more REPfailure were performed using lower loads, higher velocities, and a wider distribution. RPEfatigue and REPfatigue were affected by load (p<0.001 and p = 0.007, respectively) and velocity (p<0.001 and p<0.001, respectively), and not by distribution (p = 0.510 and p = 0.571, respectively) or the two-way interaction effects. Overall, using higher loads yielded higher RPEfatigue but lower REPfatigue, while RPEfatigue and REPfatigue were higher when slower velocities were used. Conclusion: The current investigation shows that not only load but also velocity and barbell load distribution may influence bench press training volume and perceived exertion. [ABSTRACT FROM AUTHOR]

Problem Statement: During ultra-endurance races, given the long duration of the competitions, athletes can experience variations in body composition and moods. These elements can greatly affect the athlete's performance. Purpose: To evaluate the effects of an ultra-endurance race (4 consecutive Everesting Bike Challenges) on the body composition and moods of an adult athlete. Material and Methods: A well-trained amateur cyclist (male; 46 years; 64 kg; 1.69 cm; BMI 22.4 kg/m2) was monitored during the 4 Everesting Bike Challenges. This test is an ultra-endurance challenge that involves overcoming 8848 meters by climbing a single peak several times. The changes in body composition and hydration, calculated by bio-impedentiometry, and the changes in moods, obtained by administering the Profile of Mood States (POMS), in addition to Rating of Perceived Exertion (RPE) and Visual Analogic Scale, were measured at the beginning, during or at the end of each Everesting passed. Results: The resting heart rate was 42 beats per minute. The estimated theoretical maximal heart rate was 174 bpm. The monitored athlete overcame the 4 Everesting Bike Challenges covering a total of 904.79 km. The time taken to complete the race was 113 hours and 18 minutes. The total height difference exceeded was 35395 m. During the race the athlete pedaled with an average heart rate of 97 bpm. Body mass dropped from 64.0 to 63.1 kg between the start and end of the test. Wide variations in the athlete's Vigor (T0=16:T5=6), fatigue (T0=0:T5=6) and Sleep quality (T0=100:T5= ≈0) were found during the competition. Regarding the Rating of Perceived Exertion scale, the results obtained indicate a medium-low value (RP=3). Conclusion: The results of this study showed negligible reduction in body mass in the athlete who performed an ultra-endurance challenge. During and at the end of the climbing challenge, a significant reduction in Vigor and an important increase in Fatigue levels was highlighted, as well as a very evident reduction in Sleep quality. From the analysis of the RPE scale, medium-low values emerge at the end of each EBC. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Introduction: According to current guidelines, the intensity of health-enhancing aerobic exercise should be prescribed using a percentage of heart rate reserve (%HRR), which is considered to be more closely associated (showing a 1:1 relation) with the percentage of oxygen uptake reserve (% V˙ O2R) rather than with the percentage of maximal oxygen uptake (% V˙ O2max) during incremental exercise. However, the associations between %HRR and % V˙ O2R and between %HRR and % V˙ O2max are under debate; hence, their actual relationships were investigated in this study. Methods: Data from each stage of a maximal incremental exercise test performed by 737 healthy and physically inactive participants of the HERITAGE Family Study were screened and filtered then used to calculate the individual linear regressions between %HRR and either % V˙ O2R or % V˙ O2max. For each relationship, the mean slope and intercept of the individual linear regression were compared with 1 and 0 (i.e., the identity line), respectively, using one-sample t -tests. The individual root mean square errors of the actual versus the 1:1 predicted %HRR were calculated for both relationships and compared using a paired-sample t -test. Results: The mean slopes (%HRR–% V˙ O2R, 0.972 ± 0.189; %HRR–% V˙ O2max, 1.096 ± 0.216) and intercepts (%HRR–% V˙ O2R, 8.855 ± 16.022; %HRR–% V˙ O2max, −3.616 ± 18.993) of both relationships were significantly different from 1 and 0, respectively, with high interindividual variability. The average root mean square errors were high and revealed that the %HRR–% V˙ O2max relationship was more similar to the identity line (P < 0.001) than the %HRR–% V˙ O2R relationship (7.78% ± 4.49% vs 9.25% ± 5.54%). Conclusions: Because both relationships are different from the identity line and using a single equation may not be appropriate to predict exercise intensity at the individual level, a rethinking of the relationships between the intensity variables may be necessary to ensure that the most suitable health-enhancing aerobic exercise intensity is prescribed. [ABSTRACT FROM AUTHOR]

The effects of exercise training have never been investigated in centenarians. This single-subject research study aimed to assess the effects of a structured training protocol on functional capacities in a centenarian master athlete. A 99.5 years old male subject participated in the study. Before and after a 16-month training intervention the participant underwent a test battery for flexibility (YMCA sit and reach), balance (single leg stance), upper limb strength (hand grip and pinch strength), and lower limb power (counter movement jump) and muscular endurance (horizontal leg press with 85 kg load). After training, sit and reach (-3 cm) and counter movement jump (- 0.5 cm) scores decreased, whereas single leg stance (+1.3 s), left hand grip (+2.0 kg), right hand pinch (+ 0.5 kg), and horizontal leg press (+2 repetitions) scores increased. Right hand grip strength and left-hand pinch strength did not change after training. When pre- and post-training scores were compared to gender-matched normative values, flexibility resulted well below average, maybe because of a relatively broad age category (> 65 years). When more specific age categories were available, the participant's balance resulted slightly below average (age category 80-99 years) and upper limb strength above average (age category > 85 years). No normative values were found for lower limb power and muscular endurance. In conclusion, this study highlights that structured exercise training may play a role in maintaining -- and even in increasing -- functional capacities in the oldest old age. [ABSTRACT FROM AUTHOR]

Slackline has been proposed as a challenging and motivating tool for balance training. However, the transferability of balance performances among different balance tasks has been questioned. This study aimed to assess if slackline training affects dynamic and static balance performances on stable and unstable surfaces. Eighteen healthy males (8 to 14 years) were randomly assigned to an experimental or control group. For six weeks, both groups performed several supervised sports activities (2-hour sessions, 3 sessions per week). Additionally, the experimental group underwent a slackline-based balance training (1-hour sessions, 3 sessions per week). The dynamic and static balance were tested before and after the interventions using the Bass test (BASS) and the Stork stand test (SST), respectively. Landing (BASSlanding) and balance (BASSbalance) components of the dynamic balance were evaluated, while the static balance was assessed with eyes open (SSTopen) and closed (SSTclosed) on a stable surface, and with eyes open on an air cushion (SSTac). Two-way mixed-design ANOVAs revealed no interaction effect between time and group allocation in BASSlanding (p = .791), BASSbalance (p = .641), and right leg SSTopen (p = .177), SSTclosed (p = .076) and SSTac (p = .039), and left leg SSTopen (p = .100) and SSTclosed (p = .032). There was a significant interaction on left leg SSTac (p = .004), showing higher improvements over time in the experimental (mean improvement = 4.5 seconds, p < .001) compared to the control group (mean improvement = 0.9 seconds, p = .236). In conclusion, slackline balance training yielded no or negligible improvements on dynamic balance performances, whereas the improvements seemed higher on static balance, especially when measured on an unstable surface. [ABSTRACT FROM AUTHOR]

Problem Statement: Physical activity levels have been positively associated with mental and physical wellbeing. Nevertheless, associations between physical activity levels, which decrease with aging, and body image perception and indices of psycho-physical well-being have never been studied in adult and elderly subjects as a function of aging. Approach: This observational study was carried out in several provinces and regions of Italy. Information was collected from 192 men and 260 women between 50 and 98 years using a questionnaire on place of residence, physical activity level, perceived well-being and body image. Purpose: This study aimed to assess the influence of the level of physical activity on perceptions of body image and well-being in adult and elderly subjects. Results: Physical activity levels were positively associated with body image perception. Interactions between physical activity levels and the other investigated variables showed no significant effect on body image. Hence, the main effect of physical activity on body image does not vary according to the subject's age, place of residence (rural or urban), kind of job (active or sedentary) or educational level. The well-being index was not significantly associated with either physical activity levels or the other variables investigated in this study. Conclusions: Physical activity levels are positively correlated with the body image perception, and high levels of physical activity are associated with more accurate perceptions of body image. The effect of physical activity is not influenced by different individual characteristics; hence, increasing levels of physical activity could improve body image perception across a broad range of subjects. On the other hand, the well-being index was not influenced by either physical activity levels or the other characteristics examined in this investigation. Additional experimental studies are needed to develop a specific intervention to improve the well-being and body image perception in adults and elderly subjects. [ABSTRACT FROM AUTHOR]

Growing evidence points to the effectiveness of flywheel (FW) based iso-inertial resistance training in improving physical performance capacities. However, molecular adaptations induced by FW exercises are largely unknown. Eight resistance-trained men performed 5 sets of 10 maximal squats on a FW device. Muscle biopsies (fine needle aspiration technique) and blood samples were collected before (t0), and 2 h (t1) after FW exercise. Blood samples were additionally drawn after 24 h (t2) and 48 h (t3). Paired samples t -tests revealed significant increases, at t1, of mRNA expression of the genes involved in inflammation, in both muscle (MCP-1, TNF- α , IL-6) and peripheral blood mononuclear cells (IkB- α , MCP-1). Circulating extracellular vesicles (EVs) and EV-encapsulated miRNA levels (miR-206, miR-146a) significantly increased at t1 as well. Conversely, muscle mRNA level of genes associated with muscle growth/remodeling (IGF-1Ea, cyclin D1, myogenin) decreased at t1. One-way repeated measure ANOVAs, with Bonferroni corrected post-hoc pairwise comparisons, revealed significant increases in plasma concentrations of IL-6 (t1; t2; t3) and muscle creatine kinase (t1; t2), while IGF-1 significantly increased at t2 only. Our findings show that, even in experienced resistance trained individuals, a single FW training session modifies local and systemic markers involved in late structural remodeling and functional adaptation of skeletal muscle. [ABSTRACT FROM AUTHOR]

Menopause is an age-dependent physiological condition associated with a natural decline in oestrogen levels, which causes a progressive decrease of muscle mass and strength and bone density. Sarcopenia and osteoporosis often coexist in elderly people, with a prevalence of the latter in elderly women. The profound interaction between muscle and bone induces a negative resonance between the two tissues affected by these disorders worsening the quality of life in the postmenopausal period. It has been estimated that at least 1 in 3 women over age 50 will experience osteoporotic fractures, often requiring hospitalisation and long-term care, causing a large financial burden to health insurance systems. Hormonal replacement therapy is effective in osteoporosis prevention, but concerns have been raised with regard to its safety. On the whole, the increase in life expectancy for postmenopausal women along with the need to improve their quality of life makes it necessary to develop specific and safe therapeutic strategies, alternative to hormonal replacement therapy, targeting both sarcopenia and osteoporosis progression. This review will examine the rationale and the effects of dietary protein, vitamin D and calcium supplementation combined with a specifically-designed exercise training prescription as a strategy to counteract these postmenopausal-associated disorders. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the age-related alterations in the ability to exert maximal and to sustain submaximal isometric muscle torques after a fatiguing concentric exercise conducted with knee extensor (KE) and flexor (KF) muscles. Sixteen young (aged 19–30 years; 8 women) and 17 older (aged 65–75 years; 9 women) volunteers participated. The following tasks were performed before and immediately after 22 maximal concentric efforts of the right KE and KF at 1.05 rad/s: (1) a maximal voluntary isometric contraction (MVIC) task involving both KE and KF; and (2) a KE torque-steadiness task at a submaximal target contraction intensity (20% MVIC). During the dynamometric tests, surface EMG was recorded simultaneously from the KE and KF muscles. Fatigue-induced reductions in knee extension MVIC were similar (~15%) between groups, but young participants showed more pronounced declines in agonist (i.e. quadriceps) EMG responses in both time (RMS amplitude; ~15% vs. ~10%, p < 0.001) and frequency (median frequency; ~14% vs. ~8%, p < 0.01) domains. Torque steadiness exhibited a similar post-fatigue decrease in the two age groups (p < 0.01), but interestingly agonist activation (~17%; p < 0.001) and antagonist (i.e. hamstrings) co-activation (~16%; p < 0.001) declined only in the older participants. These findings suggest that the fatiguing concentric KE and KF exercise results in similar relative reductions (%) in maximal torque and steadiness of the KE in young and older individuals, but they are sustained by different age-related neuromuscular strategies. • Older adults are weaker and less steady than young adults. • Young and older adults show a similar post-fatigue loss of maximal muscle strength. • Fatigue-induced neuromuscular changes are different in young and older adults. [ABSTRACT FROM AUTHOR]