Isometric Handgrip Strength Research Articles

Time-of-day effects on physical performance and perceptual responses in Brazilian Jiu-Jitsu athletes

ABSTRACT This study investigated how the time of day affects physical performance and perceptual responses in Brazilian Jiu-Jitsu (BJJ) athletes. Given the significance of circadian rhythms on athletic capabilities, we aimed to determine whether performance variations occur across different times of the day (morning, 10:00–11:00h; afternoon, 14:00–15:00h; and evening, 18:00–19:00h) and if these effects differ by sex. In total, 23 BJJ athletes (9 females, 14 males) participated in this study. The athletes performed physical tests including the maximal isometric handgrip strength test (HGS), Kimono Grip Strength Endurance Test (KGST), and a BJJ-specific test (BJJST) in the morning, afternoon, and evening. Perceptual responses (RPE) were also collected before the BJJST. Results showed enhanced physical performance in the evening for most tests, including increased HGS and superior performance in the KGST and BJJST for both sexes (p < 0.05). No significant differences were observed in perceptual responses (RPE) or between sexes (p > 0.05). We conclude that BJJ athletes generally perform better in the evening compared to other times of the day, with notable improvements in HSG and specific BJJ tests. The study highlights the importance of aligning training schedules with an athlete’s circadian rhythm to optimize performance, leading to more efficient training sessions and improved long-term performance outcomes.

Cross-sectional associations between dietary intake of polyunsaturated fatty acids, physical function, and sarcopenia in community-dwelling older adults

ObjectivesThe present study examined the associations between the dietary intake of polyunsaturated fatty acids (PUFAs), physical function, and the prevalence of sarcopenia in Italian community-dwelling older adults. DesignCross-sectional study. SettingUnconventional settings across Italy (e.g., exhibitions, health promotion campaigns). ParticipantsOlder adults (65+ years) who provided a written informed consent. MethodsPhysical function was evaluated according to isometric handgrip strength (IHG) and 5-time sit-to-stand (5STS) performances. Muscle power parameters were estimated based on 5STS values. Sarcopenia was operationalized according to the presence of low physical function (IHG or 5STS) plus low appendicular skeletal muscle mass (ASM), estimated according to calf circumference. A 12-item food questionary was used to estimate the dietary intake of PUFAs, which included omega-3 (α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid) and omega-6 fatty acids. ResultsMultiple linear regression results indicate negative and significant associations between the dietary intake of α-linolenic acid and muscle power, and between docosahexaenoic acid consumption and ASM. No significant associations were found between PUFAs-related variables and sarcopenia. ConclusionsResults of the present study indicate that PUFAs-related variables were negatively and significantly associated with physical function and body composition in older adults. Nevertheless, no significant associations were found with sarcopenia. These findings suggest that a more detailed analysis of covariates should be conducted in future investigations that aim to examine the associations between the dietary intake of PUFAs and sarcopenia-related parameters.

Adapted Taekwondo Improves Postural Balance and Health-Related Quality of Life Concerning Multicomponent Training and Walking Exercise in Older Females: A Randomized Controlled Trial (TKD and Aging Project).

Background/Objectives: This study aimed to assess and compare the effects of an adapted taekwondo (TKD) program, multicomponent training (MCT), walking exercise (WE), and inactive control group (CG) on blood pressure, morphological variables, frequency of food consumption, cognitive status, health-related quality of life (HRQoL), physical fitness tests, and postural balance in independent older females. Methods: A randomized controlled trial study was conducted with the following groups: TKD (n = 13), MCT (n = 12), WE (n = 12), and CG (n = 14), considering three/weekly 60-min/sessions for 16-weeks. A two-factor mixed analysis of the variance model with repeated measures was performed. Results: TKD improved significantly more in phonetic fluency (p = 0.021; ES = 1.89) than WE and in general health (p = 0.033; ES = 1.11) than CG. Both TKD and MCT improved significantly more than CG in the 30 s chair stand, arm curl, chair sit-and-reach, timed up-and-go, maximal isometric handgrip strength, and postural balance for the eyes closed condition in the area and anteroposterior velocity (p < 0.05). Conclusions: Only TKD improved the area (p = 0.008; ES = 1.00) and mediolateral velocity (p = 0.019; ES = 0.79) for the eyes open condition, and mediolateral velocity (p = 0.021; ES = 1.57) for the eyes closed condition. Blood pressure, morphological variables, and food consumption frequency showed no significant intragroup or intergroup interactions. TKD equivalently improved HRQoL and physical fitness to MCT, with better postural balance in older females.

Comparison Of Isometric Hand Grip Strength Among Computer Users and Non- Computer Users and Its Relation with The Incidence of Neck Pain. A Correlational Study

Comparison Of Isometric Hand Grip Strength Among Computer Users and Non- Computer Users and Its Relation with The Incidence of Neck Pain. A Correlational Study

Effects of a 4-Week Detraining Period After 12 Weeks of Combined Training Using Different Weekly Frequencies on Health-Related Physical Fitness in Older Adults.

Detraining refers to the decline in physical fitness that occurs after the cessation of exercise, compromising the adaptations resulting from regular exercise training. To understand how long the benefits acquired from an exercise program can be maintained, the present study evaluated the detraining effects of a 4-week exercise cessation period in older adults who performed combined training at various weekly frequencies for 12 weeks. This randomized controlled trial assigned participants to one of two training programs: a combined training program twice a week (CT2) or four times a week (CT4) over a period of 12 weeks, followed by a four-week detraining period. The resistance training consisted of six bodyweight exercises, while the aerobic training involved either walking or running. Both the CT2 and CT4 groups completed the same total training volume and overload each week; the only difference was the number of training sessions per week. Assessments were conducted at baseline, after the training period, and after the detraining period, and included the 30-s and five-repetition chair-stand tests, isometric handgrip strength, body mass index (BMI), waist circumference, and waist-to-height ratio. Thirty-one participants completed the study (CT2: 17 and CT4: 14). The groups presented similar attendance records during the training period (CT2: 96 ± 18% versus CT4: 94 ± 19%). After the 12-week training period, CT2 and CT4 improved lower limb strength, CT2 improved upper limb strength, and CT4 reduced waist circumference and waist-to-height ratio compared to baseline. After the 4-week detraining period, the lower limb strength remained improved in both groups (CT2: 4 ± 1 repetition; p < 0.001 and CT4: 4 ± 1 repetition; p < 0.001) when compared to the corresponding baseline values. The handgrip strength decreased in CT2 compared to post-training values. And the body composition benefit in CT4 was not sustained after detraining. The effects of 4 weeks of detraining after 12 weeks of training performed two or four times per week are similar on some but not all health-related physical fitness parameters.

Grip to Health: Unlocking the Clinical Potential of Isometric Hand Grip Strength - A Narrative Review

Grip to Health: Unlocking the Clinical Potential of Isometric Hand Grip Strength - A Narrative Review

Hand grip strength in older and very old people: Results of the study Gesundheit 65+

Abstract Background Functional capacity decreases with increasing age. Hand grip strength (HGS) is considered as an objective general measure of health and a parameter of muscle strength, a component of functional capacity and is part of the evaluation of frailty. HGS is important for many everyday functions, such as holding heavy objects or supporting oneself to prevent a fall. Low HGS is associated with a higher mortality risk. In our study we describe HGS in people aged 66 to 101 years in Germany and identify groups with low HGS. Methods Gesundheit 65+ is a longitudinal epidemiologic study of the health status of persons 65 years and older in Germany by the Robert Koch Institute. In 2022/23, one year after baseline, isometric HGS was measured during the examination part of the study using a hand-held dynamometer (Smedley, Scandidact, Denmark, 100 kg). Two values were recorded for each hand. Maximum HGS from all attempts was used for analyses. Weighted prevalence estimates and 95% confidence interval (CI) for grip strength are reported by sex, age-group, height, self-rated health, chronic conditions, and difficulties in activities of daily living (ADL). Results HGS was measured in 1,457 persons aged 66 to 101 (48% women). Mean maximum HGS was 28.8 kg (CI 28.4-29.3). HGS was significantly related to sex (men: 35.4 kg, CI 34.8-36.0, women 21.8 kg, CI 21.4-22.2) and age (66-79: 31.0 kg, CI 30.1-31.9, 80+: 23.9 kg, CI 23.0-24.7). In both sexes, shorter persons and persons with bad self-rated health, chronic conditions or difficulties in ADL showed lower HGS than their reference group. Conclusions HGS was reduced in very old people, people with support needs, and people with poor health or chronic diseases, identifying these people as important risk groups for preventive measures. These should aim to improve not only endurance but also strength in older and very old people. In the long term, this could also maintain independence and reduce serious injuries from falls. Key messages • We found sex and age-related differences in hand grip strength in older people in Germany. • Based on the results, planning of prevention and intervention could be enhanced.

Physiological Response and Sports Injury Risk Relevant Biomechanics in Endurance Obstacle Course Races

Obstacle course races (OCR) have experienced significant growth in recent years, with millions of participants worldwide. However, there is limited research on the specific physiological demands and injury prevention strategies required for these events. This study aimed to analyze the physiological responses and injury risks in participants of a 5 km (Sprint) and 13 km (Super) OCR. Sixty-eight participants were assessed for cortical arousal, leg strength, isometric handgrip strength, blood lactate, heart rate, blood oxygen saturation, body temperature, urine composition, spirometry values, hamstring flexibility, lower limb stability, foot biomechanics, and scapular kinematics, one hour before and immediately after the races. The results showed a significant decrease in leg strength (Sprint: r = −0.56, p &lt; 0.01; Super: r = −0.54, p = 0.01) and urine pH (Sprint: r = −0.70, p = 0.03; Super: r = −0.67, p = 0.01) in both distances, with increases in urine colour, protein, and glucose (Sprint: p &lt; 0.04). In the 13 km race, lower limb stability decreased significantly post-race (r = −0.53, p = 0.01). Positive correlations were found between performance and pre-race handgrip strength (Sprint: r = 0.71, p = 0.001; Super: r = 0.72, p = 0.01) and spirometry values (FVC, FEF 25–75%, FEV1) (Sprint: r = 0.52, p = 0.031; Super: r = 0.48, p = 0.035). Thermoregulation capacity, reflected in a higher pre-race body temperature and lower post-race body temperature, also correlated with improved performance (r = 0.49, p = 0.046). Injury risk increased post-race, with a significant decline in lower limb stability (p &lt; 0.05). These findings highlight the importance of targeted training programs, focusing on grip strength, leg strength, respiratory muscle training, and hydration strategies to optimize performance and reduce injury risk in OCR athletes.

Effects of Successive Annual Training on Young Swimmers’ Strength Asymmetries and Performance

This study aimed to compare changes in swimmers’ performance, biomechanical variables, and strength asymmetries within two successive training years. Eight competitive age-group swimmers (four males and four females; age: 14.8 ± 1.3 years) were tested before and after the same 12-week mesocycle period within two successive years (Year-1, Year-2). The swimmers were timed in 50, 200, and 400 m, and the stroke rate (SR), stroke length (SL), and stroke index (SI) were calculated. SI was calculated by the product of SL with swimming speed. Dryland shoulder isometric strength (ISO), hand grip isometric strength test (HG), and in-water maximum 30 s tethered swimming force (TF) were evaluated. The asymmetry index was calculated using ISO, HG, and TF tests as [(Fd − Fnd)/0.5 × (Fd + Fnd)] × 100, where Fd is strength in the dominant hand and Fnd is strength in the non-dominant hand. Performance time improved in 200 and 400 m, while the asymmetry indices calculated by the ISO, HG, and TF tests were similar after 12 weeks of training in both Year-1 and Year-2 (p = 0.01). Changes (Δ) in HG strength asymmetries correlated with Δ in 200 and 400 m in Year-2 (r = 0.78–0.87, p = 0.01). The asymmetry index does not change after two successive years of training but may be connected to performance changes in 200 and 400 m front crawl.

Impact of Multi-Professional Intervention on Health-Related Physical Fitness and Biomarkers in Overweight COVID-19 Survivors for 8 and 16 Weeks: A Non-Randomized Clinical Trial.

Considering the diverse symptomatology of COVID-19-ranging from mild to severe cases-multi-professional interventions are crucial for enhancing physical recovery, nutritional status, and mental health outcomes in affected patients. Thus, this study aimed to investigate the effects of such an intervention on health-related physical fitness and biomarkers in overweight COVID-19 survivors with varying degrees of symptom severity after 8 weeks and 16 weeks. This non-randomized clinical trial included 59 overweight COVID-19 survivors (32 males and 27 females) divided into three groups: mild (n = 31), moderate (n = 13), and severe/critical (n = 15). The participants underwent a multi-professional program and were assessed for anthropometric and body composition (primary outcome), as well as physical fitness and biochemical markers (secondary outcome) 8 and 16 weeks before the intervention. After 8 weeks, time effects were observed for the maximum isometric handgrip strength (p < 0.001), maximum isometric lumbar-traction strength (p = 0.01), flexibility (p < 0.001), abdominal strength-endurance (p < 0.001), the sit-and-stand test (p < 0.001), maximum oxygen consumption (p < 0.001), and distance covered in the 6 min walk test (p < 0.001). Additionally, time effects were also observed for fat mass (p = 0.03), body fat percentage (p = 0.02), abdominal circumference (p = 0.01), total cholesterol (p < 0.001), low-density lipoproteins (p < 0.001), and glycated hemoglobin (p < 0.001), with lower values after multi-professional interventions. After 16 weeks, the systolic and diastolic blood pressure showed significant reductions independently of the intervention group (p < 0.001). These findings suggest that multi-professional interventions can provide substantial benefits for post-COVID-19 patients, regardless of the severity of their initial symptoms.

Longitudinal Assessment Of Handgrip Isometric Strength During Childhood

Longitudinal Assessment Of Handgrip Isometric Strength During Childhood

Physical, functional and personal variables affecting shoulder complaints in healthcare workers.

Work-related shoulder disorders adversely affect the quality of life and lead to increased costs related to decreased productivity and injury treatment. Therefore, understanding the relationship between strength, upper extremity function and work ability contributes to the development of interventions aimed to improve the well-being of healthcare workers. Correlate shoulder abduction and handgrip strength with upper extremity function and work ability in healthcare workers with shoulder complaints. 67 workers with shoulder pain in the last year were assessed by Disability of Arm, Shoulder and Hand (QuickDASH), Work Ability Index (WAI), isokinetic shoulder strength and isometric handgrip strength dynamometers. Data were analysed with Spearman's Correlation Coefficient (ρ= 0.05), SPSS 20.0®. 52% males, mean age 48.4 years, 42% physically active, most administrative and general services workers. Low correlation between handgrip strength and QuickDASH (r=-0.359; p = 0.004); low correlation between handgrip strength and WAI (r = 0.359; p = 0.003) and between shoulder abduction strength and the QuickDASH (r = -0.267; p = 0.049); no significant correlation between shoulder abduction strength and WAI (r = 0.001; p = 0.997). Handgrip and shoulder abduction strength were inversely associated with upper extremity dysfunction. Shoulder abduction strength was associated with work ability. The inclusion of strength assessment in workers is important to guide strategies to prevent musculoskeletal disorders.

Xbox Kinect Sports vs. Nintendo Switch Sports and Their Effects on Body Composition and Physical Performance in Older Females: A Randomized Controlled Trial.

Background/Objectives: This study aimed to compare the effects of Xbox Kinect Sports (XKS) regarding Nintendo Switch Sports (NSS) and an inactive control group (CG) on body composition (body fat percentage, BFP; and fat-free mass) and physical performance (maximal isometric handgrip strength, MIHS; 30-s chair stand, 30-S; timed up-and-go, TUG; sit-and-reach; and 2-min step) in physically inactive older females. Methods: A randomized controlled trial study was conducted with three parallel groups: XKS (n = 13), NSS (n = 14), and CG (n = 16) considering three weekly 60-min sessions for 12 weeks with pre- and post-assessments. Results: A two-factor mixed analysis of variance (ANOVA) model with repeated measures was performed to measure the time × group effect. Multiple comparisons revealed significant differences in BFP (F(2,18) = 6.12; p = 0.005; ηp2 = 0.226, large effect), 30-S (F(2,18) = 20.7; p = 0.000; ηp2 = 0.496, large effect), TUG (F(2,18) = 10.0; p = 0.000; ηp2 = 0.323, large effect), sit-and-reach (F(2,18) = 37.3; p = 0.000; ηp2 = 0.640, large effect), and 2-min step (F(2,18) = 9.85; p = 0.000; ηp2 = 0.319, large effect) in favor of XKS regarding NSS and CG. The intragroup results only present in XKS a significant decrease in BFP (p = 0.02; d = 0.98) and significant improvements in the 30-S (p = 0.000; d = 1.88), TUG (p < 0.01; d = 2.00), sit-and-reach (p = 0.003; d = 2.58), and 2-min step (p = 0.004; d = 1.05). Conclusions: training using XKS significantly decreases BFP and improves 30-S, TUG, sit-and-reach, and 2-min step in physically inactive older females.

Psychometric properties of the modified reaching performance scale in persons with multiple sclerosis

BackgroundA valid and reliable assessment tool to describe the quality of the movement pattern of reaching can provide valuable insights into motor performance deficits in persons with MS (pwMS). The Reaching Performance Scale, developed for stroke, is a promising scale to assess movement patterns in pwMS. However, psychometric properties of the scale are lacking in pwMS. ObjectivesFirstly, to investigate the content validity of the modified Reaching Performance Scale for application in patients with MS (mRPS). Secondly, to investigate the psychometric properties (within- and between-session reliability and concurrent validity) of the mRPS for pwMS. MethodsForty-five pwMS (mean EDSS 6.6 pt, IQR 6–7.5) executed the mRPS that rates the quality of movement patterns and compensations during reach to grasp tasks. The content validity was determined by an expert panel based on observations of subjects performing the RPS. The reliability was based on five repetitions within one day, and between two days. For the concurrent validity, outcome measures at two levels of the International Classification of Functioning were correlated with the mRPS: Body Structure and Function level: Fugl-Meyer Assessment of the Upper Limb (FMA-UL), maximal isometric hand grip strength (HGS; Activity level: Action Research Arm Test (ARAT), Box and Blocks Test (BBT), Nine Hole Peg Test (NHPT) and Trunk Impairment Scale 2.0 (TIS 2.0) as well as perceived performance by the Manual Ability Measure-36 (MAM-36). ResultsScale modifications were made only on the ratings of the trunk displacement subscale. The mRPS had excellent agreement scores for within-session reliability (range of Kappa between 0.85 and 0.98) and moderate-to-excellent agreement scores for between-session reliability (K: 0.66–1.00). Regarding validity, the mRPS was highly correlated with the ARAT (rho=0.74, p < 0.001), followed by moderate correlations with trunk performance (TIS 2.0, rho= 0.61, p < 0.001), hand function (BBT: rho=0.64, p < 0.001; NHPT: rho=-0.61, p < 0.001) and perceived performance (MAM36 rho= 0.53, p < 0.001). ConclusionThe mRPS is a reliable measurement tool to describe the movement pattern quality and motor compensations used during reaching in pwMS. Concerning concurrent validity, the mRPS is partially related to other measures of upper limb and trunk performance.

Tournament Recovery Profiles and Physical Demands in a Collegiate Women's Tennis Team.

Tendero-Ortiz, E, Johnson, MJ, Horsfall, CM, Vondrasek, JD, Grosicki, GJ, Riemann, BL, and Flatt, AA. Tournament recovery profiles and physical demands in a collegiate women's tennis team. J Strength Cond Res XX(X): 000-000, 2024-We aimed to characterize recovery profiles and tournament physical demands in women's collegiate tennis players. A Division 1 team (n = 9) participated in the study. Markers of cardiac autonomic (resting heart rate [HR], HR variability), neuromuscular (isometric handgrip strength, seated single-arm shot-put test [SSAPT], hexagon agility, countermovement jump characteristics), and perceptual recovery were obtained before the tournament (baseline) and again 1 and 2 days posttournament. Cardiorespiratory (HR) and movement characteristics from matches were quantified with wearable devices. p values < 0.05 were statistically significant. No recovery markers differed from baseline (ps > 0.05), although small effect size reductions 1 day posttournament were noted for SSAPT, hexagon agility, and select countermovement jump characteristics. In addition, hexagon agility times and SSAPT were slower (p < 0.01) and shorter (p < 0.05), respectively, at 1 versus 2 days posttournament. Similarly, relative to 1 day posttournament, perceptual makers were improved 2 days posttournament (ps < 0.05). Mean and peak HR were higher for singles versus doubles matches (ps < 0.05). Except for average speed, movement parameters were greater during singles versus doubles matches (ps < 0.05). Markers of recovery were minimally affected 1 day posttournament relative to baseline, but perceptual and select neuromuscular markers were most improved 2 days posttournament. Thus, passive rest or limited intensity training 1 day posttournament seems advisable. Competition HR and movement profiles inform practitioners of the cardiorespiratory and locomotor demands of women's collegiate tennis, which may be useful in designing preparatory conditioning programs to ensure that players attain match-specific physical capacities in training before competition.

Establishment of regression-based isometric strength reference values for the upper limb in persons with multiple sclerosis.

Muscle weakness is common and significantly affects persons with multiple sclerosis (PwMS), with dysfunction in upper limb (UL) muscle groups occurring in approximately 60% of PwMS. To develop gender-specific regression-based prediction equations, with 95% confidence intervals for maximal bilateral UL isometric strength (shoulder abduction and adduction, wrist flexion and extension) and hand grip strength in PwMS. Cross-sectional study. Comprehensive MS center. 256 PwMS. Not Applicable. Shoulder abduction and adduction and wrist flexion and extension isometric strength(Biodex System 4 Pro Dynamometer) and hand grip strength (Jamar handheld dynamometer) were measured. Disease characteristics (disability and disease duration) and demographics (age, height, and weight) were collected. Regression-based predictive equations were generated for the UL muscle groups for each gender and limb, using age, height, weight, disability, and disease duration as covariates. Variables were compared between genders using the Mann-Whitney U test. Maximal voluntary contraction (MVC) reference values (mean ± SD) were reported based on age (<30, 30-39, 40-49, 50-59, 60-69 years) and disability (mild, moderate, severe ambulant, and severe nonambulant) for each gender and limb. Regression-based equations were developed for both genders' strongest and weakest limb, accounting for age, height, weight, disability, and disease duration. MVC was higher in men than women (p < .001) in all muscle groups. Overall, MVC was significantly related to age in 14, height in 5, weight in 6, disability in 14, and disease duration in none of the 20 models. This is the first study to provide regression-based prediction equations for strongest and weakest MVC of UL muscle groups and demonstrated an inverse relationship between MVC with disability and age. Regression-based reference strength values can help clinicians understand muscular strength along a spectrum of PwMS and can aid in goal setting and education for realistic outcomes.

Effect of resistance training on physical function during chemotherapy in colon cancer.

The decline of physical function during chemotherapy predicts poor quality of life and premature death. It is unknown if resistance training prevents physical function decline during chemotherapy in colon cancer survivors. This multicenter trial randomly assigned 181 colon cancer survivors receiving postoperative chemotherapy to home-based resistance training or usual care control. Physical function outcomes included the short physical performance battery, isometric handgrip strength, and the physical function subscale of the Medical Outcomes Short-Form 36-item questionnaire. Mixed models for repeated measures quantified estimated treatment differences. At baseline, participants had a mean (SD) age of 55.2 (12.8) years; 67 (37%) were 60 years or older, and 29 (16%) had a composite short physical performance battery score of no more than 9. Compared with usual care control, resistance training did not improve the composite short physical performance battery score (estimated treatment difference = -0.01, 95% confidence interval [CI] = -0.32 to 0.31; P = .98) or the short physical performance battery scores for balance (estimated treatment difference = 0.01, 95% CI = -0.10 to 0.11; P = .93), gait speed (estimated treatment difference = 0.08, 95% CI = -0.06 to 0.22; P = .28), and sit-to-stand (estimated treatment difference = -0.08, 95% CI = -0.29 to 0.13; P = .46). Compared with usual care control, resistance training did not improve isometric handgrip strength (estimated treatment difference = 1.50 kg, 95% CI = -1.06 to 4.05; P = .25) or self-reported physical function (estimated treatment difference = -3.55, 95% CI = -10.03 to 2.94); P = .28). The baseline short physical performance battery balance score (r = 0.21, 95% CI = 0.07 to 0.35) and handgrip strength (r = 0.23, 95% CI = 0.09 to 0.36) correlated with chemotherapy relative dose intensity. Among colon cancer survivors with relatively high physical functioning, random assignment to home-based resistance training did not prevent physical function decline during chemotherapy. NCT03291951.

Five-Time Sit-To-Stand Lower Limb Muscle Power in Older Women: An Explorative, Descriptive and Comparative Analysis

BackgroundMuscle power assessment entails the use of complex equipment which impacts its clinical applicability. Recently, equations to estimate lower-limb muscle power measures based on 5-repetition sit-to-stand (5STS) performance and anthropometric parameters were validated. However, their ability to discriminate physical performance status in older adults is still unknown. Moreover, the analysis of the biomechanical aspects of 5STS might represent a valid instrument to identify people with different physical statuses.ObjectivesExplore and examine the biomechanical aspects of 5STS performance, and compare the capacity of this measure and 5STS muscle power equations to discriminate older women with different physical function levels.DesignCross-sectional study. Setting: Community. Participants: Older women. Measurements: 5STS using a linear encoder, Timed “Up-andGo” (TUG), isometric handgrip strength (IHG) and walking speed (WS).ResultsResults from ANOVA analysis indicated that peak concentric muscle power was reached in the first 5STS repetition and then declined significantly (P=0.006). When participants were divided in high and low physical performance groups according to median results of TUG, IHG and WS tests, significant differences in 5STS biomechanical aspects were observed, according to independent t-test results (P<0.05). However, no differences were found for 5STS muscle power equations. Pearson’s correlation analysis indicated that 5STS biomechanical aspects (P<0.05), but not 5STS muscle power equations, were significantly associated with physical performance.ConclusionFindings of the present study suggest that 5STS biomechanical aspects might contribute to discriminating older women with high and low physical performance.

Agreement and Associations between Countermovement Jump, 5-Time Sit-To-Stand, Lower-Limb Muscle Power Equations, and Physical Performance Tests in Community-Dwelling Older Adults.

Objectives: The present study examined the agreement and associations of the 5-time sit-to-stand (5STS) test, the countermovement jump test, and lower-limb muscle power equations with a set of physical performance tests in older adults. Methods: Five hundred and thirty-four community-dwelling older adults were recruited for the study. Lower-limb muscle power measures included 5STS, the countermovement jump test, and muscle power equations. Isometric handgrip strength, timed "up-and-go!", the 6 min walking test, one-leg stand, and walking speed at usual and fast paces were used to assess physical performance. Pearson's correlations and Bland-Altman analyses were conducted to examine associations among muscle power measures. Linear and multiple regressions were run to explore associations of 5STS, the countermovement jump test, and muscle power equations with physical performance tests. Results: Weak correlations were observed among lower-limb muscle power measures. Bland-Altman results indicated important differences among the countermovement jump test, 5STS, and muscle power equations. Results of multiple linear regressions indicated that 5STS, the countermovement jump test, and muscle power equations were significantly associated with measures of muscle strength and mobility. However, only 5STS was significantly associated with balance. Conclusions: Our results indicate that the performance on the countermovement jump test and 5STS is weakly correlated with lower-limb muscle power equations. The only exception was the correlation found between the countermovement jump test and relative muscle power, highlighting the importance of accounting for body mass in muscle power evaluations. Muscle power measures were similarly associated with performance on handgrip strength, timed "up-and-go!", and the 6 min walking test. The exclusive association of 5STS with balance suggests that a reassessment of 5STS muscle power equations may be warranted.

Resistance Training with Instability Does Not Hamper Total Training Volume and Muscle Strength Gains in Older Adults: a Secondary Analysis from REI Study.

Resistance training with instability (REI) emerged as a promising training modality for older adults aiming to counteract age-related changes. We compared the effects of 12 weeks of REI and traditional resistance exercise (RE) on muscle strength in older adults with cognitive impairment. We further explored if total training volume (TTV) significantly differs among training groups. This is a secondary analysis of the REI study. Participants were randomly assigned to REI (n=22) or RE (n=23). RE protocol involved moderate-intensity, free-weight, and machines-based resistance exercises (3 sets, 10-15 repetitions). REI received a similar training protocol, in which exercises were simultaneously performed with instability/unstable devices (e.g., squat exercise under a foam pad or Bosu® ball). Maximal isometric strength and isokinetic parameters were assessed at baseline and after completion of a 12-week intervention through a hydraulic handgrip and isokinetic dynamometer, respectively. TTV (sets × repetitions × load) was computed based on external training load over the 12 weeks. No differences were observed between groups (p=.35) after the intervention. Over 12 weeks, REI and RE improved isometric handgrip strength (p<.001) and isokinetic performance (p=.04). We also did not find differences in the TTV between training groups (p=.28). We demonstrated that both REI and RE training induced similar gains in muscle strength. Combining unstable surfaces/instability devices did not hamper TTV, which may have clinical applications in the context of exercise for older adults.