Maximal Isometric Handgrip Strength Research Articles

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.

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.

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.

Recovery markers in elite climbers after the national boulder climbing championship.

This study aimed to investigate recovery markers among elite climbers following the National Boulder Championship. We assessed maximum isometric hand grip strength (HS), forearm swelling (circumference), delayed soreness in forearm muscles, tiredness, and exercise readiness at several time points: pre-competition, immediately post-competition (within 4 min after their last effort), and 12, 24, 48, and 60 h post-competition. Maximum isometric hand grip strength decreased by 6.38 ± 1.32% (p = 0.006) post-12 h, returning to pre-competition values post-24 h (all p > 0.05). Forearm circumference (FC) increased 1.78 ± 1.77% (p < 0.001) post-competition, returning to pre-competition values post-12 h (all p > 0.05). Forearm pain (FP) increased post-competition (p = 0.002) and post-12 h (p < 0.001), returning to pre-competition values post-24 h (all p > 0.05). Tiredness increased post-competition (p < 0.001), post-12 h (p < 0.001), and post-24 h (p < 0.001), returning to pre-competition values post-48 h (all p > 0.05). Climbing readiness was reduced post-competition (p < 0.001), post-12 h (p < 0.001), post-24 h (p < 0.001), and post-48 h (p = 0.005), only returning to pre-competition values post-60 h (p = 0.189). Visual analysis of individual data pointed out a relatively small variability in the HS and FC markers, while FP, tiredness, and readiness exhibited larger individual variations. These findings indicate that different recovery patterns exist for the analyzed markers, suggesting that athletes may require up to 60 h after a competition to fully recover and regain their ability to face new competitive challenges.

An Assessment of Maximal Isometric Hand Grip Strength and Upper Body Explosive Strength and Endurance in Various Ball Sports

Background. Playing with the ball and using hand-arm strength and power are very crucial for ball game players. It takes arm force and endurance, as well as isometric hand grip strength, to accomplish ball-game skills. Study purpose. The aim of the study was to evaluate maximal isometric hand grip strength, arm and shoulder explosive strength, and endurance in basketball, handball, and volleyball athletes. Materials and methods. The study randomly selected 135 male athletes, including 45 basketball, 45 handball, and 45 volleyball players, aged 17 to 24, all competing at the inter-university level. Hand grip strength (HGS) for both dominant (DHGS) and non-dominant (NDHGS) hands was measured using a JAMAR hydraulic hand grip dynamometer. An over-the-head seated medicine ball throw (SMBT) test assessed explosive arm strength, while a push-up (PU) test evaluated muscular strength and endurance. Results. The F-values (F) (2, 132) of DHGS, NDHGS, SMBT, and PU tests among basketball, handball, and volleyball players were .499 (p = .608); 1.166 (p = .315); 5.595 (p = .005); and 10.339 (p = .000), respectively. The results indicated that no notable distinctions were observed in DHGS and NDHGS among athletes in the three sports. However, considerable differences were found in the SMBT and PU tests. Conclusions. The study concluded that basketball, handball, and volleyball players’ maximum isometric hand grip strength was nearly the same, but in both cases, the handball player's mean value was superior to others. Upper-body explosive power, muscular strength, and endurance showed distinct differences from one group to another.

Skin Bioimpedance Analysis to Determine Cellular Integrity by Phase Angle in Women with Fibromyalgia: A Cross-Sectional Study.

Oxidative stress has been proposed as a significant part of the pathogenesis of fibromyalgia, and the phase angle in bioelectrical impedance analysis has been explored as a potential technique to screen oxidative abnormalities. This study recruited 35 women with fibromyalgia and 35 healthy women, who underwent bioelectrical impedance analysis and maximum isometric handgrip strength tests. Women with fibromyalgia showed lower bilateral handgrip strength (right hand: 16.39 ± 5.87 vs. 27.53 ± 4.09, p < 0.001; left hand: 16.31 ± 5.51 vs. 27.61 ± 4.14, p < 0.001), as well as higher body fat mass (27.14 ± 10.21 vs. 19.94 ± 7.25, p = 0.002), body fat percentage (37.80 ± 8.32 vs. 30.63 ± 7.77, p < 0.001), and visceral fat area (136.76 ± 55.31 vs. 91.65 ± 42.04, p < 0.01) compared with healthy women. There was no statistically significant difference in muscle mass between groups, but women with fibromyalgia showed lower phase angles in all body regions when compared with healthy control women (right arm: 4.42 ± 0.51 vs. 4.97 ± 0.48, p < 0.01; left arm: 4.23 ± 0.48 vs. 4.78 ± 0.50, p < 0.001; trunk: 5.62 ± 0.77 vs. 6.78 ± 0.84, p < 0.001; right leg: 5.28 ± 0.56 vs. 5.81 ± 0.60, p < 0.001; left leg: 5.07 ± 0.51 vs. 5.69 ± 0.58, p < 0.001; whole body: 4.81 ± 0.47 vs. 5.39 ± 0.49, p < 0.001). Moreover, whole-body phase-angle reduction was only predicted by the presence of fibromyalgia (R2 = 0.264; β = 0.639; F(1,68) = 24.411; p < 0.001). Our study revealed significantly lower phase angle values, lower handgrip strength, and higher fat levels in women with fibromyalgia compared to healthy controls, which are data of clinical relevance when dealing with such patients.

Profiling the Physical Performance of Young Boxers with Unsupervised Machine Learning: A Cross-Sectional Study.

Mexico City is the location with the largest number of boxers in Mexico; in fact, it is the first city in the country to open a Technological Baccalaureate in Education and Sports Promotion with a pugilism orientation. This cross-sectional study aimed to determine the physical-functional profile of applicants for admission to the baccalaureate in sports. A total of 227 young athletes (44F; 183M; 15.65 (1.79) years; 63.66 (14.98) kg; >3 years of boxing experience) participated in this study. Body mass (BM), maximal isometric handgrip (HG) strength, the height of the countermovement jump (CMJ), the velocity of straight boxing punches (PV), and the rear hand punch impact force (PIF) were measured. The young boxers were profiled using unsupervised machine learning algorithms, and the probability of superiority (ρ) was calculated as the effect size of the differences. K-Medoids clustering resulted in two sex-independent significantly different groups: Profile 1 (n = 118) and Profile 2 (n = 109). Except for BM, Profile 2 was statistically higher (p < 0.001) with a clear distinction in terms of superiority on PIF (ρ = 0.118), the PIF-to-BM ratio (ρ = 0.017), the PIF-to-HG ratio (ρ = 0.079) and the PIF-to-BM+HG ratio (ρ = 0.008). In general, strength levels explained most of the data variation; therefore, it is reasonable to recommend the implementation of tests aimed at assessing the levels of isometric and applied strength in boxing gestures. The identification of these physical-functional profiles might help to differentiate training programs during sports specialization of young boxing athletes.

Influence of Successive Wheelchair Tennis Matches on Handgrip Strength in High-Level Male Players

The purpose of this study was to examine the effects on upper strength in high-level male players playing four successive wheelchair tennis (WT) matches. Eight international WT players took part in a competition, playing one match per day over four consecutive tournament days. Before and after the match, the maximal isometric handgrip strength was measured on the dominant and non-dominant hand. Additionally, each player was equipped with one radiofrequency and IMU device on their wheelchair to control his activity profile (distance). The results showed significant differences between successive matches, with decreasing dominant handgrip strength (p = 0.02, η2 = 0.043), and there was a significant interaction between successive matches and the accumulated distance (p = 0.013, η2 = 0.049). The pre- and post-match strength values of the dominant hand decreased throughout the matches over a number of days, and post hoc analysis showed differences between the first and fourth matches only in pre-match strength (49.06 ± 6.96 vs. 45.94 ± 7.1; p = 0.045; ES: 1.04) but not in the non-dominant hand. Successive matches caused a decrease in the strength values of the WT players, mainly in the dominant hand. These results should be taken into account in the recovery and prevention of injuries in competitions with successive matches.

Correlation of the Handgrip Strength and Body Composition Parameters in Young Judokas.

Maximum isometric handgrip strength (MIHS) is a relevant parameter for judo performance and is related to health. Understanding the association between MIHS and MIHS relative (MIHSrel) and the absolute lean mass of the arm (LMarm) and the percentage of body fat (%BF) can provide important information for performance and health. The study aimed to investigate the correlation between MIHS and MIHSrel with the LMarm and the %BF of young judokas (sub-19, 15 males and 14 females). MIHS was measured using a multipurpose digital dynamometer with a load cell for computer. Body composition was measured by dual-energy X-ray absorptiometry (DXA). The correlation between MIHS, MIHSrel with LMarm and %BF was verified through Pearson's correlation, with a significance level of p < 0.05. Correlation between MIHSrel and %BF was very high only in female judokas for both arms (right, r = -0.76; left, r = -0.75). Correlations between LMarm and MIHS of the right and left arms ranged from very high to almost perfect for both sexes (r = 0.74 to 0.94). These results highlight the importance of strengthening the arms in young judokas, and controlling body fat for performance and health, especially in female judokas.

The relationship between handgrip strength and performance scores in North American Collegiate Division I women’s artistic gymnasts

Maximal isometric handgrip strength (HGS) is used as an indicator of overall muscular strength and has also been found to be predictive of certain athletic events sporting prowess. Women’s artistic gymnastics requires athletes have high levels of relative muscular strength and power to be successful. This study examined the relationship between HGS and gymnastics performance scores for the 4 events of vault, uneven bars, beam, and floor in female collegiate artistic gymnasts. Twenty-five (n=25) female National Collegiate Athletic Association (NCAA) Division I North American collegiate women’s artistic gymnasts (age: 20.1±1.3 yrs; height: 158.9±5.6 cm; mass: 58.2±5.3 kg) were assessed for a one-time measurement of absolute HGS in kg and relative HGS (HGS/height in m2), as well as their average vault, uneven bars, beam, and floor performance scores across a competitive season. Pearson correlation coefficients (r) were determined between HGS and all performance scores. No significant (p &amp;gt; 0.05) correlations were found between absolute HGS (30.8±4.4 kg) or relative HGS (12.0±1.6 kg/m2) and any 4 gymnastics event’s performance scores (r range: -0.07 – 0.50 or r range: -0.06 – 0.31, respectively). In this female collegiate gymnastics’ population, 56% had an absolute HGS and 80% had a relative HGS, respectively, above the 50th percentile of all similarly aged adult females in the United States. In the current population of female collegiate gymnasts, absolute and relative HGS were not related to any gymnastics events performance scores and adds to the existing literature, supporting no relationships between HGS and sports performances where sports movements require a high degree of technical precision and accuracy. Findings from this investigation can be used by athletes, coaches, and practitioners in the collegiate women’s gymnastics realm to assess if athletes have attained sufficient absolute HGS, and especially relative HGS values, to be successful.

Effects of immersive virtual reality on upper limb function in subjects with multiple sclerosis: A cross-over study

BackgroundUpper limb dysfunctions are common in people with multiple sclerosis (PwMS) and lead to limitations in activities of daily living. In this study, we investigated the feasibility and effects of an immersive commercial virtual reality system for upper limb bilateral rehabilitation. MethodsA total of 20 participants were included in a cross over study with two arm sequences: Treatment-Waiting List (T-WL; N = 9) and Waiting List-Treatment (WT-T; N = 11). T-WL sequence performed 12 sessions of bilateral UL rehabilitation over a 4-week period, based on the use of a commercially VR immersive platform (Oculus Rift), followed by a 4-week wash-out period and a 4-week waiting list period. WL-T sequence followed the protocol in the reverse order.Participants were tested at baseline (T0), after the end of the first 4-week period (T1), at the end of the wash-out period and finally at the end of the third 4-week period (T2). The primary outcome was the Box and Blocks test (BBT). Secondary outcome measures were: Nine Hole Peg Test (NHPT), Maximal isometric handgrip strength, Manual Ability Measure-36 (MAM-36), Modified Fatigue Impact Scale (MFIS), and the System Usability Scale (SUS).In absence of carryover effects, we analyzed primary and secondary outcome measures with mixed linear effect models. Treatment efficacy was assessed on the within-subject differences. Specifically, we used the intra-individual differences at the end of treatment and waiting-list periods (T1 and T2) as dependent variables and sequences (T-WL or WL-T) as independent variable. In presence of carryover effects (p-value <0.05), we assessed between sequence differences by an unpaired t-test considering T0 and T1 as time points, and sequence as group factor. ResultsWe observed clinical and statistical improvements for BBT, with an overall between-sequence difference of 8.6 ± 2.6 blocks (p < 0.01) favoring treatment period in the less affected side, and a not significant change of 3.0 ± 2.6 blocks (p = 0.28) in the most affected side. Small and not significant between-sequence differences were found for 9HPT, and handgrip strength in both sides. Similarly, no differences were found for patient reported outcomes, MFIS and MAM-36. Finally, mean SUS score was 45.9 ± 11.1 points, representing a moderate usability of the system. ConclusionAn immersive VR-based approach resulted useful to improve gross manual dexterity in the less affected limb in PwMS. However, such improvement did not translate into modifications in terms of self-reported ability to carry out activities of daily living nor went along with improvement in fine hand dexterity, strength or fatigue. Finally, usability of this technology was overall judged moderate, with lower scores assigned to items representing user-friendliness.

Reliability and Validity of Shoulder and Handgrip Strength Testing.

Purpose: This study aimed to estimate the intra- and inter-rater reliability of the JTECH computerized, wireless apparatus and its validity (compared to established devices) for measurements of maximal shoulder isometric strength and handgrip strength among healthy adults with no shoulder pathology. Methods: Twenty healthy young adults had shoulder strength tested with JTECH and Micro-FET2 hand-held dynamometers, and the handgrip strength was tested using JTECH and Jamar handgrip dynamometers. Assessments were performed by the same rater to determine intra-rater reliability and convergent validity, at least two days apart, while on a third visit, the other rater performed measures to determine inter-rater reliability. Results: The JTECH computerized, wireless devices demonstrated good to excellent intra-rater reliability (ICCs (2,1)=0.78-0.97) and inter-rater reliability for strength measures (ICCs (2,1)=0.76-0.95). The JTECH computerized device compared to the Micro-FET2 hand-held dynamometer showed substantial concurrent validity for shoulder flexion (R2=0.87), extension (R2=0.87), abduction (R2=0.88), and adduction (R2=0.85). Substantial concurrent validity was shown for the JTECH computerized device and Jamar handgrip dynamometers (R2=0.92). Conclusions: The JTECH computerized, wireless devices demonstrated high intra- and inter-rater reliability and substantial concurrent validity for shoulder isometric strength and handgrip strength in healthy adults.

Vitamin D supplementation and increased dairy protein intake do not affect muscle strength or physical function in healthy 6-8-year-old children: the D-pro randomized trial.

PurposeTo investigate separate and combined effects of vitamin D supplementation during the extended winter and increased dairy protein intake on muscle strength and physical function in children, and furthermore to explore potential sex differences.MethodsIn a 2 × 2-factorial, randomized winter trial, 183 healthy, 6–8-year-old children received blinded tablets with 20 µg/day vitamin D3 or placebo, and substituted 260 g/day dairy with yogurts with high (HP, 10 g protein/100 g) or normal protein content (NP, 3.5 g protein/100 g) for 24 weeks during winter at 55° N. We measured maximal isometric handgrip and leg press strength, and physical function by jump tests and a 30 s sit-to-stand test. Physical activity was measured by 7-day accelerometry.ResultsBaseline (mean ± SD) serum 25-hydroxyvitamin D was 80.8 ± 17.2 nmol/L, which increased to 88.7 ± 17.6 nmol/L with vitamin D supplementation and decreased to 48.4 ± 19.2 nmol/L with placebo. Baseline protein intake was 15.5 ± 2.4 E%, which increased to 18.4 ± 3.4 E% with HP and was unchanged with NP. We found no separate or combined effects of vitamin D supplementation and/or increased dairy protein intake on muscle strength or physical function (all P > 0.20). There was an interaction on the sit-to-stand test (Pvitamin×yogurt = 0.02), which however disappeared after adjusting for physical activity (P = 0.16). Further, vitamin D supplementation increased leg press strength relatively more in girls compared to boys (mean [95% CI] 158 [17, 299] N; Pvitamin×sex = 0.047).ConclusionOverall, vitamin D and dairy protein supplementation during the extended winter did not affect muscle strength or physical function in healthy children. Potential sex differences of vitamin D supplementation should be investigated further.Registered at clinicaltrials.govNCT0395673.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00394-022-02912-0.

Preliminary Research towards Acute Effects of Different Doses of Caffeine on Strength-Power Performance in Highly Trained Judo Athletes.

Although several previous studies examined the effect of pre-exercise caffeine ingestion on judo-specific performance, the optimal dose of caffeine to maximise the ergogenic effects for judoka is not clear. The main purpose of this study was to analyse the effects of oral administration of 3 and 6 mg/kg of caffeine on a battery of physical tests associated with judo performance. Ten highly trained national-level judoka (6 men and 4 women, age: 24.1 ± 4.7 years, body mass: 73.4 ± 12.9 kg, 15.1 ± 5.2 years of judo training experience, 2.6 mg/kg/day of habitual caffeine intake) participated in a randomized, crossover, placebo-controlled and double-blind experiment. Each judoka performed three identical experimental sessions after: (a) ingestion of 3 mg/kg of caffeine (CAF-3); (b) ingestion of 6 mg/kg of caffeine (CAF-6); (c) ingestion of a placebo (PLAC). After 60 min for substance absorption, participants performed the following tests: (a) bench press exercise with 50% of the load representing one-repetition maximum (1RM), including three sets of three repetitions; (b) bench pull exercise with 50% of 1RM including three sets of three repetitions; (c) countermovement jump; (d) maximal isometric handgrip strength test; (e) dynamic and isometric versions of the Judogi Grip Strength Test. In comparison with PLAC, the ingestion of CAF-3 and CAF-6 increased peak bar velocity in the bench press exercise (1.27 ± 0.11 vs. 1.34 ± 0.13 and 1.34 ± 0.15 m/s, respectively; p < 0.01) and mean bar velocity in the bench pull exercise (1.03 ± 0.15 vs. 1.13 ± 0.13 and 1.17 ± 0.15 m/s; p < 0.05). Only CAF-6 increased mean bar velocity in the bench press exercise when compared with PLAC (0.96 ± 0.09 vs. 1.02 ± 0.11 m/s; p < 0.05). Both CAF-3 and CAF-6 significantly increased the number of repetitions in the Judogi Grip Strength Test (17 ± 10 vs. 20 ± 10 and 20 ± 10 repetitions; p < 0.05). There were no differences between PLAC and caffeine doses in the remaining tests. The pre-exercise ingestion of 3 and 6 mg/kg of caffeine effectively obtained meaningful improvements in several aspects associated with judo performance. From a practical viewpoint, the selection between 3 or 6 mg/kg of caffeine may depend on previously tested individual responses during simulated competition.

Effect of Handgrip Training in Extreme Heat on the Development of Handgrip Maximal Isometric Strength among Young Males.

The aim of this study was to evaluate the acute and adaptive effects of passive extreme heat (100 ± 3 °C) exposition in combination with a strength training protocol on maximal isometric handgrip strength. Fifty-four untrained male university students participated in this investigation. Twenty-nine formed the control group (NG) and 25 the heat-exposed group (HG). All the participants performed a 3-week isotonic handgrip strength training program twice a week with a training volume of 10 series of 10 repetitions with 45-s rest between series, per session. All the subjects only trained their right hand, leaving their left hand untrained. HG performed the same training protocol in hot (100 ± 3 °C) conditions in a dry sauna. Maximal isometric handgrip strength was evaluated each training day before and after the session. NG participants did not experience any modifications in either hand by the end of the study while HG increased maximal strength values in both hands (p < 0.05), decreased the difference between hands (p < 0.05), and recorded higher values than the controls in the trained (p < 0.05) and untrained (p < 0.01) hands after the intervention period. These changes were not accompanied by any modification in body composition in either group. The performance of a unilateral isotonic handgrip strength program in hot conditions during the three weeks induced an increase in maximal isometric handgrip strength in both hands without modifications to bodyweight or absolute body composition.

Maximal isometric strength indices are associated with the oxygen cost of walking and running in recreationally active men and women

ABSTRACT This study assessed the associations of maximal isometric strength and movement economy in 126 recreationally active men and women. Oxygen consumption was assessed through a graded treadmill test with 4-minute increments (4–12 km∙h−1). Maximal isometric leg extensor, leg flexor and handgrip strength were assessed by isometric dynamometry. Models of best fit for gross oxygen cost and gross caloric unit cost were observed across the majority of velocities when the leg extensor/flexor strength ratio and handgrip strength were combined (R2 = 0.207–0.525 and R2 = 0.152–0.475, respectively). Additionally, the oxygen cost differed statistically for the majority of velocities when participants were split by the median of leg extensor strength (12.3–26.3 ml∙kg−1∙km−1, p < 0.05) and the average of all strength variables (13.9–30.3 ml∙kg−1∙km−1, p < 0.05). Our data underline the importance of maintaining maximal strength in order to perform activities with low to moderate oxygen demands.

Caffeine ingestion increases the upper-body intermittent dynamic strength endurance performance of combat sports athletes

ABSTRACT The aim of this study was to investigate the effects of caffeine ingestion on upper-body intermittent strength endurance performance of combat sports athletes. Using a double-blind and placebo-controlled crossover design, ten experienced judo and jiu-jitsu athletes performed an upper-body intermittent strength endurance protocol (four set of judogi dynamic strength endurance test, interspersed by 3-min recovery intervals) 60 min after ingesting either caffeine (5 mg·kg−1) or placebo. Compared with placebo condition, caffeine ingestion significantly increased the total number of repetitions (+ 7%, P = 0.04; d = 0.44) and the maximal isometric handgrip strength (+ 5%, P = 0.03, = 0.41). Rating of perceived exertion, heart rate and blood lactate concentration increased linearly throughout the test (P < 0.05), but without significant differences between caffeine and placebo conditions (P > 0.05). Caffeine ingestion improved the upper-body intermittent strength endurance performance and maximal isometric strength of combat sports athletes. This suggests that caffeine could help to maintain high levels of maximal handgrip and endurance strength in upper limbs, especially forearm muscles, which are responsible for maintaining the grip on the opponent’s judogi. Highlights Caffeine ingestion improved upper-body intermittent strength endurance of grappling athletes. Caffeine ingestion increased maximal isometric handgrip strength of grappling athletes. Heart rate, lactate concentration or rating of perceived exertion were not affected by caffeine ingestion. Our findings suggest that caffeine could help to maintain high levels of maximal handgrip and endurance strength in upper limbs, especially forearm muscles, which are responsible for maintaining the grip on the opponent's judogi.

Evaluation of Maximal Isometric Hand Grip Strength in Different Sports

Background: Grip strength has proven to have a positive effect on sports performance in which a sportimplement is grasped in the hand.Objective: To compare Hand Grip Strength in males of different sports.Materials and Methods: 400 male sportsmen, 100 in each sport (Cricket, Hockey, Tennis and Badminton)aged 18-25 yrs volunteered to participate in this study were engaged. Each participant was asked to performat least three maximal isometric grip strength measurements using a Jamar Handgrip Dynamometer and theaverage of the three grip strength trials readings was recorded.Statistical analysis: R-Programming Language Software was applied for statistical analyses of the data; theresults were statistically analyzed by ANOVA.Results: The findings of the present study showed that the maximum grip strength measured in both handsis higher in Cricket players than in Hockey, Tennis and Badminton players (P&lt;0.05).Conclusion: In the present study hand grip strength might have increased due to regular training. It wouldbe beneficial to the sportsmen in terms of optimizing training programs separately for particular sports.

Strength training and gross-motor skill exercise as interventions to improve postural control, dynamic functional balance and strength in older individuals.

Loss of balance control is commonly experienced by older individuals. Despite the large amount of research on the effects of exercise on balance the optimal exercise regime is yet to be identified. Most studies have concentrated on strength training due to associations between muscle weakness, balance disfunction and fall risk. The effects of gross-motor skill exercise for balance and postural control have been less investigated. The study aimed to compare the effectiveness of strength training (STT) and gross-motor skill exercise (GMT) on static postural control, dynamic functional balance and strength in healthy older individuals. Thirty-eight individuals (65-85 years) participated to GMT or STT for 12 weeks, twice weekly. They were tested pre- and post-training for postural control (Romberg and Tandem positions on a force platform), dynamic functional balance (maximal walking speed in balance-challenging conditions), maximal isometric handgrip strength, maximal knee flexor and extensor strength. Improvements were observed in static postural balance (tandem position, P<0.05, -1.07 mm/s), walking speed (hurdles P<0.01, +0.08 m/s; narrow path P<0.05, +0.07 m/s; picking up P<0.01, +0.07 m/s) knee extensor strength (P<0.001, +10.9 Nm); knee flexor strength improved significantly in the SST group only (P<0.001, +13.9 Nm). There was no correlation between changes in strength and balance. Static postural balance and dynamic functional balance in healthy elderly may be improved through exercise targeting either muscular strength or coordination, agility and mobility. The present study helps fill the gap in research on gross-motor skill exercise and proposes a suitable exercise alternative to strength for managing static and dynamic balance decline.