Muscle Strength In Healthy Adults Research Articles

Comparative analysis of body composition using torso CT from PET/CT with bioelectrical impedance and muscle strength in healthy adults

The role of torso computed tomography (CT) in evaluating body composition has been unexplored. This study assessed the potential of low-dose torso CT from positron emission tomography (PET)/CT for analyzing body composition and its relation to muscle strength. We retrospectively recruited 384 healthy Korean adults (231 men, 153 women) who underwent torso 18F-FDG PET/CT, bioelectrical impedance analysis (BIA), and muscle strength tests (handgrip strength [HGS] and knee extension strength [KES]). CT images were segmented into three compartments: torso volumetric, abdominal volumetric, and abdominal areal. Muscle amounts from each compartment were indexed to height (m2). BIA and HGS served as reference standards, with correlation coefficients (r) calculated. Torso muscle volumetric index (TorsoMVI) had the strongest correlations with BIA-derived values (r = 0.80 for men; r = 0.73 for women), surpassing those from the abdominal compartments. TorsoMVI was also correlated significantly with HGS (r = 0.39, p < 0.01) and differentiated between normal and possible sarcopenia in men (n = 225, 5960 ± 785 cm3/m2 vs. n = 6, 5210 ± 487 cm3/m2, p = 0.02). In women, KES correlated more strongly with muscle parameters than HGS. Despite gender-specific variations, torso CT-derived parameters show promise for evaluating body composition and sarcopenia.

Quantitative multi-parameter assessment of age- and gender-related variation of back extensor muscles in healthy adults using Dixon MR imaging.

Investigate sex differences in age-related back extensor muscle degeneration using Dixon MRI and analyze the relationship between quantitative muscle parameters and back muscle strength in healthy adults. 105 healthy subjects underwent lumbar Dixon MRI. Fat fraction (FF), cross-sectional area (CSA), functional CSA (FCSA), and relative FCSA (RFCSA) of multifidus muscle (MF) and erector spinae (ES) were quantified. Back extension muscle strength was measured using an external fixation dynamometer. ANOVA with post hoc Tukey correction was used for age group comparisons. Partial and Spearman's correlation analyzed relationships between age, muscle parameters, and muscle strength. MF and ES FF significantly increased with age in both genders (r = 0.55-0.85; p < 0.001). Muscle FF increased prominently for females (40-49years, MF and 50-59years, ES) and males (60-73years, MF and ES). In females, total ES FCSA and RFCSA (r = - 0.42, - 0.37; p < 0.01) correlated with age. While in males, all MF and ES muscle size parameters, except total MF CSA, correlated with age (r = - 0.30 to - 0.58; p < 0.05). Back extension muscle strength correlated with mean FF, total CSA, and total FCAS for MF and ES individually (p < 0.001). The combined MF + ES FCSA correlation coefficient (r = 0.63) was higher than FF (r = - 0.51) and CSA (r = 0.59) (p < 0.001). Age-related back extensor muscle degeneration varies by muscle type and sex. FCSA has the highest association with back muscle strength compared to FF and CSA. The investigation of sex differences in age-related back extensor muscle degeneration utilizing Dixon imaging may hold significant implications for evaluating spine health and enabling earlier intervention. Muscles' FCSA could contribute to acquiring additional evidence for reflecting muscle function change. • The multifidus muscle (MF) and erector spinae (ES) fat fraction (FF) increased with age at all lumbar disc levels in females and males. • Age-related changes in muscle morphological quantitative parameters of healthy adults were specific by muscle type and gender. • The muscle functional cross-sectional area (FCSA) measured by Dixon imaging may better monitor back extensor muscle strength changes than muscle FF and cross-sectional area (CSA).

Foam Rolling Acute Effects on Myofascial Tissue Stiffness and Muscle Strength: A Systematic Review and Meta-Analysis.

Glänzel, MH, Rodrigues, DR, Petter, GN, Pozzobon, D, Vaz, MA, and Geremia, JM. Foam rolling acute effects on myofascial tissue stiffness and muscle strength: a systematic review and meta-analysis. J Strength Cond Res 37(4): 951-968, 2023-Foam rolling (FR) is widely used in rehabilitation and physical training. However, the effects of FR on myofascial tissue stiffness and muscle strength remain unclear. This study aimed to perform a systematic review with meta-analysis of trials that tested the FR acute effects during warm-up on the myofascial tissue stiffness and muscle strength in healthy adults or athletes. This systematic review (CRD42021227048) was performed according to Cochrane's recommendations, with searches performed in PubMed, Web of Science, Embase, and PEDro databases. Syntheses of included studies' data were performed, and the PEDro scale was used to assess the methodological quality of the studies. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluations approach. Twenty included studies assessed trunk and thigh fascial tissue stiffness, and thigh and calf muscle stiffness, whereas muscle strength was assessed in the knee extensors and flexors, and plantar flexors muscles. Qualitative analysis showed decreases in fascial ( n = 2) and muscle ( n = 5) stiffness after FR. However, the meta-analysis showed no effects of FR on myofascial tissue stiffness. Both qualitative and quantitative analyses showed no effects of FR on isometric muscle strength, eccentric torque, and rate of force development. However, the knee extensor concentric torque increased after FR. Foam rolling increases the knee extensor concentric torque, but it does not acutely change the myofascial tissue stiffness and isometric muscle strength. However, evidence of these studies provides low certainty to state that FR does not change these parameters. Therefore, high methodological quality studies should be performed to better ascertain the effects of FR on the myofascial tissue stiffness and muscle strength.

Increasing Protein Ingestion Minimally Increases Lean Mass and Muscle Strength in Subjects Enrolled in Resistance Exercise Training a Systematic Review and Meta-Analysis

ObjectivesThis systematic review, meta-analysis, and meta-regression aimed to determine if increasing daily protein ingestion contributes to gaining lean mass (LM), muscle strength, and physical/functional test performance in healthy persons.MethodsThe present review was registered on PROSPERO - CRD42020159001. A systematic search in Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Randomized controlled trials (RCT) including healthy and non-obese adult participants increasing daily protein intake were selected. Subgroup analysis, splitting the studies by participation in resistance exercise training (RE), age (< 65 or ≥ 65 y), and daily protein ingestion were also performed.Results74 RCT fit our inclusion criteria. The age range of the participants was 19 to 85 y, and study protocols in the trials lasted from 6 to 108 wks (76% of the studies between 8 and 12 wks). In ∼80% of the studies, baseline protein ingestion was at least 1.2 g of protein/kg/d. Increasing daily protein ingestion may lead to small gains in LM in subjects enrolled in RE (SMD [standardized mean difference] = 0.22, CI95% [95% confidence interval] 0.14:0.30, P < 0.01, 62 studies, moderate level of evidence). Also, ≥ 65 y subjects ingesting 1.2–1.59 g of protein/kg/d and younger subjects (< 65 y) increasing their ingestion to ≥ 1.6 g of protein/kg/d during RE showed a higher LM gain. Lower-body strength gain was slightly higher at ≥ 1.6 g of protein/kg/d during RE (SMD = 0.40, CI95% 0.09:0.35, P < 0.01, 19 studies, low level of evidence). Bench press strength was slightly increased by ingesting more protein in < 65 y subjects during RE (SMD = 0.18, CI95% 0.03:0.33, P = 0.01, 32 studies, low level of evidence). Effects on handgrip strength are unclear and only marginal for performance in physical function tests.ConclusionsThe number of studies increasing daily protein ingestion alone was too low (n = 6) to conduct a meta-analysis. The current evidence shows that increasing protein ingestion by consuming supplements or food, resulted in small additional gain in LM, and lower body muscle strength in healthy adults enrolled in RE. Effects on bench press strength and performance in physical function tests are minimal. The effect on handgrip strength was unclear.Funding SourcesThis research received a grant from the International Life Science Institute (Europe) and CNPq.

The performance of balance exercises during daily tooth brushing is not sufficient to improve balance and muscle strength in healthy older adults

BackgroundHigh prevalence rates have been reported for physical inactivity, mobility limitations, and falls in older adults. Home-based exercise might be an adequate means to increase physical activity by improving health- (i.e., muscle strength) and skill-related components of physical fitness (i.e., balance), particularly in times of restricted physical activity due to pandemics.ObjectiveThe objective of this study was to examine the effects of home-based balance exercises conducted during daily tooth brushing on measures of balance and muscle strength in healthy older adults.MethodsFifty-one older adults were randomly assigned to a balance exercise group (n = 27; age: 65.1 ± 1.1 years) or a passive control group (n = 24; age: 66.2 ± 3.3 years). The intervention group conducted balance exercises over a period of eight weeks twice daily for three minutes each during their daily tooth brushing routine. Pre- and post-intervention, tests were included for the assessment of static steady-state balance (i.e., Romberg test), dynamic steady-state balance (i.e., 10-m single and dual-task walk test using a cognitive and motor interference task), proactive balance (i.e., Timed-Up-and-Go Test [TUG], Functional-Reach-Test [FRT]), and muscle strength (i.e., Chair-Rise-Test [CRT]).ResultsIrrespective of group, the statistical analysis revealed significant main effects for time (pre vs. post) for dual-task gait speed (p < .001, 1.12 ≤ d ≤ 2.65), TUG (p < .001, d = 1.17), FRT (p = .002, d = 0.92), and CRT (p = .002, d = 0.94) but not for single-task gait speed and for the Romberg-Test. No significant group × time interactions were found for any of the investigated variables.ConclusionsThe applied lifestyle balance training program conducted twice daily during tooth brushing routines appears not to be sufficient in terms of exercise dosage and difficulty level to enhance balance and muscle strength in healthy adults aged 60–72 years. Consequently, structured balance training programs using higher exercise dosages and/or more difficult balance tasks are recommended for older adults to improve balance and muscle strength.

Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis.

This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 repetitions maximum (RM)), moderate- (9-15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses. Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113-0.469) or subgroup analysis (P = 0.871-0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031-0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60-0.63 and 0.34-0.35, respectively; P < 0.001-0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26-0.28, P = 0.068). Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.

RELIABILITY OF MAKE AND BREAK TESTS IN ASSESSING INTRINSIC FOOT MUSCLE STRENGTH USING A HANDHELD DYNAMOMETER IN HEALTHY YOUNG ADULTS

Purpose: The make and break tests are used in isometric muscle measurement via a handheld dynamometer. This study aimed to compare the reliability of intrinsic foot muscle strength assessment with break and make tests in healthy young adults. Methods: Seventy-five healthy adults completed the test-retest protocol with five days between tests. The maximal isometric strength measure of intrinsic foot muscles was measured during make/break tests using a handheld dynamometer. Test-retest reliability was calculated using intra-class correlation coefficients (ICC). Minimal detectable changes were calculated using standard error measurements. Results: According to the analysis, the strength results of the break test were higher in all muscles when compared to the make test (p&amp;lt;0.05). The strength measurements of the intrinsic foot muscles was found to have almost perfect test-retest reliability in the make and break test (ICC=0.938-0.986). Conclusion: Healthy adults showed stable test-retest results on all muscle strength measurements of the intrinsic foot muscles. The make and break test carried out usnig the handheld dynamometer is a reliable method for assessing intrinsic foot muscle strength in healthy adults. Both make and break tests are reliable measurements for the strength of intrinsic foot muscles.

Prediction equation of hip external rotators maximum torque in healthy adults and older adults using the measure of hip extensors maximum torque

BackgroundThe use of predictive equation of muscular torque can reduce physical effort and time spent during evaluation. ObjectivesTo establish, validate, and test the accuracy of a prediction equation to estimate the hip external rotators (HER) torque in adults and older adults by means of hip extensors (HEX) torque measurement. MethodsEighty-three healthy adults (development set) were assessed to test the association of HEX and HER torques and to establish the prediction equation. A separate 36 adults and 15 older adults (validation sets) were assessed to test the ability of the equation to estimate HER torque. Hip isometric strength was assessed by a handheld dynamometer. ResultsSimple linear regression analysis revealed that HEX torque was associated with HER torque (r=0.80; p<0.0001), resulting in the following prediction equation: HERtorque=−0.02+(0.58 * HEXtorque). Paired t-test revealed no difference between directly measured and predicted values of HER torque in adults (mean difference=0.02; 95% CI=−0.115, 0.072) and older adults (mean difference=0.05; 95% CI=−0.02, 0.12). ConclusionThe HEX and HER torques were strongly correlated. The prediction equation was valid, accurate, and can be used to estimate HER muscle strength in healthy adults and older adults, requiring only the direct measurement of HEX torque.

Relationships between Foot Morphology and Foot Muscle Strength in Healthy Adults.

The purpose of this study was to investigate if measurements of foot morphology in sitting and standing positions can predict foot muscle strength. Twenty-six healthy male adults were recruited, and their foot morphology and foot muscle strength were measured. Foot morphological variables, toe flexor strength, and metatarsophalangeal joint flexor strength were measured by using a digital caliper, Ailitech-AFG500 dynameter and metatarsophalangeal joint flexor strength tester, respectively. Partial correlation and multivariate stepwise regression were used to explore the relationships between foot morphology and toe/metatarsophalangeal joint strength. Results adjusted by age and body mass index were as follows: (1) truncated foot length in sitting and standing positions and foot width in standing position were positively correlated with the flexor strength of the first toe; (2) foot length, foot width, and truncated foot length in both positions were positively related to the flexor strength of the other toes; (3) arch height index in sitting position and differences in navicular height were negatively associated with the flexor strength of the other toes; (4) differences in foot width were negatively associated with metatarsophalangeal joint flexor strength; and (5) the multivariate stepwise regression model showed that truncated foot length in sitting position, navicular height in standing position, differences in navicular height, foot width in sitting position, and differences in foot width were significantly correlated with toe/metatarsophalangeal joint flexor strength. Simple measurements of foot morphological characteristics can effectively predict foot muscle strength. Preliminary findings provided practical implications for the improvement of the foot ability by making specific foot muscle training sessions in professional sports and by compensating the predicted muscle strength defects to prevent foot injury.

Effects of plyometric training on jumping, sprint performance, and lower body muscle strength in healthy adults: A systematic review and meta-analyses.

To determine the effect of lower body plyometric training (PLY) on jumping, sprint performance, and lower body muscle strength in healthy adults. A systematic literature search (PubMed, Embase) was performed. Studies were included if they (a) described a lower body PLY intervention lasting ≥4weeks; (b) included measures of jumping, sprint, and/or lower body muscle strength; (c) included healthy individuals ≥18years; (d) included a training or non-training control group; and (e) were written in English. Meta-analyses identifying the effects of PLY on jumping, sprint, and lower body muscle strength were conducted providing the standardized mean difference (SMD). A total of 826 records were identified of which 25 fulfilled the inclusion criteria, yielding 19, 11, and seven data points for the meta-analyses of jumping, sprint performance, and lower body muscle strength, respectively. The data showed improvements for all three performance variables after 4-12weeks of PLY. The SMD (CI95%) across studies for jump height, sprint time, and muscle strength were 0.45 (0.16: 0.75), -0.59 (-1.01: -0.17), and 0.33 (0.03: 0.63), respectively, where the latter two showed within-sample heterogeneity. The systematic review and meta-analyses showed that PLY elicits a small-to-moderate positive effect on jumping, sprint performance, and lower body muscle strength in healthy adults being recreationally active or athletes.

Leg Dominance Effect on Isokinetic Muscle Strength of Hip Joint

ObjectiveThe purpose of this study was to compare the isokinetic strength of hip muscles in dominant vs nondominant legs in healthy adults. MethodsThirty-two healthy college students (15 male and 17 female) volunteered to participate in this study. A Biodex system 3 was used to measure isokinetic peak torque at an angular velocity of 60°/s for the hip flexors, extensors, abductors, and adductors in both dominant and nondominant legs. Hip flexors and extensors were tested from the supine lying position while hip abductors and adductors were tested from the side lying position using concentric mode of muscle contraction. ResultsThere were no statistically significant differences between the dominant and nondominant sides for all tested hip muscles. ConclusionLeg dominance does not appear to affect hip muscle strength in healthy adults. This may be used as normative data for those with differences in muscle strength between involved and uninvolved sides.

Upper-Body Exercises With External Resistance Are Well Tolerated and Enhance Muscle Activity in People With Hemophilia.

Conventional nonresisted therapeutic exercises for people with hemophilia involve a careful, low-intensity approach to avoid injuries. Externally resisted exercise is highly efficient for increasing muscle strength in healthy adults but its feasibility for people with hemophilia remains unknown. The purpose of this study was to evaluate muscle activity during upper-body rehabilitation exercises with 2 types of external resistance and without external resistance (conventional) and to examine tolerability, kinesiophobia, and possible adverse effects derived from the session. This was a cross-sectional study. Twelve people with hemophilia A/B (11 with severe hemophilia undergoing prophylactic treatment, 1 with mild hemophilia) participated. During the experimental session, participants completed the Tampa Scale of Kinesiophobia and performed 2 exercises-elbow flexion and shoulder abduction-with 3 conditions for each exercise: elastic resistance (externally resisted), free weights (externally resisted), and conventional nonresisted. Surface electromyography signals were recorded for the biceps brachii, triceps brachii, upper trapezius, and middle deltoid muscles. After the session, exercise tolerability and kinesiophobia were assessed. Adverse effects were evaluated 24 and 48 hours after the session. Externally resisted exercises provided greater muscle activity than conventional nonresisted therapeutic exercises. The exercises were generally well tolerated and there was no change in kinesiophobia following the session. No adverse effects were observed in the following days. Small sample size was the main limitation. In people with severe hemophilia undergoing prophylactic treatment, elbow flexion and shoulder abduction exercises with external resistance at moderate intensities are feasible and provide greater muscle activity than nonresisted conventional exercises.

Relationship of Circulating Growth and Differentiation Factors 8 and 11 and Their Antagonists as Measured Using Liquid Chromatography-Tandem Mass Spectrometry With Age and Skeletal Muscle Strength in Healthy Adults.

Growth and differentiation factors 8 (GDF8) and 11 (GDF11) have attracted attention as targets for rejuvenating interventions. The biological activity of these proteins may be affected by circulating antagonists such as their respective prodomains, follistatin (FST315), WFIKKN1, and WFIKKN2. Reports of the relationship of GDF8 and GDF11 and their antagonists with aging and aging phenotypes such as skeletal muscle strength have been conflicting possibly because of difficulties in measuring these proteins and polypeptides. Plasma GDF8 and GDF11 and their antagonists were measured using a multiplexed selected reaction monitoring assay and liquid chromatography-tandem mass spectrometry in 160 healthy adults aged 22-93 years. Quadriceps strength was measured by knee extensor torque using isokinetic dynamometry. Spearman correlations with age were the following: GDF11 prodomain (r = .30, p = .001), GDF11 mature protein (r = .23, p = .004), FST315 (r = .32, p < .0001), WFIKKN1 (r = -.21, p = 0.008), and WFIKKN2 (r = .18, p = .02). Independent of age, FST315 and WFIKKN1 were negatively associated with knee strength (p = .02, p = .03, respectively) in a multivariable model that included both GDF8 and GDF11 mature proteins. When measured by an antibody-free selected reaction monitoring assay, GDF8, GDF11, and their antagonists are found in the circulation in the ng/mL range. In healthy adults, plasma GDF11 and antagonists FST315, WFIKKN1, and WFIKKN2 differed by age. Antagonists of GDF8 and GDF11, but not GDF8 and GDF11, were independently associated with skeletal muscle strength. Further work is needed to characterize the relationship of these protein and polypeptides with sarcopenia-related phenotypes such as physical function and walking disability.

The influence of kinesiology tape colour on performance and corticomotor activity in healthy adults: a randomised crossover controlled trial

BackgroundThere exists conflicting evidence regarding the impact of kinesiology tape on performance and muscle function. One variable that may account for disparities in the findings of previous studies is the colour of the tape applied. Colour is hypothesised to influence sporting performance through modulation of arousal and aggression. However, few studies have investigated the influence of colour on products designed specifically to enhance athletic performance. Further, no studies have investigated the potential influence of colour on other drivers of performance, such as corticomotor activity and neuromuscular function. Thus, the aim of this study was to investigate the influence of kinesiology tape colour on athletic performance, knee extensor torque, and quadriceps neuromuscular function.MethodsThirty two healthy participants were assessed under five conditions, applied in random order: (1) no kinesiology tape (control), (2) beige-coloured kinesiology tape applied with tension (sham A), (3) beige-coloured kinesiology tape applied with no tension (sham B), (4) red-coloured kinesiology tape applied with tension, and (5) blue-coloured kinesiology tape applied with tension. Athletic performance was assessed using a previously validated hop test, knee extensor torque was measured using an isokinetic dynamometer, and transcranial magnetic stimulation was utilised to provide insight into the neuromuscular functioning of the quadriceps musculature.ResultsKinesiology tape had no beneficial impact on lower limb performance or muscle strength in healthy adults. The colour of the tape did not influence athletic performance (F (4, 120) = 0.593, p = 0.669), quadriceps strength (F (4, 120) = 0.787, p = 0.536), or neuromuscular function (rectus femoris: F (2.661, 79.827) = 1.237, p = 0.301).ConclusionThis study found that kinesiology tape does not alter lower limb performance or muscle function in healthy adults, irrespective of the colour of the tape applied. Future research should seek to confirm these findings beyond the research setting, across a range of sports, and at a range of skill levels.Trial registrationAustralian New Zealand Clinical Trials Registry. ACTRN12616001506482. Prospectively registered on 01/11/2016.

The influence of resting blood pressure on muscle strength in healthy adults.

Adverse alterations in the skeletal muscle response to exercise have been noted among adults with hypertension. The influence of resting blood pressure (BP) on muscle strength is unknown. We hypothesized that adults with high BP would exhibit lower muscular strength than adults with normal BP. An isokinetic dynamometer tested 21 measures of isometric and isokinetic muscle strength. BP was measured by auscultation. Patients were categorized into having normal (<120 and <80 mmHg) or high (≥120 and/or ≥80 mmHg) BP. Height (cm) and weight (kg) were measured to calculate BMI (kg/m). Analysis of covariance tested differences in muscle strength between BP groups with sex, age, and height as covariates. Patients [420 (49%) men] were middle-aged (44.1±16.1 years) and overweight (26.4±4.8 kg/m) with 187 having normal (107.7±7.3/68.3±6.3 mmHg) and 233 having high (127.8±9.8/80.8±8.1 mmHg) BP. For upper body, three of five extension measures and five of five flexion measures, as well as handgrip, were greater in the high than the normal BP group (P≤0.05). For lower body, five of five extension measures were greater in the high than the normal BP group, whereas there were no differences between BP groups for the five flexion measures (P>0.05). Contrary to our hypothesis, adults with high BP displayed greater muscle strength than adults with normal BP. Reasons for our findings are unclear, but may be because of shifts in muscle fiber type from type I to type IIb/x and oxidative to glycolytic metabolism; alterations may result in a more strength-adapted phenotype among adults with high BP such as we observed.

Reference Range of Respiratory Muscle Strength and Its Clinical Application in Amyotrophic Lateral Sclerosis: A Single-Center Study.

Background and PurposeEvaluating respiratory function is important in neuromuscular diseases. This study explored the reference ranges of the maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) in healthy adults, and applied them to amyotrophic lateral sclerosis (ALS) patients.MethodsMIP, MEP, and SNIP were measured in 67 healthy volunteers aged from 21 to 82 years. Reference ranges were evaluated by multivariate regression analysis using the generalized additive modeling of location, scale, and shape method. Thirty-six ALS patients were reviewed retrospectively, and abnormal values of MIP, MEP, and SNIP were determined according to the reference ranges.ResultsMIP, MEP, and SNIP were abnormal in 57.1%, 51.4%, and 25.7% of the ALS patients, respectively. MIP and SNIP were significantly correlated with the degree of restrictive pattern and respiratory symptoms. The ALS Functional Rating Scale-Revised score was correlated with SNIP.ConclusionsThis study has provided the reference range of respiratory muscle strength in healthy adults. This range is suitable for evaluating respiratory function in ALS patients.

Dietary milk fat globule membrane supplementation combined with regular exercise improves skeletal muscle strength in healthy adults: a randomized double-blind, placebo-controlled, crossover trial.

BackgroundOur previous studies demonstrated that dietary supplementation with milk fat globule membrane (MFGM) combined with habitual exercise improved muscle strength by stimulating neuromuscular development in mice. This study aimed to demonstrate the beneficial effects of dietary MFGM supplementation plus regular exercise on muscle strength and neuromuscular function in healthy humans.MethodsThe study was designed as a randomized, double-blind, placebo-controlled, crossover trial. Fourteen Japanese adults aged 31–48 years took daily MFGM (1 g) or placebo tablets during the 4-week study period and attended a training program twice a week. Physical function tests and surface electromyography (EMG) were conducted at baseline and at the end of the study period.ResultsThe MFGM group had significantly greater leg extension strength than the placebo group after the 4-week study period. Surface EMG showed that the MFGM group had a significantly higher root mean square amplitude than the placebo group, which indicated that the MFGM group had higher motor unit activity.ConclusionsDietary MFGM supplementation combined with regular exercise improves skeletal muscle strength, which may be due to increased motor unit recruitment in healthy Japanese middle-aged adults.

The Longitudinal Relation between Smoking and Muscle Strength in Healthy Adults

Aim: To assess longitudinally whether smoking tobacco is related to muscle strength in healthy adults and to assess the influence of lifestyle covariates on this relation. Methods: Data were obtained from the observational Amsterdam Growth and Health Longitudinal Study, with four repeated measurements at the ages of 21 (n = 181), 27 (n = 144), 32 (n = 426) and 36 (n = 373) years. Knee muscle strength (KMS) was measured at an angle of 300° per second. Smoking and the covariates physical activity and dietary intake were assessed with a questionnaire. Other covariates included physical fitness and body fat percentage. Cardiopulmonary fitness was assessed with a maximal running test and body fatness with skinfold measurements. Sex-specific longitudinal analyses were carried out using generalized estimating equations. Results: In men and women, an inverse relationship between smoking tobacco and KMS was found. Smoking 100 g of tobacco a week resulted in a reduction of 2.9% in KMS in men and a reduction of 5.0% in women. This relation existed largely independently of lifestyle covariates. Conclusion: This study indicates that smoking is inversely related to skeletal muscle strength in healthy adults.