Forearm Muscle Mass Research Articles

The impact of fine motor activities like playing musical instruments on the thickness and strength of the flexor digitorum muscle

BackgroundThis study aimed to explore the impact of occupational activities involving extensive finger movement on the muscular characteristics of the forearms. In particular, the flexor digitorum (FD) muscular thickness and strength asymmetry between right and left hand were compared between musicians and non-musicians.MethodsUltrasonography was employed to measure the thickness of the FD in each hand, while a validated custom-made device was used to assess the strength of the flexor and extensor digitorum (ED). Initially, muscle differences were estimated by computing the asymmetry index between dominant and non-dominant hands. To assess potential occupational disparities, comparisons of the asymmetry index were conducted between 25 right-handed instrumental musicians and 25 right-handed non-musicians.ResultsMusicians exhibited lower asymmetry between dominant and non-dominant hands in both FD thickness and ED strength when compared to non-musicians. This effect was particularly pronounced in musicians playing instruments that extensively use the left-hand fingers (e.g., violinists).ConclusionsOccupational activities, such as playing a musical instrument, can alter forearm muscle mass and strength distribution between dominant and non-dominant hands. This underscores the importance of considering occupational parameters in clinical or experimental interventions and musculoskeletal assessments.

Myological variation in the forearm anatomy of Callitrichidae and Lemuridae.

The anatomy of the primate forearm is frequently investigated in terms of locomotor mode, substrate use, and manual dexterity. Such studies typically rely upon broad, interspecific samples for which one or two representative taxa are used to characterize the anatomy of their genus or family. To interpret variation between distantly related taxa, however, it is necessary to contextualize these differences by quantifying variation at lower hierarchical levels, that is, more fine-grained representation within specific genera or families. In this study, we present a focused evaluation of the variation in muscle organization, integration, and architecture within two speciose primate families: the Callitrichidae and Lemuridae. We demonstrate that, within each lineage, several muscle functional groups exhibit substantial variation in muscle organization. Most notably, the digital extensors appear highly variable (particularly among callitrichids), with many unique configurations represented. In terms of architectural variables, both families are more conservative, with the exception of the genus Callimico-for which an increase is observed in forearm muscle mass and strength. We suggest this reflects the increased use of vertical climbing and trunk-to-trunk leaping within this genus relative to the more typically fine-branch substrate use of the other callitrichids. Overall, these data emphasize the underappreciated variation in forearm myology and suggest that overly generalized typification of a taxon's anatomy may conceal significant intraspecific and intrageneric variation therein. Thus, considerations of adaptation within the forearm musculature should endeavor to consider the full range of anatomical variation when making comparisons between multiple taxa within an evolutionary context.

Handgrip strength as determinant of upper body strength/physical fitness: a comparative study among individuals performing gymnastics (ring athletes) and gymnasium (powerlifters)

Background: This study was conducted on two different exercising groups, that is, gymnasium (powerlifters) and gymnastics (ring users). Although the type of physical activity is different, but both of the groups require stamina and coordination of central nervous system and skeletal muscles. In the two groups, the muscle strength of the upper body is remarkable and the handgrip has to be effectual for holding rings (gymnastics) and weights (gymnasium). Also, the time for which the grip can be maintained, which determines the endurance of the individual, is vital. Objective: To find the difference in handgrip strength (HGS) and handgrip endurance (HGE) among the two physically active groups. Materials and Methods: This study was conducted on a total of 75 subjects, divided into three groups of 25 each, namely, gymnastics, gymnasium, and control, that is, non-exercising group. Anthropometric hand measurements and skinfold thickness, forearm circumference, and forearm muscle were taken with HGS and HGE. Statistical analysis was then done to draw inference. Result: The study revealed statistically significantly high HGS and HGE in exercising group, in comparison to the control group, also the HGS was maximum in the gymnasium group (p < 0.0001). Moreover, the forearm circumference and the forearm muscle area were maximum (p < 0.0001) and the skin fold thickness was found to be the least in the gymnasium group. The study revealed positive correlation among HGS and HGE with forearm muscle mass. Thus, the study concluded the positive effect of physical activities on HGS and the weight training of the muscles increases their efficiency due to more acquisition of strength and development. Conclusion: In view of the fact that our day-to-day activities, right from household work, official work, to sports, require good HGS, a consistent assessment of handgrip forms an integral part of rehabilitation, not only to assess the strength of muscles involved in gripping but also to apply as a tool in rehabilitating patients with variable levels of hand injuries and in many clinical conditions such as diabetes. Also, in the field of sports, it affects the performance and, therefore, can be implemented as a useful parameter by the coach in their fitness and training program.

Abnormal bone geometry at the metacarpal bone shaft of rheumatoid arthritis patients with maintained muscle–bone relationship

Metacarpal juxtaarticular bone is altered in rheumatoid arthritis (RA). However, a detailed analysis of disease-related geometric adaptations of the metacarpal shaft is missing. The aim of the present study was to assess the role of RA disease, forearm muscle cross-sectional area (CSA), age, and sex on bone geometry at the metacarpal shaft. In 64 RA patients and 128 control subjects, geometric properties of the third metacarpal bone midshaft and forearm muscle CSA were measured by peripheral quantitative computed tomography (QCT). Linear models were performed for cortical CSA, total bone CSA, polar stress-strain index (SSI; a surrogate for a bone's resistance to bending and torsion), cortical thickness, and the metacarpal index (MI; cortical CSA/total CSA), with the explanatory variables muscle CSA, age, RA status, and sex. Forearm muscle CSA was associated with cortical and total metacarpal CSA and polar SSI. RA group status was associated with all bone parameters except cortical CSA. There was a significant interaction between RA status and age, indicating that the RA group had a greater age-related decrease in cortical CSA, cortical thickness, and the MI. Bone geometry of the metacarpal shaft is altered in RA patients compared to healthy controls. Whereas bone mass of the metacarpal shaft is adapted to forearm muscle mass, cortical thickness and the MI are reduced, but outer bone shaft circumference and the polar SSI increased in RA patients. These adaptations correspond to an enhanced aging pattern in RA patients.

Cancer Fatigue: Does Forearm Muscle Mass and Handgrip Correlate with Fatigue Severity? (714)

1.Discuss the concept of “catastrophic” fatigue and “central governor” fatigue theory.2.Recognize that by comparing forearm muscle mass, hand grip, and fatigue that there are relationships between variables which are altered by fatigue. Background. A “catastrophe” fatigue theory has muscle exhaustion and ATP depletion as the main mechanism which would correlate with muscle mass and composition. It is also hypothesized that a brain “central governor” controls muscle activity and that the human body functions as a complex system during exercise until a central brake prevents loss of homeostasis. A “central governor” fatigue theory places the fatigue mechanism in the subconscious brain which ensures homeostasis and protects muscle from damage. The governor “set point” may be altered by illness. Bioelectrical impedance (BIA) estimates of muscle mass are validated against MRI measured muscle mass. The main electron conductor with BIA is muscle. Muscle mass is inversely related to impedance (Z) and directly related to the muscle area (L2). Research objectives. We hypothesized that the relationship between maximum handgrip strength, segmental forearm muscle mass (L2/Z) and fatigue is altered in cancer-related fatigue (CRF) if fatigue is central in origin. Methods. Twenty individuals, ten healthy controls, and ten with CRF were studied. Data collected was: BFI, handgrip x 4 (dominant arm), and forearm BIA impedance. Results. The median total BFI score was 18 for controls and 45 for CRF. In those with CRF relative to healthy controls, there was a poor correlation between BFI and forearm muscle mass, between handgrip strength and BFI, and handgrip strength and muscle mass (Figures1-3, red, healthy controls; blue, CRF). Conclusion. This pilot study demonstrated in those with CRF a poor correlation between handgrip strength, forearm muscle mass and fatigue severity which differed from healthy controls. This suggests that the “central governor” which controls muscle activation is altered in CRF and that fatigue is unlikely to be arising from reduced muscle mass (peripheral fatigue). Implications for research, policy, or practice. Fatigue severity in CRF is unrelated to muscle mass and handgrip strength. Interventions to increase muscle are unlikely to relieve fatigue.

Abstract PA-3: Cancer Fatigue: Does Forearm Muscle Mass and Handgrip Correlate with Fatigue Severity?

Abstract PA-3: Cancer Fatigue: Does Forearm Muscle Mass and Handgrip Correlate with Fatigue Severity?

Greater forearm venous compliance in resistance-trained men

Greater venous compliance is associated with attenuation of the tolerance response to orthostatic stress and reduced incidence of venous diseases. Resistance training induces tolerance to orthostatic challenge and the growth of capillaries, which may lead to negative and positive effects on venous compliance, respectively. It has not been confirmed, however, whether habitual resistance training positively or negatively affects venous compliance. We compared the forearm venous compliance in resistance-trained men with age-matched controls. Eleven resistance-trained middle-aged men (37.7 ± 1.5 years) and 12 age-matched sedentary controls (36.7 ± 1.6 years) were studied. Forearm venous compliance was measured in subjects in the supine position by inflating a venous collecting cuff placed around the upper arm to 60 mmHg for 8 min and then decreasing cuff pressure to 0 mmHg at a rate of 1 mmHg/s. Forearm venous compliance was determined using the first derivative of the pressure-volume relation during cuff pressure reduction (compliance = β(1) + 2β(2) × cuff pressure). Forearm venous compliance at 20 mmHg cuff pressure was 16% greater in the resistance-trained group than in the age-matched sedentary controls (0.097 ± 0.005 vs. 0.083 ± 0.004 ml/dl/mmHg, P < 0.05). Forearm venous compliance was positively related to forearm venous volume (r = 0.643, P = 0.0009), but not forearm muscle mass (r = 0.391, P = 0.0648). In conclusion, the present study suggests that (1) the resistance-trained men have greater forearm venous compliance than age-matched controls, and (2) the higher forearm venous compliance in the resistance-trained men may be explained by greater forearm venous capacitance.

Differential effects of aging on limb blood flow in humans

Aging appears to attenuate leg blood flow during exercise; in contrast, such data are scant and do not support this contention in the arm. Therefore, to determine whether aging has differing effects on blood flow in the arm and leg, eight young (22 +/- 6 yr) and six old (71 +/- 15 yr) subjects separately performed dynamic knee extensor [0, 3, 6, 9 W; 20, 40, 60% maximal work rate (WRmax)] and handgrip exercise (3, 6, 9 kg at 0.5 Hz; 20, 40, 60% WRmax). Arterial diameter, blood velocity (Doppler ultrasound), and arterial blood pressure (radial tonometry) were measured simultaneously at each of the submaximal workloads. Quadriceps muscle mass was smaller in the old (1.6 +/- 0.1 kg) than the young (2.1 +/- 0.2 kg). When normalized for this difference in muscle mass, resting seated blood flow was similar in young and old subjects (young, 115 +/- 28; old, 114 +/- 39 ml x g(-1) x min(-1)). During exercise, blood flow and vascular conductance were attenuated in the old whether expressed in absolute terms for a given absolute workload or more appropriately expressed as blood flow per unit muscle mass at a given relative exercise intensity (young, 1,523 +/- 329; old, 1,340 +/- 157 ml x kg(-1) x min(-1) at 40% WRmax). In contrast, aging did not affect forearm muscle mass or attenuate rest or exercise blood flow or vascular conductance in the arm. In conclusion, aging induces limb-specific alterations in exercise blood flow regulation. These alterations result in reductions in leg blood flow during exercise but do not impact forearm blood flow.

Characteristics And Determinants Of Age-related Changes In Brachial And Popliteal Artery Flow-mediated Dilation In Women

Flow-mediated dilation (FMD) declines in the brachial artery (BA) with healthy aging in women. However, the physiological determinants of this decline are not welled fined, particularly after the BA FMD response has been normalized to the shear stress stimulus. Furthermore, it is not known whether this diminished FMD is seen in the leg vasculature (popliteal artery, PA), a more hemodynamically significant vascular bed utilized during ambulatory activities. PURPOSE To determine the characteristics and determinants of age-related changes in BA and PA FMD in healthy women. METHODS 41 normally active, healthy women (ages 20–79) were measured for variables including cycle VO2peak, body mass index (BMI) and regional muscle mass (forearm and calf). Resting PA and BA diameters and BA shear rate (SR= blood velocity/diameter, an estimate of shear stress) were measured prior to infiation of an upper arm or leg cuff to suprasystolic pressure for 10 min; post-occlusion diameter measurements and peak BA shear rate were used to calculate BA and PA dilation (% D = % change from baseline to peak diameter) and BA % D normalized to shear stimulus (% D/% change in SR from resting to peak). Simple linear regression was used to determine the age-associated changes in BA and PA FMD; forward/reverse stepwise linear regression was then used to determine the predictors of these age-related changes. RESULTS Resting BA and PA diameters did not differ with age (p>0.05). BA FMD normalized to shear stimulus declined 11.6% /decade with age (p <0.01); the strongest predictors of this decline were age, VO2peak, and forearm muscle mass (cumulative r2=.41; p=0.01). PA % D was not related to age (p>0.05). The only significant predictors of PA FMD were calf muscle mass (p=0.03, r2=.112) and BMI (p=0.03; r2=.121). CONCLUSION These results suggest that agerelated changes in the intrinsic dilator capacity of a conduit artery are limb-specific; additionally, the strong predictive ability of forearm flow-mediated dilation does not exist in the calf with predictors such as regional muscle mass and VO2peak. Supported by College of Health and Human Development Seed Grant #423-22

DIETARY CALCIUM ADDS TO THE EXERCISE-ASSOCIATED INCREASE IN FOREARM BUT NOT LEG CORTICAL BONE IN GIRLS

It is not yet clear whether additional dietary calcium intake enhances the exercise training-increase in bone mass. Eighty 4th and 5th grade girls enrolled in a seven-month supervised program of jumping (300 jumps per week at ground reaction forces equivalent to 3–5x body weight) and climbing on a mechanical climber (5 min per week) as part of physical education were randomly assigned to receive (Ex+Snack) or not receive (Ex) calcium-rich snacks containing 450 mg calcium daily. A non-randomized group of 54 girls who received normal P.E. and no snack served as a control group (Controls). Forearm and leg muscle and cortical bone volumetric areas were measured on transaxial images acquired using a Norland/Stratec XCT-2000 peripheral computed tomography unit. The 66% site was used on each limb. Forearm and leg tissue responses are shown in the Table. In the forearm, both Ex and Ex+Snack groups significantly increased muscle mass, but Ex had no change cortical bone. The controls' forearm bone and muscle were unchanged. In the leg, there was a trend toward larger increase in EX and Ex+Snack; however, bone and muscle significantly increased by about 10–14% regardless of group. In conclusion, forearm muscle mass increased in growing girls with exercise but cortical bone increased only in the presence of exercise and increased dietary calcium. In contrast, leg bone and muscle increased and dietary calcium did not further enhance leg cortical bone mass gain.Table

The relationship of peripheral motor nerve conduction velocity to age-associated loss of grip strength.

Age-associated loss of muscle strength is attributed to decreasing muscle mass. Both strength and mass are dependent on peripheral innervation. However, the association between nerve function and age-associated strength loss has not been studied directly. The median nerve contribution to grip strength was estimated using nerve conduction velocity (NCV). Grip strength and NCV were measured in 197 male participants of the Baltimore Longitudinal Study of Aging (age 59.0 +/- 13.9 years). Multiple regression and path analyses were used separately to examine the association between median NCV and grip strength. Grip strength showed a negative quadratic relationship with increasing age (r2 = 0.32, p < 0.001) with a major change in slope occurring after 64.7 years of age. Median NCV (r2 = 0.14, p < 0.001) declined linearly with age. Median NCV significantly contributed to grip strength (p < 0.001) while controlling for forearm muscle mass (forearm circumference), self-reported 24-hour caloric expenditures, and age. The median nerve has an independent contribution to age-associated levels of muscle strength. The level of the effect was smaller than what could be attributed to forearm muscle mass or age.

Wing temperature in flying bats measured by infrared thermography

1. 1. we collected data on the wing temperature of flying bats using infrared thermal imaging to assess the thermoregulatory function of wing membranes. 2. 2. Thermographic images of two Egyptian Fruit Bats, Rousettus aegyptiacus were captured as they flew along a 12 m length of corridor. 3. 3. Body temperature was measured before the first flight and immediately after flight sequences using a rectal thermister probe. 4. 4. Temperatures across the wing ranged from 34°C near the forearm muscle mass, to less than 24°C at the trailing edge (mean ambient temperature 23°C). The majority of the wing was 1–2°C above ambient temperature. 5. 5. We found small, but significant changes in body temperature during flight. These changes did not correlate with changes in wing temperature.

Skeletal muscle response to exercise training in congestive heart failure.

To examine the ability of the skeletal muscle of congestive heart failure (CHF) patients to adapt to chronic exercise, five patients performed localized nondominant wrist flexor training for 28 d. Inorganic phosphate (Pi) and phosphocreatine (PCr) were monitored by magnetic resonance spectroscopy in both forearms at rest and during submaximal wrist flexion exercise at 6, 12, 24, and 36 J.min-1 before and after exercise training. Simultaneous measurements of limb blood flow were made by plethysmography at 12, 24, and 36 J.min-1. Forearm muscle mass and endurance were measured by magnetic resonance imaging and wrist flexion exercise before and after training. The Pi/PCr ratio and pH were calculated from the measured Pi and PCr. Exercise cardiac output, heart rate, plasma norepinephrine, and lactate measured during training were not elevated above resting values, confirming that training was localized to the forearm flexor muscles. After training, muscle bioenergetics, as assessed by the slope of the regression line relating Pi/PCr to submaximal workloads, were improved in the trained forearm of each patient, although muscle mass, limb blood flow, and pH were unchanged. Forearm endurance increased by greater than 260% after training. In the dominant untrained forearm, none of the measured indices were affected. We conclude that localized forearm exercise training in CHF patients improves muscle energetics at submaximal workloads in the trained muscle, an effect which is independent of muscle mass, limb blood flow, or a central cardiovascular response during training. These findings indicate that peripheral muscle metabolic and functional abnormalities in CHF can be improved without altering cardiac performance.