Changes in muscle thickness of gastrocnemius and soleus associated with age and sex.
ABSTRACT Gastrocnemius and soleus in the triceps surae have functional and histological differences.We therefore investigated age-related changes in muscle thickness of these two muscles, as well as the difference in these changes between men and women.
Participants comprised 847 healthy adults aged 20 to 79 years. A B-mode ultrasound scanner, with participants sitting on a chair, was used to measure muscle thickness from the midpoint of the gastrocnemius medialis muscle at the level of maximum girth (target point). The ratio of muscle thickness to height was calculated. The inter-rater and intra-rater reliability of measuring muscle thickness with the ultrasound scanner and the validity of the target point were demonstrated before the examination.
Gastrocnemius was significantly thinner in women aged 60 or older and in men aged 50 or older, compared with their counterparts in their 20s. For soleus, no significant differences in thickness were found among the age groups in either sex. Decline in muscle thickness from age 40-79 was greater for gastrocnemius than for soleus.
These results confirm that gastrocnemius starts to deteriorate earlier and atrophies at a faster pace than soleus. A significant sex difference was found only in the onset age of gastrocnemius deterioration, which was earlier in men than in women.
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ABSTRACT: Sex and age are reported to influence the maximal dynamometric performance of major muscle groups, inclusive of ankle plantar-flexors. Knee flexion (KF) also impacts plantar-flexion function from where stems utilization of 0° and 45° of KF for clinical assessment of gastrocnemius and soleus, respectively. The influence of KF, sex and age on dynamometric indicators of plantar-flexion fatigue was examined in 28 males and 28 females recruited in two different age groups (above and below 40 years). Each subject performed 50 maximal concentric isokinetic plantar-flexions at 60 deg·s with 0° and 45° of KF. Maximal voluntary isometric contractions were determined before and after isokinetic trials; and maximal, minimal and normalized linear slopes of peak power during testing. Main effects of and two-way interactions between KF, sex, age and order of testing were explored using mixed-effect models and stepwise regressions. At 0° and 45°, the fatigue indicators in younger and older individuals were similar and not influenced by testing order. However, peak isokinetic power and isometric torque declined to greater extents in males than females and, moreover, KF exerted greater impacts on the absolute plantar-flexion performance and maximal-to-minimal reduction in isokinetic power in males. Because KF wielded no pronounced effect on fatigue indicators, this test may perhaps be used over time with no major concern regarding the exact knee angle. Our findings indicate that sex, rather than age, should be considered when interpreting dynamometric indicators of fatigue from repeated maximal concentric isokinetic plantar-flexions, e.g., when establishing normative values or comparing outcomes.The Journal of Strength and Conditioning Research 11/2013; · 1.80 Impact Factor
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ABSTRACT: The present study investigated whether a combination of the thickness and hardness of muscles without muscle tension can be used to estimate muscle strength during knee extension in adult males and females. Seventy-two males and thirty-three females, whose ages ranged from 18 to 35 years, participated in this study. We measured muscle thickness and hardness in the right anterior region of the thigh (rectus femoris muscle and vastus intermedius muscle) without muscle tension using an ultrasound muscle hardness meter, and the maximal voluntary isometric contraction of right knee extension (MVIC). The changing ratios (%) of the tissue thickness before compression to those during compression (compression ratio) are calculated as an index of the hardness. Higher ratio indicates a harder muscle compared with that of other individuals showing the same muscle thickness. In male group, although the MVIC had significantly positive correlation to both muscle thickness (r=0.412, p<0.01) and compression ratio (r=0.233, p<0.05), their variables also had correlation mutually. In the female group, the MVIC has significantly positive correlation to only compression ratio (r=0.499, p<0.01), not muscle thickness (r=0.225, n.s.). On multiple linear regression analysis, the combination of two parameters (muscle thickness and compression ratio) allowed more accurate estimation of MVIC (r=0.573, p<0.01) in the female group. These findings suggested that the combination of muscle thickness and hardness is capable of effectively estimating muscle strength especially in females.SpringerPlus 01/2013; 2:457.
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ABSTRACT: Human adult aging is associated with a loss of strength, contractile velocity and hence, power. The principal plantar flexors, consisting of the bi-articular gastrocnemeii and the mono-articular soleus, appear to be affected differently by the aging process. However, the age-related effect of knee joint angle on the torque-angular velocity relationship and power production of this functionally important muscle group is unknown. The purpose was to determine whether flexing the knee, thereby reducing the gastrocnemius contribution to plantar flexion, would exacerbate the age-related decrements in plantar flexion power, or shift the torque-angular velocity relationship differently in older compared with young men. Neuromuscular properties were recorded from 10 young (~25 y) and 10 old (~78 y) men with the knee extended (170º) and flexed (90º), in a randomized order. Participants performed maximal voluntary isometric contractions (MVCs), followed by maximal velocity-dependent shortening contractions at pre-set loads, ranging from 15 to 75% MVC. The young men were ~20-25% stronger, ~12% faster and ~30% more powerful than the old for both knee angles (P<0.05). In both age groups, isometric MVC torque was ~17% greater in the extended than flexed knee position, with no differences in voluntary activation (>95%). The young men produced 7-12% faster angular velocities in the extended knee position for loads ≤30% MVC, but no differences at higher loads; whereas there were no detectable differences in angular velocity between knee positions in the old across all relative loads. For both knee angles, young men produced peak power at 43.3±9.0% MVC, whereas the old men produced peak power at 54.8±7.9% MVC. These data indicate the young, who have faster contracting muscles compared with the old, can rely more on velocity than torque for generating optimal power.Experimental gerontology 01/2014; · 3.34 Impact Factor