vendex and Overweight

Exercise training (EX) and weight loss (WL) improve lower extremity physical function (LEPF) in older overweight women; however, effects on rate of torque development (RTD) are unknown. This study aimed to determine the effects of WL + EX or WL alone on RTD, and relatedly LEPF, in overweight older women. Leg strength was assessed using isokinetic dynamometry, and RTD was calculated (RTD200 = RTD at 200 ms, RTDPeak = peak RTD, T2P = time to 1st peak). LEPF was determined via clinical functional tasks. Women (n = 44, 69.1 ± 3.6 years, 30.6 ± 4.3 kg/m2) completed a 6-month trial in EX + WL or WL groups with similar weight loss (-9.8 ± 4.2%, p > .95). EX + WL had greater improvements in (a) most LEPF tasks (p < .001) and (b) RTD200, compared with WL (36% vs. -16%, p = .031); no other RTD parameters differed. Changes in RTD parameters and LEPF were not related (all p > .05). RTD is responsive to EX but is not associated with LEPF in older women.

Topics: Aged; Exercise; Female; Humans; Muscle Strength; Overweight; Torque; Weight Loss

Children who are overweight typically do not perform motor skills as well as normal-weight peers. This study examined whether vertical jump kinetics and kinematics of children who are overweight differ from nonoverweight peers.. Thirty-nine children completed maximum-effort countermovement vertical jumps. Motion capture was used to complete lower extremity kinematic and kinetic analyses.. The overweight group (body mass index ≥ 85th percentile; N = 11; age = 6.5 [1.6] y) jumped lower relative to their mass (0.381 cm/kg lower; P < .001) than normal-weight peers (N = 28; age = 6.4 [1.7] y). Compared with children who are normal weight, children who were overweight exhibited a shallower countermovement (knee: 12° less flexion, P = .02; hip: 10° less flexion, P = .045), lower hip torque (0.06 N·m/kg lower, P = .01) and hip work (40% less work, P = .01), and earlier peak joint angular velocities (knee: 9 ms earlier, P = .001; hip: 14 ms earlier, P = .004).. Children who are overweight do not achieve optimal jumping mechanics and exhibit jumping characteristics of an earlier developmental stage compared with their peers. Interventions should help children who are overweight learn to execute a proper countermovement.

Topics: Biomechanical Phenomena; Child; Child, Preschool; Exercise Test; Female; Humans; Kinetics; Lower Extremity; Male; Movement; Overweight; Range of Motion, Articular; Torque

What is the central question of this study? What is the time course of muscular adaptations to short-duration resistance exercise training? What is the main finding and its importance? Short-duration resistance training results in early and progressive increases in muscle mass and function and an increase in insulin sensitivity.. The aim of the study was to investigate the effects of 6 weeks of resistance exercise training, composed of one set of each exercise to voluntary failure, on insulin sensitivity and the time course of adaptations in muscle strength/mass. Ten overweight men (age 36 ± 8 years; height 175 ± 9 cm; weight 89 ± 14 kg; body mass index 29 ± 3 kg m

Topics: Adaptation, Physiological; Adult; Body Mass Index; Exercise; Humans; Insulin Resistance; Knee; Knee Joint; Male; Muscle Strength; Muscle, Skeletal; Overweight; Resistance Training; Time Factors; Torque

Underfat individuals have been neglected as a malnourished population in terms of redox homeostasis. The aim of the present study was to evaluate the effect of body composition on redox homeostasis at rest and in response to exercise. Underfat, lean and overfat women, classified according to their BMI and body fat percentage, participated in the study and were subjected to an acute session of eccentric exercise. With regard to muscle function and damage, a significant group × time interaction was found for range of motion (

Topics: Biomarkers; Body Fat Distribution; Body Mass Index; Creatine Kinase; Energy Metabolism; Exercise; Female; Homeostasis; Humans; Isometric Contraction; Knee; Muscle, Skeletal; Myalgia; Overweight; Oxidation-Reduction; Range of Motion, Articular; Rest; Thinness; Torque; Young Adult

The influence of overweight, as a precursor to obesity, was analyzed on the elastic properties of the triceps surae. Based on body mass index (BMI), children (9 years ± 4 mo) were classified as control (CON; n = 23; BMI -1SD>Z score<1SD) or overweight (OW; n = 21, BMI 1SD>Z score<3SD) with regard to reference data from the World Health Organization. Musculotendinous (MT) stiffness of the series elastic component (SEC) was determined using quick-release tests to obtain 1) the MT stiffness index from the slope of either linear stiffness-torque (SI(MT-Torque)) or stiffness-EMG (SI(MT-EMG)) relationships and 2) passive stiffness from the intercept point with the ordinate. Finally, the SEC active (α(0)) and passive fractions (C(passive)) were separated as described by Morgan (Am J Physiol, 1977), using alpha-torque (α(0-Torque,) C(passive-Torque)) or alpha-EMG (α(0-EMG,) C(passive-EMG)) relationships. No significant differences in SI(MT-Torque) or α(0-Torque) were observed between OW and CON. SI(MT-EMG) or α(0-EMG) values were significantly different between OW and CON, which indicate an increase in MT stiffness. In all cases, passive stiffness (K(p), C(passive-torque), C(passive-EMG)) was significantly greater in OW but independent of the activation capacities. These results indicate that a weight-related additional loading of the MT structures in OW children caused the MT system to response accordingly to the functional demand, i.e., higher stiffness of the MT structures due to a concomitant increase in the stiffness of the SEC passive and active fraction. This study also reveals that possible differences in the activation capacities influence the determination of MT stiffness of the SEC active fraction.

Topics: Ankle Joint; Anthropometry; Body Mass Index; Child; Elasticity; Female; Humans; Male; Muscle Contraction; Muscle, Skeletal; Musculoskeletal Physiological Phenomena; Overweight; Torque

The purpose of this study was to determine if excess fat negatively affects relative strength and walking gait performance in overweight, older women. Twenty-five older women (65-80 yr) were separated into normal weight (BMI<25 kg m(-2), n=11) and overweight groups (BMI 25 ≥ kg m(-2), n=14). Strength and rate of torque development (RTD) of the knee extensors and flexors, ankle plantarflexors and dorsiflexors were measured. Participants walked at standard and maximal speeds during which muscle activation, spatiotemporal and kinetic gait variables were measured. Relative to mass, overweight older women had 24% lower maximal torque and 38% lower RTD than normal weight women. Maximal walking speed was slower in overweight (1.25±0.22 vs. 1.54±0.25 m s(-1), P=0.004) and was correlated to strength (r=0.53, P<0.01) and fat mass (r=-0.65, P=0.001). At maximal speed, overweight had 11% lower vertical ground reaction force relative to mass, 8% slower stride rate, 12% shorter strides, 13% longer foot-ground contact times, 21% longer double-limb support times, 65% greater knee extensor and 78% greater plantarflexor activation (P<0.05). Overweight, older women demonstrated altered gait and reduced walking performance related to poor relative strength and rate of torque development of lower-extremity muscles.

Topics: Aged; Aged, 80 and over; Body Fat Distribution; Body Mass Index; Electromyography; Female; Gait; Humans; Lower Extremity; Muscle Strength; Muscle, Skeletal; Overweight; Torque; Walking