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The purpose of this study is to provide a force-velocity (F-V) equation that combines a linear and a hyperbolic region, and to compare its derived results to those obtained from linear equations. A total of 10 cross-training athletes and 14 recreationally resistance-trained young men were assessed in the unilateral leg press (LP) and bilateral bench press (BP) exercises, respectively. F-V data were recorded using a force plate and a linear encoder. Estimated maximum isometric force (F

Iliotibial band syndrome (ITBS) is presumably caused by excessive tension in the iliotibial band (ITB) leading to compression and inflammation of tissues lying beneath it. Usually managed conservatively, there is a lack of scientific evidence supporting the treatment recommendations, and high symptom recurrence rates cast doubt on their causal effectiveness. This review discusses the influence of common physiotherapeutic measures on risk factors contributing to tissue compression beneath the ITB.The potential pathogenic factors are presented on the basis of a simple biomechanical model showing the forces acting on the lateral aspect of the knee. Existent literature on the most commonly prescribed physiotherapeutic interventions is critically discussed against the background of this model. Practical recommendations for the optimization of physiotherapy are derived.According to biomechanical considerations, ITBS may be promoted by anatomical predisposition, joint malalignments, aberrant activation of inserting muscles as well as excessive ITB stiffness. Hip abductor strengthening may correct excessive hip adduction but also increase ITB strain. Intermittent stretching interventions are unlikely to change the ITB's length or mechanical properties. Running retraining is a promising yet understudied intervention.High-quality research directly testing different physiotherapeutic treatment approaches in randomized controlled trials is needed.

Background It is important for sport scientists and health professionals to have estimative methods for energy demand during diferent physical activities. The metabolic equivalent of task (MET) provides a feasible approach for classifying activity intensity as a multiple of the resting metabolic rate (RMR). RMR is generally assumed to be 3.5 mL of oxygen per kilogram of body mass per minute (mL O2 kg−1 min−1), a value that has been criticized and considered to be overestimated in the older adult population. However, there has been no comprehensive efort to review available RMR estimations, equivalent to 1 MET, obtained in the older adult population. Objective The aim of this review was to examine the existing evidence reporting measured RMR values in the older adult population and to provide descriptive estimates of 1 MET. Methods A systematic review was conducted by searching PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus, and Cochrane Library, from database inception to July 2021. To this end, original research studies assessing RMR in adults≥60 years old using indirect calorimetry and reporting results in mL O2 kg−1 min−1 were sought. Results Twenty-three eligible studies were identifed, including a total of 1091 participants (426 men). All but two studies reported RMR values lower than the conventional 3.5 mL O2 kg−1 min−1. The overall weighted average 1 MET value obtained from all included studies was 2.7±0.6 mL O2 kg−1 min−1; however, when considering best practice studies, this value was 11% lower (2.4±0.3 mL O2 kg−1 min−1). Conclusion Based on the results of this systematic review, we would advise against the application of the standard value of 1 MET (3.5 mL O2 kg−1 min−1) in people ≥ 60 years of age and encourage the direct assessment of RMR using indirect calorimetry while adhering to evidence-based best practice recommendations. When this is not possible, assuming an overall value of 2.7 mL O2 kg−1 min−1 might be reasonable. Systematic review registration: International Prospective Register of Systematic Reviews on 30 September 2020, with registration number CRD42020206440.

This study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen's d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p0.001), but no other blood markers increased (all, p0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.This study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen’s d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p0.001), but no other blood markers increased (all, p0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.

Background: The 30-s sit-to-stand (STS) muscle power test is a valid test to assess muscle power in older people; however, whether it may be used to assess trajectories of lower-limb muscle power through the adult lifespan is not known. This study evaluated the pattern and time course of variations in relative, allometric and specific STS muscle power throughout the lifespan. Methods: Subjects participating in the Copenhagen Sarcopenia Study (729 women and 576 men; aged 20 to 93 years) were included. Lower-limb muscle power was assessed with the 30-s version of the STS muscle power test. Allometric, relative and specific STS power were calculated as absolute STS power normalized to height squared, body mass and leg lean mass as assessed by DXA, respectively. Results: Relative STS muscle power tended to increase in women (0.08 ± 0.05 W⋅kg− 1 ⋅yr− 1 ; p = 0.082) and increased in men (0.14 ± 0.07 W⋅kg− 1 ⋅yr− 1 ; p = 0.046) between 20 and 30 years, followed by a slow decline (− 0.05 ± 0.05 W⋅kg− 1 ⋅yr− 1 and − 0.06 ± 0.08 W⋅kg− 1 ⋅yr− 1 , respectively; both p > 0.05) between 30 and 50 years. Then, relative STS power declined at an accelerated rate up to oldest age in men (− 0.09 ± 0.02 W⋅kg− 1 ⋅yr− 1 ) and in women until the age of 75 (− 0.09 ± 0.01 W⋅kg− 1 ⋅yr− 1 ) (both p < 0.001). A lower rate of decline was observed in women aged 75 and older (− 0.04 ± 0.02 W⋅kg− 1 ⋅yr− 1 ; p = 0.039). Similar age-related patterns were noted for allometric and specific STS power. Conclusions: The STS muscle power test appears to provide a feasible and inexpensive tool to monitor cross sectional trajectories of muscle power throughout the lifespan.

Purpose: This study aimed to compare the effects of four resistance training (RT) programs with different velocity loss (VL) thresholds: 0% (VL0), 10% (VL10), 20% (VL20) and 40% (VL40) on sprint and jump performance, muscle strength, neuromuscular, muscle hypertrophy and architectural adaptations. Methods: Sixty-four young resistance-trained men were randomly assigned into four groups (VL0, VL10, VL20, and VL40) that differed in the VL allowed in each set. Subjects followed an RT program for 8 weeks (2 sessions per week) using the full-squat (SQ) exercise, with similar relative intensity (70-85% 1RM), number of sets (3) and inter-set recovery period (4-min). Before and after the RT program the following tests were performed: 1) muscle hypertrophy and architecture of the vastus lateralis (VLA); 2) tensiomyography; 3) 20-m running sprint; 4) vertical jump; 5) maximal voluntary isometric contraction in SQ; 6) progressive loading test in SQ; and 7) fatigue test. Results: No between-group differences existed for RT-induced gains in sprint, jump and strength performance despite the differences in the total volume performed by each group. VL20 and VL40 showed significant increases (P < 0.001) in muscle hypertrophy (group × time interaction, P = 0.06). However, only VL40 exhibited a significant slowing (P < 0.001) of the delay time in the VLA muscle (group × time interaction: P = 0.05). Moreover, VL40 showed a significant decrease in the early rate of force development (P = 0.04). Conclusions: Higher VL thresholds (i.e. VL20 and VL40) maximized hypertrophic adaptations, although an excessive VL during the set (i.e. VL40) may also induce negative neuromuscular adaptations. Therefore, moderate VL thresholds should be chosen to maximize strength adaptations and to prevent negative neuromuscular adaptations.

La carrera descalza ha sido ampliamente estudiada últimamente, pero poco se sabe de cambios anatómicos que produce en el pie. El objetivo de este estudio fue determinar estos cambios producidos de forma aguda y a largo plazo en sujetos que entrenan a pie descalzo. 29 sujetos divididos en dos grupos: Barefoot (BFGr) (n=17) y Shod (SGr) (n=12), realizaron un protocolo de efecto agudo consistente en correr durante 20 min sobre treadmill a 3.1 m/s y un protocolo de entrenamiento de 8 semanas de carrera de resistencia con aumento progresivo de volumen. BFGr realizó todas las sesiones a pie descalzo. Al finalizar cada protocolo se midió Foot Length (FL), Forefoot Width (FW), Hindfoot Width (HW), Navicular Height (NH), Arch Index (AI) y Maximum Surface (MS). Se efectuó ANOVA 3x2 para comprobar los efectos que el tiempo y la condición de calzado produjo. La condición de calzado produjo efectos significativos sobre todas las variables (FL: p=0.000, 2 p=0.997; FW: p=0.000, 2 p=0,997; HW: p=0.000, 2 p= 0,994; NH: p=0.000, 2 p=0.953;AI: p=0.000, 2 p=0.898; MS: p=0.000, 2 p=0.983) y el factor tiempo sobre AI (p=0.012, 2 p=0.152) y MS (p=0.000, 2 p=0.259). Hubo interacción significativa Tiempo x Condición en FW (p=0.036, 2 p= 0.116) y NH (p=0.019, 2 p= 0.143). MS aumen tó luego del protocolo de efecto agudo (p=0.000) y a largo plazo (p=0.001) en BFGr. El porcentaje de sujetos con pie normal aumentó en BFGr y con pie plano aumentó en SGr. El entrenamiento de carrera a pie descalzo produce efectos, principalmente luego de un período de adaptación de 8 semanas, tendientes a un aumento armónico en la superficie de apoyo plantar con tendencia a una disminución relativa del área del mediopié, lo cual se tradujo en una disminución de sujetos con arco plantar de tipología plana.

Introduction and Purpose Physical activity (PA) is considered the best nonpharmacological treatment for the decrease in bone mass (BM) produced during aging. Therefore, it is essential to assess how the time spent in PA is distributed to control further changes. This work examines the relationship between movement behaviors and BM during aging, using compositional data analysis. Methods We studied 227 older people 65 to 94 yr old (102 men and 125 women), divided by sex and bone status, over a period of 4 yr. Time spent in sedentary behavior (SB), light PA (LPA), and moderate to vigorous PA (MVPA), was assessed using accelerometry. BM was determined by dual-energy x-ray absorptiometry. Results The changes in MVPA were positively associated with the rate of BM decay at spine and leg in the whole sample and men’s subgroup (P ≤ 0.05). In women, the rate of BM decay at spine and Ward’s triangle were negatively associated with SB changes, and BM decay at femoral neck and Ward’s triangle were positively associated with LPA (P ≤ 0.05). Conclusion Increasing MVPA related to other movement behaviors produces improvements in the rate of bone change in older men, whereas to increase LPA and maintain MVPA would be the best approach to enhance BM in older women.

PURPOSE: Being able to rise from a chair is paramount for independent living and is strongly influenced by the ability of the lower limbs to exert mechanical power. This study assessed minimal thresholds of lower-limb relative muscle power required to perform the sit-to-stand (STS) task in older adults and its association with mobility limitations and disability. METHODS: A total of 11,583 older adults (age, 60-103 yr) participated in this investigation. The 5-rep and 30-s versions of the STS test were used to assess chair rising ability. Relative power was calculated by the STS muscle power test. The minimum thresholds of power required to perform the STS tests were derived from the minimum values (i.e., "floor" effect) reported in the power tests through regression analyses. Mobility limitations and disability in activities of daily living (ADL) were recorded. RESULTS: For the average older man and woman, the thresholds to complete five STS repetitions were 1.1 and 1.0 W·kg-1, respectively, whereas the thresholds to complete one STS repetition were 0.3 W·kg-1 in both sexes. These thresholds increased linearly with height (5- and 1-rep, respectively: +0.13 and +0.03 W·kg-1 per 10-cm increase; both P < 0.001) and did not differ by sex or testing condition (both P ≥ 0.259). All participants with relative power below the 5-rep threshold presented mobility limitations, and 51%-56% of women and 36%-49% of men also showed disability in ADL (all χ2 ≥ 290.4; P < 0.001). CONCLUSION: A minimum level of relative muscle power is required to rise from a chair independently, which depends on the individual height and is associated with increased mobility limitations and disability. This information will help interpret data yielded by the STS muscle power test and may contribute to the prevention and treatment of mobility limitations in older people. ispartof: MEDICINE & SCIENCE IN SPORTS & EXERCISE vol:53 issue:11 pages:2217-2224 ispartof: location:United States status: published

Our STS power equation does not aim to substitute “gold standard” methods, and does not provide data that can be interchangeable with those yielded by comprehensive kinematic and kinetic analyses; however, it provides the possibility to assess lower-limb muscle power in contexts in which time or resources constrains inherent to traditional instruments may prevent its assessment.

This study aimed to determine the specific adaptations provoked by power oriented resistance training using light (LL-PT, 40% 1-RM) vs. heavy (HL-PT, 80% 1-RM) loads in older adults. Using a randomized within-subject study design, 45 older adults (>65 years) completed an 8-week control period (CTR) followed by 12 weeks of unilateral LL-PT vs. HL-PT on a leg press. The 1-RM, theoretical force at zero velocity (F0), maximal unloaded velocity (V0), and maximal muscle power (Pmax) were determined through a force-velocity relationship test. Isometrically, the rate of force development (RFD) and the corresponding muscle excitation of the knee extensor muscles were assessed. In addition, muscle cross-sectional area (CSA) and architecture of two quadriceps muscles were determined. Changes after CTR, LL-PT and HL-PT were compared using linear mixed models. HL PT provoked greater improvements in 1-RM and F0 (effect size (ES) = 0.55‒0.68; p < 0.001) than those observed after LL-PT (ES = 0.27−0.47; p ≤ 0.001) (post hoc treatment effect, p ≤ 0.057). By contrast, ES of changes in V0 was greater in LL-PT compared to HL-PT (ES = 0.71, p < 0.001 vs. ES = 0.39, p < 0.001), but this differ ence was not statistically significant. Both power training interventions elicited a moderate increase in Pmax (ES = 0.65‒0.69, p < 0.001). Only LL-PT improved early RFD (ie, ≤100 ms) and muscle excitation (ES = 0.36‒0.60, p < 0.05). Increased CSA were noted after both power training programs (ES = 0.13‒0.35, p < 0.035), whereas pennation angle increased only after HL-PT (ES = 0.37, p = 0.004). In conclusion, HL-PT seems to be more effective in improving the capability to gen erate large forces, whereas LL-PT appears to trigger greater gains in movement velocity in older adults. However, both interventions promoted similar increases in muscle power as well as muscle hypertrophy.

ObjectivesTo assess the influence of muscle power and adiposity on all-cause mortality risk and to evaluate the ‘fat but powerful’ (F+P) (or ‘fat but fit’) paradox in older adults.MethodsA total of 2563 older adults (65‒91 years old) from the EXERNET multicentre study were included. Adiposity (body mass index (BMI), waist circumference, body fat percentage (BF%) and fat index), allometric and relative power (sit-to-stand muscle power test) and various covariates (age, sex, hypertension, smoking status and walking and sitting times per day) were registered at baseline. All-cause mortality was recorded during a median follow-up of 8.9 years. Participants were classified into four groups: lean and powerful (L+P), F+P, lean but weak and fat and weak (F+W). Cox proportional hazard regression models and adjusted HRs were calculated.ResultsAccording to BMI and waist circumference, all-cause mortality risk was reduced in the F+P (HR=0.55 and 0.63, p=0.044 and 0.049, respectively) and L+P (HR=0.57 and 0.58, p=0.043 and 0.025, respectively) groups. According to BF%, all-cause mortality decreased in the L+P group (HR=0.53; p=0.021), and a trend for a reduction was reported in the F+P group (HR=0.57; p=0.060). According to fat index, a survival benefit was only noted in the L+P group (HR=0.50; p=0.049). Higher levels of relative power reduced all-cause mortality risk among older people (HR=0.63 and 0.53, p=0.006 and 0.011, respectively).ConclusionPowerful older people exhibited a reduced 9-year all-cause mortality regardless of BMI, waist circumference and BF%. Obesity according to fat index blunted the survival benefits of being powerful.

BackgroundPower-oriented resistance training (PRT) is one of the most effective exercise programs to counteract neuromuscular and physical function age-related declines. However, the optimal load that maximizes these outcomes or the load-specific adaptations induced on muscle power determinants remain to be better understood. Furthermore, to investigate whether these adaptations are potentially transferred to an untrained limb (i.e., cross-education phenomenon) could be especially relevant during limb-immobilization frequently observed in older people (e.g., after hip fracture).MethodsAt least 30 well-functioning older participants (>65 years) will participate in a within-person randomized controlled trial. After an 8-week control period, the effects of two 12-week PRT programs using light vs. heavy loads will be compared using an unilateral exercise model through three study arms (light-load PRT vs. non-exercise; heavy-load PRT vs. non-exercise; and light- vs. heavy- load PRT). Muscle-tendon function, muscle excitation and morphology and physical function will be evaluated to analyze the load-specific effects of PRT in older people. Additionally, the effects of PRT will be examined on a non-exercised contralateral limb.DiscussionTailored exercise programs are largely demanded given their potentially greater efficiency preventing age-related negative consequences, especially during limb-immobilization. This trial will provide evidence supporting the use of light- or heavy-load PRT on older adults depending on individual needs, improving decision making and exercise program efficacy.Clinical Trial RegistrationNCT03724461 registration data: October 30, 2018.

Background: The purposes of this study were: i) to evaluate the association of sit-to-stand (STS) power and body composition parameters [body mass index (BMI) and legs skeletal muscle index (SMI)] with age; ii) to provide cut-off points for low relative STS power (STSrel), ii) to provide normative data for well-functioning older adults and iv) to assess the impact of low STSrel on negative outcomes.Methods: Cross-sectional design (1369 older adults). STS power parameters assessed by validated equations, BMI and Legs SMI assessed by dual-energy X-ray absorptiometry were recorded. Sex- and age-adjusted segmented and logistic regression analyses and receiver operator characteristic curves were used.Results: Among men, STSrel showed a negative association with age up to the age of 85 years (‒1.2 to ‒1.4%year-1; pyear-1; prel were 2.5 W∙kg-1 in men and 1.9 W∙kg-1 in women. Low STSrel was associated with frailty (OR[95%CI]= 5.6 [3.1, 10.1]) and low habitual gait speed (HGS) (OR[95%CI]= 2.7 [1.8, 3.9]) in men while low STSrel was associated with frailty (OR[95%CI]= 6.9 [4.5, 10.5]) low HGS (OR[95%CI]= 2.9 [2.0, 4.1]), disability in activities of daily living (OR[95%CI]= 2.1 [1.4, 3.2]), and low quality of life (OR[95%CI]= 1.7 [1.2, 2.4]) in women. Conclusions: STSrel declined with increasing age in both men and women. Due to the adverse outcomes related to STSrel, the reported cut-off points can be used as a clinical tool to identify this condition among older adults.

ObjectivesTo assess the influence of muscle power and adiposity on all-cause mortality risk and to evaluate the ‘fat but powerful’ (or ‘fat but fit’) paradox in older adults.MethodsA total of 2563 older adults (65‒91 years old) from the EXERNET Multi-center study were included. Adiposity (body mass index (BMI), waist circumference, body fat percentage (BF%) and fat index), allometric and relative power (sit-to-stand muscle power test) and various covariates (age, sex, hypertension, smoking status, and walking and sitting times per day) were registered at baseline. All-cause mortality was recorded during a median follow-up of 8.9 years. Participants were classified into four groups: lean and powerful (L+P), fat but powerful (F+P), lean but weak (L+W) and fat and weak (F+W). Cox proportional hazard regression models and adjusted hazard ratios (HR) were calculated.ResultsAccording to BMI and waist circumference, all-cause mortality risk was reduced in the F+P (HR=0.55 and 0.63, respectively; p≤0.049) and L+P (HR=0.57 and 0.58, respectively; p≤0.043) groups. According to BF%, all-cause mortality decreased in the L+P group (HR=0.53; p=0.021), and a trend for a reduction was reported in the F+P group (HR=0.57; p=0.060). According to fat index, a survival benefit was only noted in the L+P group (HR=0.50; p=0.049). Higher levels of relative power reduced all-cause mortality risk among older people (HR=0.63 and 0.53, respectively; p≤0.011).ConclusionPowerful older people exhibited a reduced 9-year all-cause mortality regardless of BMI, waist circumference and BF%. Obesity according to fat index blunted the survival benefits of being powerful.

Purpose: This study aimed to compare the adaptations provoked by various velocity loss (VL) thresholds used in resistance training on the squat force–velocity (F–V) relationship. Methods: Sixty-four resistance-trained young men were randomly assigned to one of four 8-week resistance training programs (all 70%–85% 1-repetition maximum) using different VL thresholds (VL0 = 0%, VL10 = 10%, VL20 = 20%, and VL40 = 40%) in the squat exercise. The F–V relationship was assessed under unloaded and loaded conditions in squat. Linear and hyperbolic (Hill) F–V equations were used to calculate force at zero velocity (F0), velocity at zero force (V0), maximum muscle power (Pmax), and force produced at mean velocities ranging from 0.0 to 2.0 m·s−1. Changes in parameters derived from the F–V relationship were compared among groups using linear mixed models. Results: Linear equations showed increases in F0 (120.7 N [89.4 to 152.1]) and Pmax (76.2 W [45.3 to 107.2]) and no changes in V0 (−0.02 m·s−1 [−0.11 to 0.06]) regardless of VL. Hyperbolic equations depicted increases in F0 (120.7 N [89.4 to 152.1]), V0 (1.13 m·s−1 [0.78 to 1.48]), and Pmax (198.5 W [160.5 to 236.6]) with changes in V0 being greater in VL0 and VL10 versus VL40 (both P −1 (all P −1. Conclusions: All groups improved linear and hyperbolic F0 and Pmax and hyperbolic V0 (except VL40). The dose–response relationship exhibited an inverted U-shape pattern at velocities ≤0.5 m·s−1 with VL10 and VL20 showing the greatest standardized changes.

McArdle disease (glycogenosis-V) is associated with exercise intolerance, however, how it affects an important marker of cardiometabolic health as it is adiposity remains unknown. We evaluated the association between physical activity (PA) and adiposity in patients with McArdle disease. We assessed 199 adults of both sexes (51 McArdle patients (36 &plusmn, 11 years) and 148 healthy controls (35 &plusmn, 10 years)). Body fat (BF) was determined using dual-energy X-ray absorptiometry (DXA) method and each patient&rsquo, s PA was assessed with the International PA Questionnaire (IPAQ). Although body mass index values did not differ between patients and controls, McArdle patients had significantly higher values of BF in all body regions (p &lt, 0.05) and higher risk of suffering obesity (odds ratio (OR): 2.54, 95% confidence interval (95% CI): 1.32&ndash, 4.88). Male patients had higher BF and obesity risk (OR: 3.69, 95% CI: 1.46&minus, 9.34) than their sex-matched controls, but no differences were found within the female sex (p &lt, 0.05). In turn, active female patients had lower trunk BF than their inactive peers (p &lt, 0.05). Males with McArdle seem to have adiposity problems and a higher risk of developing obesity than people without the condition, while female patients show similar or even better levels in the trunk region with an active lifestyle. Therefore, special attention should be given to decrease adiposity and reduce obesity risk in males with McArdle disease.

OBJECTIVE This study aimed to compare the effects of four velocity-based training (VBT) programs in bench press (BP) between a wide range of velocity loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy. METHODS Sixty-four resistance-trained young men were randomly assigned into four groups (VL0, VL15, VL25, and VL50) that differed in the VL allowed in each set. Subjects followed a VBT program for 8-weeks using the BP exercise. Before and after the VBT program the following tests were performed: (a) cross-sectional area (CSA) measurements of pectoralis major (PM) muscle; (b) maximal isometric test; (c) progressive loading test; and (d) fatigue test. RESULTS Significant group x time interactions were observed for CSA (P

Spinal cord injury (SCI) derives in loss of bone mineral content (BMC) and bone mineral density (BMD). However, physical activity is an important determinant in bone mass acquisition, which is partially mediated through the lean mass (LM). The aim was to examine the effect of cardiorespiratory fitness (CRF) on BMD and BMC arms of adult males with SCI and able-bodied controls using the arm LM as a mediator variable. Thirty able-bodied men and thirty men with SCI participated. BMC and BMD were analysed by DXA, and indirect calorimetry was used to calculate VO

Objectives: This study aimed i) to compare relative sit-to-stand power (STSrel) values yielded by the different equations reported in the literature; ii) to examine the associations between STSrel, derived from the equations, and age, sex, frailty and habitual gait speed (HGS); and iii) to compare the ability of the different STSrel equations to detect frailty and low HGS in older adults. Methods: 1568 participants (>65 years) were included. STSrel was calculated according to four validated equa tions. Frailty was assessed using the Frailty Trait Scale and HGS as the time to complete 3 m. ANOVA tests, regression analyses and receiver operator characteristic curves were used. Results: There were significant differences among the STSrel values yielded by all the equations, which were higher in men compared to women and negatively associated with age (r = − 0.21 to − 0.37). STSrel was posi tively and negative associated to HGS and frailty, respectively, in both men (r = 0.29 to 0.36 and r = − 0.18 to − 0.45) and women (r = 0.23 to 0.45 and r = − 0.09 to − 0.57) regardless of the equation used. Area under the curve values varied between 0.68 and 0.80 for Alcazar's, 0.67–0.80 for Ruiz-Cardenas's, ´ 0.51–0.65 for Smith's, and 0.68–0.80 for Takai's equations. Low STSrel indicated an increased probability of having both low HGS and frailty (OR [95%CI] = 1.6 to 4.5 [1.21 to 5.79]) for all equations with the exception of Smith's equations for frailty in women. Conclusions: All the equations presented adequate criterion validity, however, the Alcazar's equation showed the highest level of clinical relevance according to its ability to identify older people with frailty and low HGS.

McArdle disease (muscle glycogen phosphorylase deficiency) is a genetic condition associated with exercise intolerance, but how it affects lean mass (LM) and bone mineral content (BMC) and density (BMD) in patients is unknown. We compared these variables between McArdle patients and age-/sex-matched healthy controls and assessed their potential association with physical activity levels in patients. Methods A case–control, cross-sectional design was used to examine LM, BMC, and BMD by using dual-energy x-ray absorptiometry in 136 young adults of both sexes (36 McArdle patients (33 ± 15 yr) and 103 controls (34 ± 11 yr)). Physical activity was assessed using the International Physical Activity Questionnaire. Results McArdle patients had significantly lower LM values in whole-body and regional sites compared with their corresponding controls, whereas no differences were found (except for the trunk) when physically active patients (n = 23) were compared with controls. All bone-related variables were significantly lower in patients than in controls (average difference of 13% for BMC and 7.6% for BMD). By contrast, no significant differences at the lumbar spine, pelvis, and femur sites were found between physically active patients and controls. Conclusions We report on a previously undescribed condition in McArdle patients, poor bone health, which warrants further attention because it can occur in relatively young adults. An active lifestyle can at least partly alleviate this disorder presumably because of its beneficial effect on LM. Sin financiación 4.478 JCR (2018) Q1, 6/83 Sport Sciences 2.071 SJR (2018) Q1, 12/289 Orthopedics and Sports Medicine, 5/209 Physical Therapy, Sports Therapy and Rehabilitation, 8/125 Sports Science No data IDR 2018 UEM

This study compared the reliability and validity of different protocols evaluating the force-velocity (F-V) relationship and muscle power in older adults. Thirty-one older men and women (75.8±4.7 years) underwent two F-V tests by collecting the mean and peak force and velocity data exerted against increasing loads until one repetition maximum (1RM) was achieved in the leg press exercise. Two attempts per load were performed, with a third attempt when F-V points deviated from the linear F-V regression equation. Then, the subjects performed 2×3 repetitions at 60% 1RM to compare purely concentric and eccentric-concentric repetitions. The Short Physical Performance Battery was conducted to assess the validity of the different protocols. Significant differences were found in maximal power (Pmax) between mean and peak values and between protocols differing in the number of attempts per load (p3), was significantly more reliable (Pmax: CV=2.6%; ICC=0.99) than the other alternatives. Mean values were also observed to be more associated with physical function than peak values (R2=0.34 and 0.15, respectively; p

Purpose: This study aims to analyze the effects of a 3-month vigorous physical activity (VPA) intervention on eating behavior and body composition in overweight and obese children and adolescents. Methods: Forty-seven participants (7–16 years) took part in the study: 28 were assigned to the intervention group (IG) (10 boys and 18 girls) and 19 in a control group (CG) (8 boys and 11 girls). Body composition (dual-energy X-ray absorptiometry), anthropometrics (body mass, height, and body mass index (BMI)), and eating behavior traits (Three-Factor Eating Questionnaire-R21C) were determined before and after the VPA intervention. Results: A decrease in the percentage of body fat and BMI (−2.8% and −1.8%, respectively), and an increase in most lean mass variables were found in the IG (all p ≤ 0.05). In relation to the eating behavior traits, IG subjects showed a 14% reduction in the Emotional Eating score (p = 0.04), while Cognitive Restraint score did not change after the VPA intervention. The baseline factors of the questionnaire predicted changes in body mass and fat mass variables only in the CG. Conclusion: A 3-month VPA intervention influenced eating behaviors of overweight or obese young, especially the Emotional Eating factor, in the presence of favorable body composition changes. Keywords: Appetite, Children, Exercise, Obesity, TFEQ-R21, Young

Introduction and purpose To examine the effect of cardiorespiratory fitness (CRF) and muscle power output (MPO) on bone mass of prepubertal and pubertal children using lean mass (LM) and percentage of fat mass (%FM) as mediator variables. The hypothesis was that both LM and %FM would be independent mediators of the relationships during the sexual maturation period. Methods We analyzed 200 children (88 boys and 112 girls [11.5 ± 2.0 yr]). Body composition was analyzed by bone densitometry, and indirect calorimetry and cycle ergometer were used to calculate V˙O2peak (mL·kg·min) and MPO (W) during an incremental exercise test. Sample was divided by pubertal status. Results In the prepubertal group, LM and %FM acted independently as mediators in the relationship between bone mass and CRF or MPO (22%-25% for LM and 37%-50% for %FM, respectively). In pubertal children, LM acted as mediator at 37%. Conclusions Although the independent mediator role of LM and %FM in the associations between CRF or MPO and bone mass was present during the prepubertal stage, only LM remain its mediator role in these associations during the postpubertal period. Therefore, with growth and sexual maturation, the full effect of LM seems to increase, whereas the influence of %FM seems to disappear.

The objectives were to clarify whether the relationship between physical performance and frailty was independently and jointly mediated by movement behaviors and body composition. We analyzed 871 older adults (476 women) from The Toledo Study for Healthy Aging. Skeletal muscle index (SMI) and fat index (FI) were determined using bone densitometry. Sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) were assessed using accelerometry. The Frailty Trait Scale and The Short Physical Performance Battery (SPPB) were used to evaluate frailty and physical performance, respectively. Simple and multiple mediation analyses were carried out to determine the role of movement behaviors and body composition, adjusted for potential confounders. ST and MVPA acted independently as mediators in the relationship between SPPB and frailty (0.06% for ST and 16.89% for MVPA). FI also acted as an independent mediator in the same relationship (36.47%), while the mediation role of SMI was not significant. MVPA and FI both acted jointly as mediators in this previous relationship explaining 58.15% of the model. Our data support the fact that interventions should simultaneously encourage the promotion of MVPA and strategies to decrease the FI in order to prevent or treat frailty through physical performance improvement.

The assessment and treatment of low relative muscle power in older people has received little attention in the clinical setting when compared to sarcopenia. Our main goal was to assess the associations of low relative power and sarcopenia with other negative outcomes in older people. Methods: The participants were 1189 subjects (54% women; 65–101 years old) from the Toledo Study for Healthy Aging. Probable sarcopenia was defined as having low handgrip strength, while confirmed sarcopenia also included low appendicular skeletal muscle index (assessed by dual energy X-ray absorptiometry) (EWGSOP2’s definition). Low relative (i.e. normalized to body mass) muscle power was assessed with the 5-repetition sit-tostand power test (which uses an equation that converts sit-to-stand performance into mechanical power) and diagnosed in those subjects in the lowest sex-specific tertile. Low usual gait speed (UGS), frailty (according to Fried’s criteria and the Frailty Trait Scale), limitations in basic (BADL) and instrumental activities of daily living (IADL) and poor quality of life were also recorded. Results: Age-adjusted logistic regression analyses demonstrated that low relative muscle power was associated with low UGS (odds ratio (OR) = 1.9 and 2.5), frailty (OR = 3.9 and 4.7) and poor quality of life (OR = 1.8 and 1.9) in older men and women, respectively, and with limitations in BADL (OR = 1.6) and IADL (OR = 3.8) in older women (all p < 0.05). Confirmed sarcopenia was only associated with low UGS (OR = 2.5) and frailty (OR = 5.0) in older men, and with limitations in IADL in older women (OR = 4.3) (all p < 0.05). Conclusions: Low relative muscle power had a greater clinical relevance than low handgrip strength and confirmed sarcopenia among older people. An operational definition and algorithm for low relative muscle power case finding in daily clinical practice was presented.

The aim of this study was to determine the relationship between bone mass (BM) and physical activity (PA) and sedentary behavior (SB) according to frailty status and sex using compositional data analysis. We analyzed 871 older people with an adequate nutritional status. Fried criteria were used to classify by frailty status. Time spent in SB, light intensity PA (LPA) and moderate-to-vigorous intensity PA (MVPA) was assessed from accelerometry for 7 days. BM was determined by dual-energy X-ray absorptiometry (DXA). The combined effect of PA and SB was significantly associated with BM in robust men and women (p &le, 0.05). In relation to the other behaviors, SB was negatively associated with BM in robust men while BM was positively associated with SB and negatively with LPA and MVPA in robust women. Moreover, LPA also was positively associated with arm BM (p &le, 0.01). Finally, in pre-frail women, BM was positively associated with MVPA. In our sample, to decrease SB could be a good strategy to improve BM in robust men. In contrast, in pre-frail women, MVPA may be an important factor to consider regarding bone health.

This study aimed i) to assess the assumptions made in the sit-to-stand (STS) muscle power test [body mass accelerated during the ascending phase (90% of total body mass), leg length (50% of total body height) and concentric phase (50% of total STS time)], ii) to compare force plate-derived (FPD) STS power values with those derived from the STS muscle power test; and iii) to analyze the relationships of both measurements with physical function.Fifty community-dwelling older adults (71.3 ± 4.4 years) participated in the present investigation. FPD STS power was calculated as the product of measured force (force platform) and velocity [difference between leg length (DXA scan) and chair height, divided by time (obtained from FPD data and video analysis)], and compared to estimated STS power using the STS muscle power test. Physical function was assessed by the timed-up-and-go (TUG) velocity, habitual gait speed (HGS) and maximal gait speed (MGS). Paired t-tests, Bland-Altman plots and regressions analyses were conducted.Body mass accelerated during the STS phase was 85.1 ± 3.8% (p 0.05; compared to assumed 90%), leg length was 50.7 ± 1.3% of body height (p 0.05; compared to 50%), and measured concentric time was 50.3 ± 4.6% of one STS repetition (p 0.05; compared to assumed 50%). There were no significant differences between FPD and estimated STS power values (mean difference [95% CI] = 6.4 W [-68.5 to 81.6 W]; p = 0.251). Both FPD and estimated relative (i.e. normalized to body mass) STS power were significantly related to each other (r = 0.95 and ICC = 0.95; p 0.05) and to MGS and TUG velocity after adjusting for age and sex (p 0.05).Estimated STS power was not different from FPD STS power and both measures were strongly related to each other and to maximal physical performance.

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation. Apart from the ventilatory limitations, patients with COPD present an impaired exercise capacity that limits their ability to perform the activities of daily living and impacts negatively on their quality of life. Limb muscle dysfunction is a systemic consequence of COPD associated with exercise intolerance, poor quality of life and increased mortality. This COPD-related syndrome is characterized by reduced muscle cross-sectional area, strength and endurance, and is highly prevalent among COPD patients. Thus, pulmonary rehabilitation (PR) is recommended in order to combat the negative consequences of COPD on patients’ exercise capacity and quality of life. Exercise training is regarded as the cornerstone of PR and can be implemented at any stage of the disease. To date, the combination of resistance and endurance training (i.e. concurrent training) has demonstrated to be the most beneficial exercise intervention in COPD. Concurrent training provides clinically and statistically significant benefits in exercise tolerance and quality of life to patients with COPD. In addition, there are other potential adjuncts to exercise training and strategies to enhance the implementation of PR programs in COPD patients., La enfermedad pulmonar obstructiva crónica (EPOC) se caracteriza por la persistencia de síntomas respiratorios y limitación al flujo de aire. Además de las limitaciones ventilatorias, los pacientes con EPOC presentan una reducida capacidad para realizar ejercicio que limita su habilidad para realizar actividades de la vida diaria e impacta negativamente sobre su calidad de vida. La disfunción muscular de las extremidades es un síntoma sistémico consecuencia de la EPOC y está asociada con la intolerancia al ejercicio, la reducción de la calidad de vida y el aumento de la mortalidad. Este síndrome relacionado con la EPOC se caracteriza por la reducción del área de sección transversal del músculo esquelético, la fuerza y la resistencia, y es altamente prevalente entre los pacientes con EPOC. Así, la rehabilitación pulmonar (RP) está recomendada para combatir las consecuencias negativas de la EPOC sobre la capacidad para realizar ejercicio y la calidad de vida de los pacientes. El entrenamiento con ejercicio es considerado una pieza clave de la RP y puede implementarse en cualquier estadio de la enfermedad. Hasta la fecha, la combinación de entrenamiento de resistencia y fuerza (entrenamiento concurrente) ha demostrado ser la intervención con ejercicio más beneficiosa para la EPOC. El entrenamiento concurrente proporciona beneficios clínica y estadísticamente significativos con respecto a la tolerancia al ejercicio y calidad de vida de los pacientes con EPOC. Además, existen otras terapias y estrategias que potencialmente pueden complementar al entrenamiento con ejercicio para la mejora de la implementación de los programas de RP en pacientes con EPOC.