Does static stretching change uniformly the quadriceps elasticity in physically actives subjects?

PURPOSE: Verify the acute responses of static stretching (SS) on the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) elasticity and knee/hip range of motion (ROM). Additionally, to investigate if there are consistency among quadriceps muscle elasticity after SS. METHODS: Acute effect of SS on pre-post-intervention design. Thirtheen healthy participants (both genders) proposed for a pre-post experimental design. RF, VM, and VL elasticity (strain ratio, SR) was evaluated bilaterally by ultrasound with quasi-static elastography. Higher SR values refer to more rigid tissues. A SS protocol of 3 series of 30 s was applied at right lower limb. The left lower limb was considered as control group. Also, photogrammetry evaluated the knee/hip ROM. RESULTS: For SR muscle comparisons, VM was lower (less stiff) than VL and RF at pre- and post-SS. For time comparisons, no differences were observed for SR and ROM at pre- and post-SS. However, the effect size of the quadriceps SR at SS lower limb was higher than control. CONCLUSION: Acute effects of SS did not change the quadriceps SR or knee/hip ROM in healthy and active subjects. Non-uniform quadriceps SR are observed (VM < VL and RF) independently of SS. Future studies should consider different protocols, muscles, and populations.

Influence of subcutaneous adipose thickness and dominance on reliability of quadriceps muscle quality in healthy young individuals.

BACKGROUND: Echo intensity (EI) can be useful to check muscle quality and has been widely used to identify tissue damage. In the clinical and sports context, it has been used to identify metabolic disorders and training muscle performance. OBJECTIVE: To determine whether subcutaneous adipose thickness (SAT) influences the inter-session EI reliability of the quadriceps femoris and whether EI is influenced by dominance in young healthy subjects. DESIGN: All procedures were approved by the local Institutional Research Ethics Committee (project number 2.620.204). This is a cross-sectional study where 19 healthy young individuals volunteered. METHOD: The individuals were assessed at two time points by an experienced examiner. Imaging of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles were performed bilaterally by ultrasonography. EI and SAT analysis was performed using ImageJ®software. RESULTS/FINDINGS: Inter-session intraclass correlation coefficient (ICC) for EImeasured showed moderate reliability for RF (R = 0.578; P = 0.038) and VL (R = 0.735; P = 0.004) and low for VM (R = 0.402; P = 0.142). When corrected by SAT, inter-session (EIcorrected), ICC values showed good reliability for RF (R = 0.826; P < 0.001) and VM (R = 0.765; P = 0.002) and excellent for VL (R = 0.909; P < 0.001). Considering inter-side reliability, Student's paired t-test demonstrated no difference for EImeasured (P > 0.283), EIcorrected (P > 0.127), and SAT (P > 0.356). CONCLUSIONS: SAT influenced the inter-session reliability values of EI in all muscles evaluated. Although they showed similarity, EI values were not influenced by dominance in young healthy subjects.

Mixed Session Periodization as a New Approach for Strength, Power, Functional Performance, and Body Composition Enhancement in Aging Adults.

Berzerra, ES, Orssatto, LBR, Moura, BM, Willardson, JM, Simão, R, and Moro, ARP. Mixed session periodization as a new approach for strength, power, functional performance, and body composition enhancement in aging adults. J Strength Cond Res 32(10): 2795-2806, 2018-The purpose of this study was to compare the effects of mixed session periodization (MSP) vs. traditional periodization (TP) on strength, power, functional performance, and body composition in aging adults. Forty-five healthy aging adults were randomly divided into 3 groups: MSP, TP, and Control. Subjects were tested before the intervention for baseline values (week 4) and then repeated testing during (week 7 and week 11), as well as after the intervention (week 15). Subjects were tested on the following performance measures: 5 repetition maximum (5RM) leg press and seated leg curl; 12RM cable chest press; countermovement jump (CMJ) and squat jump; up-and-down stairs; timed up and go (TUG); and body composition. All comparisons were analyzed through a mixed-model analysis with repeated measures (group × time) and with Bonferroni post hoc tests (p ≤ 0.05). After the intervention, no significant differences were observed between experimental groups; however, the MSP and TP groups demonstrated significantly greater values vs. the Control group in the 5RM leg press (p < 0.01), seated leg curl (p < 0.01), and 12RM cable chest press (p < 0.001). For CMJ performance, the MSP and TP groups significantly increased at week 7 (p < 0.001). The MSP and TP groups significantly improved functional task performance, including TUG (p < 0.001), upstairs (p < 0.01), and downstairs (p < 0.01) after training. Furthermore, body composition for the lower limbs significantly changed for the MSP and TP groups, with increased fat-free mass (p < 0.001) and decreased fat mass (p < 0.01) after training. In conclusion, the MSP and TP models used in this study were equally effective in developing strength, power, and functional performance while increasing fat-free mass and improving body fat percentage in aging adults. However, it should be considered that the MSP protocol did result in greater effect sizes in lower-limb strength, lower-limb fat-free mass, up-and-down stair, and TUG performance.

Anthropometric profile of military firefighters: comparison between operational and administrative work groups.

BACKGROUND: Body composition is relevant for the health and work performance of firefighters. However, the behavior of these parameters has not been elucidated for groups of firefighters performing different tasks. OBJECTIVES: To compare the anthropometric profile of military firefighters who perform administrative (ADM) or operational work . METHODS: The sample comprised 121 (ADM = 50 and operational = 71) male military firefighters. Body mass (BM), body fat percentage (BFP), fat body mass, lean body mass, body mass index (BMI), waist circumference and somatotype were analyzed. RESULTS: Intergroup difference was found for body mass (ADM = 78.5 kg - operational = 84.6 kg), BMI (ADM = 25.8 - operational = 27.2) and lean body mass (ADM = 61.9 kg - operational = 66.2 kg). CONCLUSION: The groups exhibited differences in their anthropometric profile and BFP and BMI above the recommended range.

INTRODUÇÃO: A composição corporal é importante para o bombeiro militar no que diz respeito a sua saúde e ao seu desempenho no trabalho. Porém, o comportamento desse parâmetro não é elucidado nos diferentes grupos de trabalho do bombeiro militar. OBJETIVO: Comparar o perfil antropométrico de bombeiros militares entre os grupos de trabalho administrativo (ADM) e operacional. MÉTODOS: A amostra foi composta por 121 (ADM = 50 e operacional = 71) bombeiros militares do sexo masculino. Foram aferidos massa corporal (MC), percentual de gordura (%G), massa gorda, massa magra, índice de massa corporal (IMC), circunferência da cintura (CC) e somatotipia. RESULTADOS: Houve diferenças entre os grupos para as variáveis massa corporal (ADM = 78,5 kg - operacional = 84,6 kg), IMC (ADM = 25,8 - operacional = 27,2) e massa magra (ADM = 61,9 kg - operacional = 66,2 kg). CONCLUSÃO: Conclui-se que os grupos apresentam diferenças entre os perfis antropométricos e apresentam %G e IMC acima do recomendável.

Effects of mate tea consumption on muscle strength and oxidative stress markers after eccentric exercise.

Dietary phytochemical supplementation may improve muscle recovery from exercise. In this study, we investigated the effect of mate tea (MT) consumption - a phenol-rich beverage - on muscle strength and oxidative stress biomarkers after eccentric exercise. In a randomised, cross-over design, twelve men were assigned to drink either MT or water (control; CON) for 11 d. On the 8th day, subjects performed three sets of twenty maximal eccentric elbow flexion exercises. Maximal isometric elbow flexion force was measured before and at 0, 24, 48 and 72 h after exercise. Blood samples were obtained before and at 24, 48 and 72 h after exercise and analysed for total phenolics, GSH, GSSG, GSH:GSSG ratio and lipid hydroperoxides (LOOH). After eccentric exercise, muscle strength was significantly reduced over time, regardless of treatments. However, MT improved the rate of strength recovery by 8·6 % on the 1st day after exercise (P<0·05). Plasma concentration of total phenolic compounds was higher in MT than in CON at all time points (P<0·05) but decreased significantly at 72 h after exercise in both trials (P<0·05). Blood levels of GSH were significantly decreased at 48 and 72 h after exercise in CON (P<0·05) but did not change over time in MT. No significant changes were observed for GSSG, GSH:GSSG ratio and LOOH levels. MT intake did not influence muscle strength at all time points assessed but hastened the strength recovery over 24 h after exercise. MT also favoured the concentration of blood antioxidant compounds.