Cíntia E. Botton

Low- and high-volume strength training induces similar neuromuscular improvements in muscle quality in elderly women.

The aim of this study was to compare the effects of low- and high-volume strength training on strength, muscle activation and muscle thickness (MT) of the lower- and upper-body, and on muscle quality (MQ) of the lower-body in older women. Twenty apparently healthy elderly women were randomly assigned into two groups: low-volume (LV, n=11) and high-volume (HV, n=9). The LV group performed one-set of each exercise, while the HV group performed three-sets of each exercise, twice weekly for 13 weeks. MQ was measured by echo intensity obtained by ultrasonography (MQEI), strength per unit of muscle mass (MQST), and strength per unit of muscle mass adjusted with an allometric scale (MQAS). Following training, there was a significant increase (p≤0.001) in knee extension 1-RM (31.8±20.5% for LV and 38.3±7.3% for HV) and in elbow flexion 1-RM (25.1±9.5% for LV and 26.6±8.9% for HV) and in isometric maximal strength of the lower-body (p≤0.05) and upper-body (p≤0.001), with no difference between groups. The maximal electromyographic activation for both groups increased significantly (p≤0.05) in the vastus medialis and biceps brachii, with no difference between groups. All MT measurements of the lower- and upper-body increased similarly in both groups (p≤0.001). Similar improvements were also observed in MQEI (p≤0.01), MQST, and MQAS (p≤0.001) for both groups. These results demonstrate that low- and high-volume strength training promote similar increases in neuromuscular adaptations of the lower- and upper-body, and in MQ of the lower-body in elderly women.

EFFECT OF RANGE OF MOTION ON MUSCLE STRENGTH AND THICKNESS

Abstract Pinto, RS, Gomes, N, Radaelli, R, Botton, CE, Brown, LE, and Bottaro, M. Effect of range of motion on muscle strength and thickness. J Strength Cond Res 26(8): 2140–2145, 2012—The purpose of this investigation was to compare partial range-of-motion vs. full range-of-motion upper-body resistance training on strength and muscle thickness (MT) in young men. Volunteers were randomly assigned to 3 groups: (a) full range of motion (FULL; n = 15), (b) partial range of motion (PART; n = 15), or (c) control (CON; n = 10). The subjects trained 2 d·wk−1 for 10 weeks in a periodized program. Primary outcome measures included elbow flexion maximal strength measured by 1 repetition maximum (1RM) and elbow flexors MT measured by ultrasound. The results indicated that elbow flexion 1RM significantly increased (p < 0.05) for the FULL (25.7 ± 9.6%) and PART groups (16.0 ± 6.7%) but not for the CON group (1.7 ± 5.5%). Also, FULL 1RM strength was significantly greater than the PART 1RM after the training period. Average elbow flexor MT significantly increased for both training groups (9.65 ± 4.4% for FULL and 7.83 ± 4.9 for PART). These data suggest that muscle strength and MT can be improved with both FULL and PART resistance training, but FULL may lead to greater strength gains.

Concurrent strength and endurance training exercise sequence does not affect neuromuscular adaptations in older men

Concurrent training is an effective method for increasing skeletal muscle performance in aging individuals, but controversy exists as to whether chronic neuromuscular and functional adaptations are affected by the intra-session exercise sequence. Therefore the aim of this study was to evaluate the effect of concurrent endurance and power-like strength training exercise sequence on muscular and functional adaptations of older participants. Thirty-six healthy older men not engaged in systematic exercise training programs for at least 6 months were divided into a control group (CON; 65.8±5.3 years), or in the training groups: endurance-strength (ES; 63.2±3.3 years), or strength-endurance (SE; 67.1±6.1 years). Training groups underwent 12 weeks of concurrent endurance and power-like strength training, starting every exercise session with either endurance (in ES) or strength (in SE) exercises. Measurements included knee extension one repetition maximum (1RM), knee extension power, 30 second sit-to-stand test (30SS), maximum vastus lateralis surface electromyographic activity, and rectus femoris echo intensity (RFEI). Significant increases in maximal strength (ES +18±11.3%; SE +14.2±6.0%; p≤0.05), peak power (ES +22.2±19.4%; SE +26.3±31.3%; p≤0.05), and 30SS performance (ES +15.2±7.2%; SE +13.2±11.8%; p≤0.05) were observed only in the training groups, with no differences between ES and SE. Maximum muscular activity was greater after 12weeks at training groups (p≤0.05), and reductions in RFEI were found only in ES and SE (p≤0.05). These results demonstrate that concurrent strength and endurance training performed twice a week effectively increases muscular performance and functional capacity in older men, independent of the intra-session exercise sequence. Additionally, the RFEI decreases indicate an additional adaptation to concurrent training.

Neuromuscular Adaptations to Unilateral vs. Bilateral Strength Training in Women.

Abstract Botton, CE, Radaelli, R, Wilhelm, EN, Rech, A, Brown, LE, and Pinto, RS. Neuromuscular adaptations to unilateral vs. bilateral strength training in women. J Strength Cond Res 30(7): 1924–1932, 2016—Considering the bilateral deficit, the sum of forces produced by each limb in a unilateral condition is generally greater than that produced by them in a bilateral condition. Therefore, it can be speculated that performing unilateral strength exercises may allow greater training workloads and subsequently greater neuromuscular adaptations when compared with bilateral training. Hence, the purpose of this study was to compare neuromuscular adaptations with unilateral vs. bilateral training in the knee extensor muscles. Forty-three recreationally active young women were allocated to a control, unilateral (UG) or bilateral (BG) training group, which performed 2 times strength training sessions a week for 12 weeks. Knee extension one repetition maximum (1RM), maximal isometric strength, muscle electrical activity, and muscle thickness were obtained before and after the study period. Muscle strength was measured in unilateral (right + left) and bilateral tests. Both UG and BG increased similarly their unilateral 1RM (33.3 ± 14.3% vs. 24.6 ± 11.9%, respectively), bilateral 1RM (20.3 ± 6.8% vs. 28.5 ± 12.3%, respectively), and isometric strength (14.7 ± 11.3% vs. 13.1 ± 12.5%, respectively). The UG demonstrated greater unilateral isometric strength increase than the BG (21.4 ± 10.5% vs. 10.3 ± 11.1%, respectively) and only the UG increased muscle electrical activity. Muscle thickness increased similarly for both training groups. Neither group exhibited pretesting 1RM bilateral deficit values, but at post-testing, UG showed a significant bilateral deficit (−6.5 ± 7.8%) whereas BG showed a significant bilateral facilitation (5.9 ± 9.0%). Thus, performing unilateral or bilateral exercises was not a decisive factor for improving morphological adaptations and bilateral muscle strength in untrained women. Unilateral training, however, potentiate unilateral specific strength gains.

Bilateral deficit between concentric and isometric muscle actions

The greater torque generation capacity of muscles when contracted alone than in combination with contralateral muscles, characterizes the bilateral limb deficit (BLD) phenomenon. Few studies have explored the BLD in dynamic movements, because isometric actions are considered ideal for evaluating strength. Therefore, the aim of this study was to compare BLD between isometric and concentric actions of the knee extensors. Eleven healthy young men (age = 20.6 ± 1 yrs; weight = 71.4 ± 6.4 kg; height = 174.4 ± 7 cm) volunteered to participate. Initially, subjects visited the laboratory for familiarization with the test protocols. On two subsequent randomized days they performed a test protocol with either a unilateral (right and left limbs) or bilateral condition, with 48 h rest between. The test protocol was composed of five isokinetic concentric actions of the knee extensors at 60 ◦ /s and three isometric actions at a 60 ◦ angle of knee flexion. The greatest peak torque of the two conditions was used for analyses. Both muscle actions demonstrated greater values unilaterally ( p 0.05). Therefore, if muscle torque production is greater unilaterally, athletes and coaches may utilize unilateral exercises to increase training loads.

Single-joint isometric rate of torque development is not related to counter- movement jump performance in soccer players

BACKGROUND AND OBJECTIVE: The quadriceps rate of torque development (RTD) is frequently used to evaluate explosive performance, but its functional meaning has been questioned. Thus, the aim of this study was to investigate if isometric quadriceps RTD correlates with multi-joint dynamic performance and if it has greater correlation with dynamic performance than with a single-joint isokinetic test in soccer players. METHODS: Thirty-nine male soccer players (age 21 ± 5 years, body mass 75 ± 7.5 kg, height 179 ± 5 cm) performed five maximal concentric knee extension isokinetic contractions at a velocity of 180 ◦ /s, followed by three maximal voluntary isometric contractions (MVIC) with knee angle of 60 ◦ , and five countermovement jumps (CMJ). The RTD was derived from MIVC over various time intervals (of 0.05, 0.1, 0.2, 0.3 seconds, and peak RTD) and CMJ height was calculated by flight time method. Pearson Product Moment Correlations were used to determine the relationships between variables. RESULTS: Absolute and relative isokinetic PT correlated positively with CMJ height ( p 0.05, r from �0.272 to 0.296). CONCLUSION:These results indicate that single-joint isometric RTDdoes not correlate withdynamic multi-joint performance. Thus, more specific tests in relation to contraction type, velocity and/or movement pattern should be used.

The effects of flexibility training on exercise-induced muscle damage in young men with limited hamstrings flexibility

Adaptations to 6 weeks of supervised hamstring stretching training and its potential impact on symptoms of eccentric exercise‐induced muscle damage (EIMD) were studied in 10 young, untrained men with limited hamstrings flexibility. Participants performed unilateral flexibility training (experimental leg; EL) on an isokinetic dynamometer, while the contralateral limb acted as control (CL). Hip range of motion (ROM), passive, isometric, and concentric torques, active optimum angle, and biceps femoris and semitendinosus muscle thickness and ultrasound echo intensity were assessed both before and after the training. Additionally, muscle soreness was assessed before and after an acute eccentric exercise bout in both legs (EL and CL) at post‐training only. Hip ROM increased (P < .001) only in EL after the training (EL = 10.6° vs CL = 1.6°), but no changes (P > .05) in other criterion measurements were observed. After a bout of eccentric exercise at the end of the program, isometric and dynamic peak torques and muscle soreness ratings were significantly altered at all time points equally in EL and CL. Also, active optimum angle was reduced immediately, 48 and 72 hours post‐exercise, and hip ROM was reduced at 48 and 72 hours equally in EL and CL. Finally, biceps femoris muscle thickness was significantly increased at all time points, and semitendinosus thickness and echo intensity significantly increased at 72 hours, with no significant differences between legs. The stretching training protocol significantly increased hip ROM; however, it did not induce a protective effect on EIMD in men with tight hamstrings.

Effects of resistance training on neuromuscular parameters in elderly with type 2 diabetes mellitus: A randomized clinical trial

&NA; This study is a randomized controlled clinical trial that verified the resistance training efficacy on neuromuscular parameters, with muscle quality as primary outcome. Forty‐four elderly with diabetes type 2 (69.7 ± 6.9 years; 26 men) were randomly allocated to a 12‐weeks resistance training group (RTG, 3 times a week), or an active control group with stretching classes (CG, once a week). Primary and secondary outcomes were assessed at baseline and after 12 weeks, as follow: quadriceps muscle thickness and rectus femoris muscle quality, maximal knee extension strength, rapid strength, functional performance, visceral adipose tissue, glycemic control, lipid profile and quality of life. Generalized estimating equations were used to analyses based on intention‐to‐treat and per‐protocol approaches, which showed the same results. Among all outcomes measured there were improvements in the knee extension strength (P < 0.001) and quadriceps muscle thickness (P < 0.001) for RTG. The muscle quality did not improve for both groups (P = 0.98). For the secondary outcomes there were no improvements for functional performance, rapid strength, glycemic control, quality of life, visceral adipose tissue and lipid profile in both groups, with exception of triglyceride level reduction for RTG (P = 0.04).The resistance training program is an efficacious strategy for improve the neuromuscular health in elderly with T2DM, considering increases in lower limb strength and muscle mass, but the same was not found for muscle quality, rapid strength, functional performance and quality of life. Furthermore, the training program did not induce significant reduction in glycated hemoglobin values of patients who already had suitable glycemic control.