Determining Changes in Muscle Size and Architecture After Exercise Training: One Site Does Not Fit all.

ABSTRACT: Nunes, JP, Blazevich, AJ, Schoenfeld, BJ, Kassiano, W, Costa, BDV, Ribeiro, AS, Nakamura, M, Nosaka, K, and Cyrino, ES. Determining changes in muscle size and architecture after exercise training: One site does not fit all. J Strength Cond Res 38(4): 787-790, 2024-Different methods can be used to assess muscle hypertrophy, but the effects of training on regional changes in muscle size can be detected only using direct muscle measurements such as muscle thickness, cross-sectional area, or volume. Importantly, muscle size increases vary across regions within and between muscles after resistance training programs (i.e., heterogeneous, or nonuniform, muscle hypertrophy). Muscle architectural changes, including fascicle length and pennation angle, after resistance and stretch training programs are also region-specific. In this paper, we show that the literature indicates that a single-site measure of muscle shape does not properly capture the effects achieved after exercise training interventions and that conclusions concerning the magnitude of muscle adaptations can vary substantially depending on the muscle site to be examined. Thus, we propose that measurements of muscle size and architecture should be completed at multiple sites across regions between the agonist muscles within a muscle group and along the length of the muscles to provide an adequate picture of training effects.

Effect of Resistance Exercise Orders on Health Parameters in Trained Older Women: A Randomized Crossover Trial.

PURPOSE: This study aimed to compare the effects of four resistance exercise orders on muscular strength, body composition, functional fitness, cardiovascular risk factors, and mental health parameters in trained older women. METHODS: The intervention lasted 63 wk. Sixty-one physically independent women (>60 yr) after completing a 12-wk resistance training (RT) preconditioning phase were randomized into four different exercise orders groups to perform 12 wk of RT: multijoint to single-joint and upper- to lower-body, single-joint to multijoint and upper- to lower-body, multijoint to single-joint and lower- to upper-body, and single-joint to multijoint and lower- to upper-body. This was followed by a 12-wk detraining period and another 12-wk RT in which exercise orders were crossed over between MJ-SJ and SJ-MJ conditions. Body composition (dual-energy x-ray absorptiometry), muscular strength (one-repetition maximum tests), functional fitness (gait speed, walking agility, 30-s chair stand, and 6-min walk tests), cardiovascular risk factors (glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, C-reactive protein, advanced oxidation protein product, total radical-trapping antioxidant parameter, and nitric oxide), depressive (Geriatric Depression Scale) and anxiety symptoms (Beck Anxiety Inventory), and cognitive performance (Montreal Cognitive Assessment, Trail Making, verbal fluency, and Stroop test) were analyzed. RESULTS: After the final training period, all groups presented significant improvements ( P < 0.05) in almost all analyzed variables (muscular strength, body composition, functional tests, blood biomarkers, and mental health parameters), without significant difference among exercise orders. CONCLUSIONS: Our results suggest that RT exercise orders in which MJ, SJ, upper, or lower-body exercises are performed first have similar effects on health parameters in trained older women.

Differential Responsiveness for Strength Gain Between Limbs After Resistance Training in Older Women: Impact on Interlimb Asymmetry Reduction.

ABSTRACT: Nunes, JP, Marcori, AJ, Ribeiro, AS, Cunha, PM, Kassiano, W, Costa, BDV, Aguiar, AF, Nakamura, M, Mayhew, JL, and Cyrino, ES. Differential responsiveness for strength gain between limbs after resistance training in older women: Impact on interlimb asymmetry reduction. J Strength Cond Res 36(11): 3209-3216, 2022-The present study compared strength responses between preferred (PREF) and nonpreferred (N-PREF) legs in older women. Muscular strength was measured unilaterally using an isokinetic dynamometer and was analyzed for reproducibility scores, acute performance, and responsiveness to a resistance training (RT) program. One hundred eleven women (aged ≥60 years) performed 12 weeks of whole-body RT (3 times a week; 4 lower-body exercises). Reproducibility scores (intraclass correlation coefficient ≥0.920; following test-retests in part of the sample at pretraining; n = 19), average acute performances, and average strength gains (PREF = ∼6.9%; N-PREF = ∼7.2%) were similar between legs (p > 0.05). However, the individual analyses showed that some subjects were considered responders to strength gains in 1 leg, whereas nonresponders in the other. Nonetheless, when considering the responses in all strength tests, most subjects (91%) were considered responder to at least 1 measure. In addition, it was observed that the strength ratio between PREF/N-PREF legs was altered for those who presented some asymmetry at baseline, as the limbs became more symmetrical in all strength measures after the RT. In conclusion, we observed that some older women may have different levels of strength between legs; however, a traditional 12-week RT program with bilateral exercises can reduce such asymmetry by inducing greater strength gains in the weaker leg.

Equating Resistance-Training Volume Between Programs Focused on Muscle Hypertrophy.

Calculating resistance-training volume in programs focused on muscle hypertrophy is an attempt to quantify the external workload carried out, then to estimate the dose of stimulus imposed on targeted muscles. The volume is usually expressed in some variables that directly affected the total training work, such as the number of sets, repetitions, and volume-load. These variables are used to try to quantify the training work easily, for the subsequent organization and prescription of training programs. One of the main uses of measures of volume quantification is seen in studies in which the purpose is to compare the effects of different training protocols on muscle growth in a volume-equated format. However, it seems that not all measures of volume are always appropriate for equating training protocols. In the current paper, it is discussed what training volume is and the potentials and shortcomings of each one of the most common ways to equate it between groups depending on the independent variable to be compared (e.g., weekly frequency, intensity of load, and advanced techniques).

Responsiveness to muscle mass gain following 12 and 24 weeks of resistance training in older women.

BACKGROUND: Many factors may influence the magnitude of individual responses to resistance training (RT). How the manipulation of training volume and frequency affects responsiveness level for muscle mass gain in older women has not been investigated. AIMS: This study had the objective of identifying responders (RP) and non-responders (N-RP) older women for skeletal muscle mass (SMM) gain from a 12-week resistance training (RT) program. Additionally, we analyzed whether the N-RP could gain SMM with an increase in weekly training volume over 12 additional weeks of training. METHODS: Thirty-nine older women (aged ≥ 60 years) completed 24 weeks of a whole-body RT intervention (eight exercises, 2-3×/week, 1-2 sets of 10-15 repetitions). SMM was estimated by DXA, and the responsive cut-off value was set at two times the standard error of measurement. Participants were considered as RP if they exceeded the cut-off value after a 12-week RT phase, while the N-RP were those who failed to reach the SMM cut-off. RESULTS: Of the 22 participants considered to be N-RP, only 3 accumulated SMM gains (P = 0.250) that exceeded the cut-off point for responsiveness following 12 additional weeks of training, while 19 maintained or presented negative SMM changes. Of the 17 participants considered to be RP, all continued to gain SMM after the second 12-week RT phase. No significant correlation was observed between the changes in SMM and any baseline aspect of the participants. CONCLUSIONS: Our results suggest that some older women are RP, while others are N-RP to SMM gains resulting from RT. Furthermore, the non-responsiveness condition was not altered by an increase of training volume and intervention duration while RP participants continue to increase SMM; it appears that RP continue to be RP, and N-RP continue to be N-RP.

Different Foot Positioning During Calf Training to Induce Portion-Specific Gastrocnemius Muscle Hypertrophy.

Nunes, JP, Costa, BDV, Kassiano, W, Kunevaliki, G, Castro-e-Souza, P, Rodacki, ALF, Fortes, LS, and Cyrino, ES. Different foot positioning during calf training to induce portion-specific gastrocnemius muscle hypertrophy. J Strength Cond Res 34(8): 2347-2351, 2020-The aim of this study was to compare the changes in gastrocnemius muscle thickness (MT) between conditions such as which foot was pointed outward (FPO), foot was pointed inward (FPI), or foot was pointed forward (FPF). Twenty-two young men (23 ± 4 years) were selected and performed a whole-body resistance training program 3 times per week for 9 weeks, with differences in the exercise specific for calves. The calf-raise exercise was performed unilaterally, in a pin-loaded seated horizontal leg-press machine, in 3 sets of 20-25 repetitions for training weeks 1-3 and 4 sets for weeks 4-9. Each subject's leg was randomly assigned for 1 of the 3 groups according to the foot position: FPO, FPI, and FPF. Measurements with a B-mode ultrasound were performed to assess changes in MT of medial and lateral gastrocnemius heads. After the training period, there were observed increases in MT of both medial (FPO = 8.4%, FPI = 3.8%, and FPF = 5.8%) and lateral (FPO = 5.5%, FPI = 9.1%, and FPF = 6.4%) gastrocnemius heads, and significant differences for magnitude of the gains were observed between FPO and FPI conditions (p < 0.05). Positioning FPO potentiated the increases in MT of the medial gastrocnemius head, whereas FPI provided greater gains for the lateral gastrocnemius head. Our results suggest that head-specific muscle hypertrophy may be obtained selectively for gastrocnemius after 9 weeks of calf training in young male adults.

The Generality of Strength: Relationship between Different Measures of Muscular Strength in Older Women.

The aims of this study were: (i) to analyze the relationship between the performance of different measures of muscular strength, and (ii) to identify which measurements present a greater relationship with an overall strength score. Sixty older women (aged 69 ± 6 years) were submitted to muscular strength measurements from isotonic, isokinetic, and isometric tests. An overall-strength score was generated with z-scores of the values obtained in all tests. Interquartile intervals were created for each measure and the overall-strength score. Pearson's r (0.463-0.951, p < 0.05) and Cronbach's α (0.500-0.966) suggested that subjects had relatively similar strength performance compared to their peers in the different tests. Greater associations were observed between tests for similar tasks. In addition, strong-magnitude associations were revealed between all the tests and the overall-strength score (r = 0.710-0.806; α = 0.760-0.846). Factor analysis identified that only two principal components may be sufficient to explain the strength of the sample. All strength measures had high loadings (0.716-0.916) on a common factor with 1 component. The associated eigenvalue with 2 components was 6.8 (84% of the variance). The present results support the phenomenon of the generality of strength in older women. Although greater correlations were observed for tests performed at the same joint, movement, or type of muscular action, the eight tests satisfactorily represented a measure of general muscular strength cross-sectionally.

Influence of Competitive-Anxiety on Heart Rate Variability in Swimmers.

The aim of this study was to analyze the relationship between competitive anxiety and heart rate variability (HRV) in swimming athletes. A total of 66 volunteers (41 male and 27 female) who swam the 400-m freestyle in the Brazilian Swimming Championships participated. Thirty minutes before the 400-m freestyle event, the athletes answered the Competitive Anxiety Inventory (CSAI-2R) questionnaire, then underwent anthropometric (body weight, height, and skinfold thickness) and HRV measurements. Then, at a second meeting, held 3 h after the 400-m freestyle event, the athletes returned to the evaluation room for HRV measurement (Polar® RS800cx, Kempele, Finland). Multiple linear regression was used to evaluate the relationship between competitive anxiety and HRV. The multiple linear regression was performed in three blocks (block 1: cognitive anxiety, block 2: somatic anxiety, and block 3: self-confidence), adopting the forward model. The results indicated a significant association between cognitive anxiety (p = 0.001) and HRV. An increased magnitude of the association was observed when somatic anxiety was inserted in the model (p = 0.001). In contrast, self-confidence showed, which was inserted in block 3, no relationship with HRV (p = 0.27). It was concluded that cognitive and somatic anxieties were associated with the HRV of swimmers. Athletes with a high magnitude of cognitive and/or somatic anxiety demonstrated more significant autonomic nervous system disturbance. Practically, psychological interventions are needed to improve anxiety states that are specific to perform well, and to improve HRV.