Manoel E. Lixandrão

Resistance training‐induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage

Skeletal muscle hypertrophy is one of the main outcomes from resistance training (RT), but how it is modulated throughout training is still unknown. We show that changes in myofibrillar protein synthesis (MyoPS) after an initial resistance exercise (RE) bout in the first week of RT (T1) were greater than those seen post‐RE at the third (T2) and tenth week (T3) of RT, with values being similar at T2 and T3. Muscle damage (Z‐band streaming) was the highest during post‐RE recovery at T1, lower at T2 and minimal at T3. When muscle damage was the highest, so was the integrated MyoPS (at T1), but neither were related to hypertrophy; however, integrated MyoPS at T2 and T3 were correlated with hypertrophy. We conclude that muscle hypertrophy is the result of accumulated intermittent increases in MyoPS mainly after a progressive attenuation of muscle damage.

Comparisons Between Low-intensity Resistance Training With Blood Flow Restriction and High-intensity Resistance Training on Quadriceps Muscle Mass and Strength in Elderly

Abstract Vechin, FC, Libardi, CA, Conceição, MS, Damas, FR, Lixandrão, ME, Berton, RPB, Tricoli, VAA, Roschel, HA, Cavaglieri, CR, Chacon-Mikahil, MPT, and Ugrinowitsch, C. Comparisons between low-intensity resistance training with blood flow restriction and high-intensity resistance training on quadriceps muscle mass and strength in elderly. J Strength Cond Res 29(4): 1071–1076, 2015—High-intensity resistance training (HRT) has been recommended to offset age-related loss in muscle strength and mass. However, part of the elderly population is often unable to exercise at high intensities. Alternatively, low-intensity resistance training with blood flow restriction (LRT-BFR) has emerged. The purpose of this study was to compare the effects of LRT-BFR and HRT on quadriceps muscle strength and mass in elderly. Twenty-three elderly individuals, 14 men and 9 women (age, 64.04 ± 3.81 years; weight, 72.55 ± 16.52 kg; height, 163 ± 11 cm), undertook 12 weeks of training. Subjects were ranked according to their pretraining quadriceps cross-sectional area (CSA) values and then randomly allocated into one of the following groups: (a) control group, (b) HRT: 4 × 10 repetitions, 70–80% one repetition maximum (1RM), and (c) LRT-BFR: 4 sets (1 × 30 and 3 × 15 repetitions), 20–30% 1RM. The occlusion pressure was set at 50% of maximum tibial arterial pressure and sustained during the whole training session. Leg press 1RM and quadriceps CSA were evaluated at before and after training. A mixed-model analysis was performed, and the significance level was set at p ⩽ 0.05. Both training regimes were effective in increasing pre- to post-training leg press 1RM (HRT: ∼54%, p < 0.001; LRT-BFR: ∼17%, p = 0.067) and quadriceps CSA (HRT: 7.9%, p < 0.001; LRT-BFR: 6.6%, p < 0.001); however, HRT seems to induce greater strength gains. In summary, LRT-BFR constitutes an important surrogate approach to HRT as an effective training method to induce gains in muscle strength and mass in elderly.

Sixteen weeks of resistance training can decrease the risk of metabolic syndrome in healthy postmenopausal women.

Background The postmenopausal phase has been considered an aggravating factor for developing metabolic syndrome. Notwithstanding, no studies have as yet investigated the effects of resistance training on metabolic syndrome in postmenopausal women. Thus, the purpose of this study was to verify whether resistance training could reduce the risk of metabolic syndrome in postmenopausal women. Methods Twenty postmenopausal women were randomly assigned to a resistance training protocol (n = 10, 53.40 ± 3.95 years, 64.58 ± 9.22 kg) or a control group (n = 10, 53.0 ± 5.7 years, 64.03 ± 5.03 kg). In the resistance training protocol, ten exercises were performed, with 3 × 8−10 maximal repetitions three times per week, and the load was increased every week. Two-way analysis of variance was used to evaluate specific metabolic syndrome Z-score, high density lipoprotein cholesterol, fasting blood glucose, triglycerides, waist circumference, blood pressure, strength, and body composition. The level of statistical significance was set at P < 0.05. Results The main results demonstrated a significant decrease of metabolic syndrome Z-score when the postmenopausal women performed resistance training (P = 0.0162). Moreover, we observed decreases in fasting blood glucose for the resistance training group (P = 0.001), and also significant improvements in lean body mass (P = 0.042, 2.46%), reduction of body fat percentage (P = 0.001, −6.75%) and noticeable increases in muscle strength after resistance training to leg press (P = 0.004, 41.29%) and bench press (P = 0.0001, 27.23%). Conclusion It was concluded that resistance training performed three times a week may reduce the metabolic syndrome Z-score with concomitant decreases in fasting blood glucose, improvements in body composition, and muscle strength in postmenopausal women.

Time Course of Resistance Training-Induced Muscle Hypertrophy in the Elderly.

Abstract Lixandrão, ME, Damas, F, Chacon-Mikahil, MPT, Cavaglieri, CR, Ugrinowitsch, C, Bottaro, M, Vechin, FC, Conceição, MS, Berton, R, and Libardi, CA. Time course of resistance training–induced muscle hypertrophy in the elderly. J Strength Cond Res 30(1): 159–163, 2016—Extended periods of resistance training (RT) induce muscle hypertrophy. Nevertheless, to date, no study has investigated the time window necessary to observe significant changes in muscle cross-sectional area (CSA) in older adults. Therefore, this study investigated the time course of muscle hypertrophy after 10 weeks (20 sessions) of RT in the elderly. Fourteen healthy older subjects were randomly allocated in either the RT (n: 6) or control group (n: 8). The RT was composed of 4 sets × 10 repetitions (70–80% 1 repetition maximum [1RM]) in a leg press machine. The time course of vastus lateralis muscle hypertrophy (CSA) was assessed on a weekly basis by mode-B ultrasonography. Leg press muscle strength was assessed by dynamic 1RM test. Our results demonstrated that the RT group increased leg press 1RM by 42% (p ⩽ 0.05) after 10 weeks of training. Significant increases in vastus lateralis muscle CSA were observed only after 18 sessions of training (9 weeks; p ⩽ 0.05; 7.1%). In conclusion, our training protocol promoted muscle mass accrual in older subjects, and this was only observable after 18 sessions of RT (9 weeks).

Comparison of maximal muscle strength of elbow flexors and knee extensors between younger and older men with the same level of daily activity.

Background Aging promotes neuromuscular loss, significantly reducing muscle strength. The magnitude of loss of strength seems to be different between the limbs, probably because of differences in activities of daily living (ADL). Therefore, the present study compared the muscle strength of the elbow flexors and knee extensors in younger (n = 7, mean age 23.3 ± 1.2 years) and older (n = 5, mean age 61.8 ± 2.6 years) men matched by ADL level. Methods The study participants performed maximal concentric, isometric, and eccentric contractions of the elbow flexors and knee extensors using an isokinetic dynamometer following a crossover study design. Changes in the dependent variables were compared using mixed model analysis (limb versus age). Results The main results demonstrated that concentric, eccentric, and mean contraction torques for knee extensors were significantly (P < 0.05) higher for younger men than for elderly men. On the other hand, no statistically significant difference (P > 0.05) was found in concentric, isometric, eccentric, and mean torques for elbow flexors between younger and older individuals. Conclusion These results show that elbow flexors maintain better strength than knee extensors through aging, even when comparing individuals with similar ADL levels.

Vastus lateralis muscle cross-sectional area ultrasonography validity for image fitting in humans.

Abstract Lixandrão, ME, Ugrinowitsch, C, Bottaro, M, Chacon-Mikahil, MPT, Cavaglieri, CR, Min, LL, de Souza, EO, Laurentino, GC, and Libardi, CA. Vastus lateralis muscle cross-sectional area ultrasonography validity for image fitting in humans. J Strength Cond Res 28(11): 3293–3297, 2014—The present study aimed to determine the concurrent validity of ultrasound (US) measurement of the vastus lateralis muscle (VL) cross-sectional area (CSA) having magnetic resonance imaging (MRI) as the gold standard measurement, in a heterogeneous sample of participants. Thirty-one individuals (52.44 ± 16.37 years; 1.67 ± 0.11 m; 75.25 ± 13.82 kg) volunteered to participate in the study. All the images were performed in the right leg. Image-fitting technique (US) and computerized planimetry technique (US and MRI) were used to determine the VL CSA. The typical error (TE) of measurement was used to determine the concurrent validity of the US measurements. Our results demonstrated good validity of the US compared with the MRI measurements (TE = 0.37 cm2; coefficient of variation = 1.75%). The Bland-Altman plot demonstrated bias of 0.07 ± 0.53 cm2 and limits of agreement of 0.96–1.11 cm2. Based on our TE, bias and limits of agreement, we concluded that the US image-fitting technique is valid to assess the VL CSA in a heterogeneous sample of participants. Thereby, US can be used instead of MRI to assess changes in skeletal muscle morphology.

An inability to distinguish edematous swelling from true hypertrophy still prevents a completely accurate interpretation of the time course of muscle hypertrophy.

the experimental design are important and described in the “Discussion” section of our article (Damas et al. 2015). The explanation the authors provide in the letter is already acknowledged in our manuscript: “Additionally, DeFreitas et al. (2011) speculated that the significant increase in muscle CSA that they found in the first week of RT in untrained individuals was possibly [italics added for emphasis] due to edema and could be falsely attributed to hypertrophy; thus, they considered that the increased CSA was indicative of hypertrophy only at week 3–4 (when it was different from week 1)”. Since DeFreitas et al. did not provide any measurement of edema it is not possible to estimate the degree of edema that was present at the third week of RT, and that was the main reason that we suggested they might have overestimated the degree of increase in muscle CSA. Importantly, the authors report an increase in muscle CSA of 5.95 % at week 3, leading the reader to believe that this was the actual magnitude of muscle hypertrophy. In their letter, on the other hand, they report (perhaps more appropriately and realistically, in our opinion) an increase in muscle CSA of around 2.41 % (under the assumption that an unchanged amount of edema of 3.45 % was present at this time), which was not clearly stated in their manuscript. In addition, the authors include in their original manuscript the minimal detectable statistical difference approach stating “...if an individual has a preto post-training increase in CSA that is less than 3.37 % [and estimate with an incredible degree of precision], then the change was not real. The change in that scenario could be attributed to the measurement error of the instrument. However, an increase in CSA greater than 3.37 % (in total change) should be attributed to the intervention, which is typically resistance training”. It seems then that a large assumption has been made by DeFreitas et al. that edema is a constant fraction of the CSA measurement and their Dear Editor,

Early- and later-phases satellite cell responses and myonuclear content with resistance training in young men

Satellite cells (SC) are associated with skeletal muscle remodelling after muscle damage and/or extensive hypertrophy resulting from resistance training (RT). We recently reported that early increases in muscle protein synthesis (MPS) during RT appear to be directed toward muscle damage repair, but MPS contributes to hypertrophy with progressive muscle damage attenuation. However, modulations in acute-chronic SC content with RT during the initial (1st-wk: high damage), early (3rd-wk: attenuated damage), and later (10th-wk: no damage) stages is not well characterized. Ten young men (27 ± 1 y, 23.6 ± 1.0 kg·m-2) underwent 10-wks of RT and muscle biopsies (vastus-lateralis) were taken before (Pre) and post (48h) the 1st (T1), 5th (T2) and final (T3) RT sessions to evaluate fibre type specific SC content, cross-sectional area (fCSA) and myonuclear number by immunohistochemistry. We observed RT-induced hypertrophy after 10-wks of RT (fCSA increased ~16% in type II, P < 0.04; ~8% in type I [ns]). SC content increased 48h post-exercise at T1 (~69% in type I [P = 0.014]; ~42% in type II [ns]), and this increase was sustained throughout RT (pre T2: ~65%, ~92%; pre T3: ~30% [ns], ~87%, for the increase in type I and II, respectively, vs. pre T1 [P < 0.05]). Increased SC content was not coupled with changes in myonuclear number. SC have a more pronounced role in muscle repair during the initial phase of RT than muscle hypertrophy resulted from 10-wks RT in young men. Chronic elevated SC pool size with RT is important providing proper environment for future stresses or larger fCSA increases.

High-frequency resistance training does not promote greater muscular adaptations compared to low frequencies in young untrained men

Abstract The aim of the study was to compare the effect of resistance training (RT) frequencies of five times (RT5), thrice- (RT3) or twice- (RT2) weekly in muscle strength and hypertrophy in young men. Were used a within-subjects design in which 20 participants had one leg randomly assigned to RT5 and the other to RT3 or to RT2. 1 RM and muscle cross-sectional area (CSA) were assessed at baseline, after four (W4) and eight (W8) RT weeks. RT5 resulted in greater total training volume (TTV) than RT3 and RT2 (P = .001). 1 RM increased similarly between protocols at W4 (RT5: 55 ± 9 Kg, effect size (ES): 1.18; RT3: 51 ± 11 Kg, ES: 0.80; RT2: 54 ± 7 Kg, ES: 1.13; P < .0001) and W8 (RT5: 62 ± 11 Kg, ES: 1.81; RT3: 57 ± 11 Kg, ES: 1.40; RT2: 60 ± 8 Kg, ES: 1.98; P < .0001) vs. baseline (RT5: 45 ± 9 Kg; RT3: 42 ± 11 Kg; RT2: 46 ± 7 Kg). CSA increased similarly between protocols at W4 (RT5: 24.6 ± 3.9 cm2, ES: 0.54; RT3: 22.0 ± 4.6 cm2, ES: 0.19; RT2: ES: 0.25; 23.8 ± 3.8 cm2; P < .001), and W8 (RT5: 25.3 ± 4.3 cm2; ES: 0.69; RT3: 23.6 ± 4.2 cm2, ES: 0.58; RT2: 25.5 ± 3.7 cm2; ES: 0.70; P < .0001) vs. baseline (RT5: 22.5 ± 3.8 cm2; RT3: 21.2 ± 4.0 cm2; RT2: 22.9 ± 3.8 cm2). Performing RT5, RT3 and RT2 a week result in similar muscle strength increase and hypertrophy, despite higher TTV for RT5.

Effects of weightlifting exercise, traditional resistance and plyometric training on countermovement jump performance: a meta-analysis

ABSTRACT Jump performance is considered an important factor in many sports. Thus, strategies such as weightlifting (WL) exercises, traditional resistance training (TRT) and plyometric training (PT) are effective at improving jump performance. However, it is not entirely clear which of these strategies can enable greater improvements on jump height. Thus, the purpose of the meta-analysis was to compare the improvements on countermovement jump (CMJ) performance between training methods which focus on WL exercises, TRT, and PT. Seven studies were included, of which one study performed both comparison. Therefore, four studies comparing WL exercises vs. TRT (total n = 78) and four studies comparing WL exercises vs. PT (total n = 76). The results showed greater improvements on CMJ performance for WL exercises compared to TRT (ESdiff: 0.72 ± 0.23; 95%CI: 0.26, 1.19; P = 0.002; Δ % = 7.5 and 2.1, respectively). The comparison between WL exercises vs. PT revealed no significant difference between protocols (ESdiff: 0.15 ± 0.23; 95%CI: −0.30, 0.60; P = 0.518; Δ % = 8.8 and 8.1, respectively). In conclusion, WL exercises are superior to promote positive changes on CMJ performance compared to TRT; however, WL exercises and PT are equally effective at improving CMJ performance.