Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 145
Filtrar
1.
J Strength Cond Res ; 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32058362

RESUMO

Aube, D, Wadhi, T, Rauch, J, Anand, A, Barakat, C, Pearson, J, Bradshaw, J, Zazzo, S, Ugrinowitsch, C, and De Souza, EO. Progressive resistance training volume: effects on muscle thickness, mass, and strength adaptations in resistance-trained individuals. J Strength Cond Res XX(X): 000-000, 2020-This study investigated the effects of 12-SET, 18-SET, and 24-SET lower-body weekly sets on muscle strength and mass accretion. Thirty-five resistance-trained individuals (one repetition maximum [1RM] squat: body mass ratio [1RM: BM] = 2.09) were randomly divided into 12-SET: n = 13, 18-SET: n = 12, and 24-SET: n = 10. Subjects underwent an 8-week resistance-training (RT) program consisting of 2 weekly sessions. Muscle strength (1RM), repetitions to failure (RTF) at 70% of 1RM, anterior thigh muscle thickness (MT), at the medial MT (MMT) and distal MT (DMT) points, as well as the sum of both sites (ΣMT), along with region of interest for fat-free mass (ROI-FFM) were measured at baseline and post-testing. For the 1RM, there was a main time effect (p ≤ 0.0001). However, there was a strong trend toward significance (p = 0.052) for group-by-time interaction, suggesting that 18-SET increased 1RM back squat to a greater extent compared with 24-SET, (24-SET: 9.5 kg, 5.4%; 18-SET: 25.5 kg, 16.2%; 12-SET: 18.3 kg, 11.3%). For RTF, only a main time-effect (p ≤ 0.0003) was observed (24-set: 5.7 reps, 33.1%; 18-SET: 2.4 reps, 14.5%; 12-SET: 5.0 reps, 34.8%). For the MMT, DMT, ΣMT, and ROI-FFM, there was only main time-effect (p ≤ 0.0001), (MMT: 24-SET: 0.15 cm, 2.7%; 18-SET: 0.32 cm, 5.7%; 12-SET: 0.38 cm, 6.4%-DMT: 24-set: 0.39 cm, 13.1%; 18-SET: 0.28 cm, 8.9%; 12-SET: 0.34 cm, 9.7%-ΣMT: 24-set: 0.54 cm, 6.1%; 18-SET: 0.60 cm, 6.7%; 12-SET: 0.72 cm, 7.7%, and ROI-FFM: 24-set: 0.70 kg, 2.6%; 18-SET: 1.09 kg, 4.2%; 12-SET: 1.20 kg, 4.6%, respectively). Although all of the groups increased maximum strength, our results suggest that the middle dose range may optimize the gains in back squat 1RM. Our findings also support that differences in weekly set number did not impact in MT and ROI-FFM adaptations in subjects who can squat more than twice their body mass.

2.
J Strength Cond Res ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32108724

RESUMO

Scarpelli, MC, Nóbrega, SR, Santanielo, N, Alvarez, IF, Otoboni, GB, Ugrinowitsch, C, and Libardi, CA. Muscle hypertrophy response is affected by previous resistance training volume in trained individuals. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to compare gains in muscle mass of trained individuals after a resistance training (RT) protocol with standardized (i.e., nonindividualized) volume (N-IND), with an RT protocol using individualized volume (IND). In a within-subject approach, 16 subjects had one leg randomly assigned to N-IND (22 sets·wk, based on the number of weekly sets prescribed in studies) and IND (1.2 × sets·wk recorded in training logs) protocols. Muscle cross-sectional area (CSA) was assessed by ultrasound imaging at baseline (Pre) and after 8 weeks (Post) of RT, and the significance level was set at p < 0.05. Changes in the vastus lateralis CSA (difference from Pre to Post) were significantly higher for the IND protocol (p = 0.042; mean difference: 1.08 cm; confidence interval [CI]: 0.04-2.11). The inferential analysis was confirmed by the CI of the effect size (0.75; CI: 0.03-1.47). Also, the IND protocol had a higher proportion of individuals with greater muscle hypertrophy than the typical error of the measurement (chi-square, p = 0.0035; estimated difference = 0.5, CI: 0.212-0.787). In conclusion, individualizing the weekly training volume of research protocols provides greater gains in muscle CSA than prescribing a group standard RT volume.

3.
J Physiol ; 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32020612

RESUMO

KEY POINTS: Individuals with freezing of gait (FoG) due to Parkinson's disease (PD) have small and long anticipatory postural adjustments (APAs) associated with delayed step initiation. Individuals with FoG ('freezers') may require functional reorganization of spinal mechanisms to perform APAs due to supraspinal dysfunction. As presynaptic inhibition (PSI) is centrally modulated to allow execution of supraspinal motor commands, it may be deficient in freezers during APAs. We show that freezers presented PSI in quiet stance (control task), but they presented loss of PSI (i.e. higher ratio of the conditioned H-reflex relative to the test H-reflex) during APAs before step initiation (functional task), whereas non-freezers and healthy control individuals presented PSI in both the tasks. The loss of PSI in freezers was associated with both small APA amplitudes and FoG severity. We hypothesize that loss of PSI during APAs for step initiation in freezers may be due to FoG. ABSTRACT: Freezing of gait (FoG) in Parkinson's disease involves deficient anticipatory postural adjustments (APAs), resulting in a cessation of step initiation due to supraspinal dysfunction. Individuals with FoG ('freezers') may require functional reorganization of spinal mechanisms to perform APAs. As presynaptic inhibition (PSI) is centrally modulated to allow execution of supraspinal motor commands, here we hypothesized a loss of PSI in freezers during APA for step initiation, which would be associated with FoG severity. Seventy individuals [27 freezers, 22 non-freezers, and 21 age-matched healthy controls (HC)] performed a 'GO'-commanded step initiation task on a force platform under three conditions: (1) without electrical stimulation, (2) test Hoffman reflex (H-reflex) and (3) conditioned H-reflex. They also performed a control task (quiet stance). In the step initiation task, the H-reflexes were evoked on the soleus muscle when the amplitude of the APA exceeded 10-20% of the mean baseline mediolateral force. PSI was quantified by the ratio of the conditioned H-reflex relative to the test H-reflex in both the tasks. Objective assessment of FoG severity (FoG-ratio) was performed. Freezers presented lower PSI levels during quiet stance than non-freezers and HC (P < 0.05). During step initiation, freezers presented loss of PSI and lower APA amplitudes than non-freezers and HC (P < 0.05). Significant correlations were only found for freezers between loss of PSI and FoG-ratio (r = 0.59, P = 0.0005) and loss of PSI and APA amplitude (r = -0.35, P < 0.036). Our findings suggest that loss of PSI for step initiation in freezers may be due to FoG.

4.
Med Sci Sports Exerc ; 52(2): 507-514, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31469710

RESUMO

PURPOSE: Sleep is considered essential for muscle recovery, mainly due to its effect on hormone secretion. Total sleep deprivation or restriction is known to alter not only blood hormones but also cytokines that might be related to skeletal muscle recovery. This study aimed to evaluate whether total sleep deprivation after eccentric exercise-induced muscle damage (EEIMD) modifies the profiles of blood hormones and cytokines. METHODS: In two separate conditions, with a crossover and randomized model, 10 men (age, 24.5 ± 2.9 yr; body mass index, 22.7 ± 2.3 kg·m) performed a unilateral EEIMD protocol that comprised 240 eccentric contractions of the knee extensor muscles using an isokinetic dynamometer. In one condition, a "muscle damage" protocol was followed by 48 h of total sleep deprivation and 12 h of normal sleep (DEPRIVATION). In the other condition, the same muscle damage protocol was conducted, followed by three nights of regular sleep (SLEEP). Isometric muscle voluntary contraction tests and blood samples were collected serially throughout the protocol and analyzed for creatine kinase, free and total testosterone, IGF-1, cortisol, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, receptor antagonist of IL-1 and IL-10. RESULTS: Muscle voluntary contraction and serum creatine kinase increased equally over the study period in both conditions. From the cytokines evaluated, only IL-6 increased in DEPRIVATION. No differences were detected in testosterone levels between conditions, but IGF-1, cortisol, and cortisol/total testosterone ratio were higher in DEPRIVATION. CONCLUSIONS: Total sleep deprivation after EEIMD does not delay muscle strength recovery but modifies inflammatory and hormonal responses.

5.
PM R ; 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31278834

RESUMO

BACKGROUND: Minimal detectable change (MDC) when assessing balance using the Biodex Balance System (BBS) in patients with Parkinson disease (PD) is currently unknown, limiting the interpretability of the scores. OBJECTIVE: To determine the MDC on the Anterior/Posterior Stability Index (APSI), Medial/Lateral Stability Index (MLSI), and Overall Stability Index (OSI) from postural stability and fall risk protocols of the BBS in patients with PD. DESIGN: This was a repeated-measures design (at a 1-week interval). SETTING: Strength training laboratory of a public university. PATIENTS: 46 patients with PD (men and women) at stages 2 and 3 (67.9 ± 7.4 years old) were assessed in the "on" state (fully medicated). METHODS: Patients performed three trials of 20 s for each protocol. MAIN OUTCOME MEASUREMENTS: Absolute and relative MDC (MDC%) calculated for APSI, MLSI, and OSI from the postural stability (stable condition) and fall risk protocols (unstable condition). RESULTS: For the postural stability, the MDC and MDC% were 0.26° and 17% for APSI, 0.41° and 21% for MLSI, and 0.22° and 12% for OSI, respectively. For the fall risk, the MDC and MDC% were 0.51° and 18% for APSI, 0.21° and 15% for MLSI, and 0.41° and 20% for OSI, respectively. These results were considered acceptable, despite indices with high MDC for MLSI (postural stability) and APSI (fall risk). CONCLUSIONS: Patients with PD have more mediolateral and anteroposterior changes in the stable and unstable conditions, respectively. These abnormal balance strategies can occur principally due to postural instability of PD. However, our results demonstrated acceptable MDCs in both conditions in all of the assessed axes. Thus, BBS should be incorporated into the clinical evaluation to help therapists to determine if intervention-induced changes in balance are clinically significant or due to measurement error. LEVEL OF EVIDENCE: II.

6.
J Appl Physiol (1985) ; 127(3): 806-815, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31268828

RESUMO

The manipulation of resistance training (RT) variables is used among athletes, recreational exercisers, and compromised populations (e.g., elderly) attempting to potentiate muscle hypertrophy. However, it is unknown whether an individual's inherent predisposition dictates the RT-induced muscle hypertrophic response. Resistance-trained young [26 (3) y] men (n = 20) performed 8 wk unilateral RT (2 times/wk), with 1 leg randomly assigned to a standard progressive RT [control (CON)] and the contralateral leg to a variable RT (VAR; modulating exercise load, volume, contraction type, and interset rest interval). The VAR leg completed all 4 RT variations every 2 wk. Bilateral vastus lateralis cross-sectional area (CSA) was measured, pre- and post-RT and acute integrated myofibrillar protein synthesis (MyoPS) rates were assessed at rest and over 48 h following the final RT session. Muscle CSA increase was similar between CON and VAR (P > 0.05), despite higher total training volume (TTV) in VAR (P < 0.05). The 0-48-h integrated MyoPS increase postexercise was slightly greater for VAR than CON (P < 0.05). All participants were considered "responders" to RT, although none benefited to a greater extent from a specific protocol. Between-subjects variability (MyoPS, 3.30%; CSA, 37.8%) was 40-fold greater than the intrasubject (between legs) variability (MyoPS, 0.08%; CSA, 0.9%). The higher TTV and greater MyoPS response in VAR did not translate to a greater muscle hypertrophic response. Manipulating common RT variables elicited similar muscle hypertrophy than a standard progressive RT program in trained young men. Intrinsic individual factors are key determinants of the MyoPS and change in muscle CSA compared with extrinsic manipulation of common RT variables.NEW & NOTEWORTHY Systematically manipulating resistance training (RT) variables during RT augments the stimulation of myofibrillar protein synthesis (MyoPS) and training volume but fails to potentiate muscle hypertrophy compared with a standard progressive RT. Any modest further MyoPS increase and higher training volumes do not reflect in a greater hypertrophic response. Between-subject variability was 40-fold greater than the variability promoted by extrinsic manipulation of RT variables, indicating that individual intrinsic factors are stronger determinants of the hypertrophic response.

7.
J Appl Physiol (1985) ; 127(1): 89-97, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31306047

RESUMO

This study had two objectives: 1) to compare the effects of 3 wk of resistance training (RT) and resistance training with instability (RTI) on evoked reflex responses at rest and during maximal voluntary isometric contraction (MVIC) of individuals with Parkinson's disease (PD) and 2) to determine the effectiveness of RT and RTI in moving values of evoked reflex responses of individuals with PD toward values of age-matched healthy control subjects (HCs) (z-score analysis). Ten individuals in the RT group and 10 in the RTI group performed resistance exercises twice a week for 3 wk, but only the RTI group included unstable devices. The HC group (n = 10) were assessed at pretest only. Evoked reflex responses at rest (H reflex and M wave) and during MVIC [supramaximal M-wave amplitude (Msup) and supramaximal V-wave amplitude (Vsup)] of the plantar flexors were assessed before and after the experimental protocol. From pretraining to posttraining, only RTI increased ratio of maximal H-reflex amplitude to maximal M-wave amplitude at rest (Hmax/Mmax), Msup, Vsup/Msup, and peak torque of the plantar flexors (P < 0.05). At posttraining, RTI was more effective than RT in increasing resting Hmax and Vsup and in moving these values to those observed in HCs (P < 0.05). We conclude that short-term RTI is more effective than short-term RT in modulating H-reflex excitability and in increasing efferent neural drive, approaching average values of HCs. Thus short-term RTI may cause positive changes at the spinal and supraspinal levels in individuals with PD. NEW & NOTEWORTHY Maximal H-reflex amplitude (Hmax) at rest and efferent neural drive [i.e., supramaximal V-wave amplitude (Vsup)] to skeletal muscles during maximal contraction are impaired in individuals with Parkinson's disease. Short-term resistance training with instability was more effective than short-term resistance training alone in increasing Hmax and Vsup of individuals with Parkinson's disease, reaching the average values of healthy control subjects.

8.
Front Physiol ; 10: 446, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31057426

RESUMO

The metabolic stress induced by blood flow restriction (BFR) during resistance training (RT) might maximize muscle growth. However, it is currently unknown whether metabolic stress are associated with muscle hypertrophy after RT protocols with high- or low load. Therefore, the aim of the study was to compare the effect of high load RT (HL-RT), high load BFR (HL-BFR), and low load BFR (LL-BFR) on deoxyhemoglobin concentration [HHb] (proxy marker of metabolic stress), muscle cross-sectional area (CSA), activation, strength, architecture and edema before (T1), after 5 (T2), and 10 weeks (T3) of training with these protocols. Additionally, we analyzed the occurrence of association between muscle deoxygenation and muscle hypertrophy. Thirty young men were selected and each of participants' legs was allocated to one of the three experimental protocols in a randomized and balanced way according to quartiles of the baseline CSA and leg extension 1-RM values of the dominant leg. The dynamic maximum strength was measured by 1-RM test and vastus lateralis (VL) muscle cross-sectional area CSA echo intensity (CSAecho) and pennation angle (PA) were performed through ultrasound images. The measurement of muscle activation by surface electromyography (EMG) and [HHb] through near-infrared spectroscopy (NIRS) of VL were performed during the training session with relative load obtained after the 1-RM, before (T1), after 5 (T2), and 10 weeks (T3) training. The training total volume (TTV) was greater for HL-RT and HL-BFR compared to LL-BFR. There was no difference in 1-RM, CSA, CSAecho, CSAecho/CSA, and PA increases between protocols. Regarding the magnitude of the EMG, the HL-RT and HL-BFR groups showed higher values than and LL-BFR. On the other hand, [HHb] was higher for HL-BFR and LL-BFR. In conclusion, our results suggest that the addition of BFR to exercise contributes to neuromuscular adaptations only when RT is performed with low-load. Furthermore, we found a significant association between the changes in [HHb] (i.e., metabolic stress) and increases in muscle CSA from T2 to T3 only for the LL-BFR, when muscle edema was attenuated.

9.
J Cachexia Sarcopenia Muscle ; 10(2): 257-262, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30816026

RESUMO

Significant muscle wasting is generally experienced by ill and bed rest patients and older people. Muscle wasting leads to significant decrements in muscle strength, cardiorespiratory, and functional capacity, which increase mortality rates. As a consequence, different interventions have been tested to minimize muscle wasting. In this regard, blood flow restriction (BFR) has been used as a novel therapeutic approach to mitigate the burden associated with muscle waste conditions. Evidence has shown that BFR per se can counteract muscle wasting during immobilization or bed rest. Moreover, BFR has also been applied while performing low intensity resistance and endurance exercises and produced increases in muscle strength and mass. Endurance training with BFR has also been proved to increase cardiorespiratory fitness. Thus, frail patients can benefit from exercising with BFR due to the lower cardiovascular and join stress compared with traditional high intensity exercises. Therefore, low intensity resistance and endurance training combined with BFR may be considered as a novel and attractive intervention to counteract muscle wasting and to decrease the burden associated with this condition.

10.
Eur J Sport Sci ; 19(8): 1092-1100, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30702985

RESUMO

The aim of the present study was to investigate if resistance training (RT), performed with individualized recovery between sessions (RT-IND), promotes greater gains in strength and muscle mass and reduces the variability on adaptations compared to RT with fixed recovery intervals (RT-FIX). Twenty young men (age 21.9 ± 3.3 years) were randomized in the RT-IND and RT-FIX groups. Five days before the beginning of the training, measurements of the root mean square of successive R-R intervals differences (RMSSD) values of each individual were performed to establish the baseline values. Before each RT session, the RMSSD values determined whether the participants from RT-IND protocol were recovered from the previous session. Participants performed the RT session only if RMSSD values had returned to the baseline, otherwise they had to wait for an additional 24 h. RT-FIX performed an RT session every 48 h. Muscle strength was measured by one-maximal repetition (1-RM) test and muscle cross-section area (CSA) of the vastus laterals by ultrasonography were assessed pre- and post-training. 1-RM values increased significantly from pre to post-training for both groups (RT-IND: 30% and RT-FIX: 42%, main time effect, P < 0001), with no significant difference between groups. Muscle CSA increased significantly from pre to post-training (RT-IND: 15.7% and RT-FIX: 15.8%, main time effect, P < 0001), with no significant difference between groups. In conclusion, RT-IND did not increase the gains in muscle strength and mass neither reduce the variability in muscle adaptations when compared to the RT-FIX.


Assuntos
Frequência Cardíaca , Força Muscular , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Adaptação Fisiológica , Adulto , Humanos , Masculino , Adulto Jovem
11.
Sports (Basel) ; 7(1)2019 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-30621334

RESUMO

This study investigated the effects of advanced training techniques (ATT) on muscular responses and if performing a second training session would negatively affect the training stimulus. Eleven strength-trained males performed a traditional strength training session (TST) and four different ATT: pre-exhaustion A (PE-A), pre-exhaustion B (PE-B), forced repetitions (FR), and super-set (SS). On day 1, SS produced lower volume load than TST, FR, and PE-B (-16.0%, p ≤ 0.03; -14.9, p ≤ 0.03 and -18.2%, p ≤ 0.01, respectively). On day 2, SS produced lower volumes than all the other ATT (-9.73⁻-18.5%, p ≤ 0.03). Additionally, subjects demonstrated lower perceived exertion on day 1 compared to day 2 (6.5 ± 0.4 AU vs. 8.7 ± 0.3 AU, p = 0.0001). For blood lactate concentration [La-] on days 1 and 2, [La-] after the tenth set was the highest compared to all other time points (baseline: 1.7 ± 0.2, fifth-set: 8.7 ± 1.0, tenth-set 9.7 ± 0.9, post-5 min: 8.7 ± 0.7 mmol∙L-1, p ≤ 0.0001). Acute muscle swelling was greater immediately and 30-min post compared to baseline (p ≤ 0.0001). On day 2, electromyography (EMG) amplitude on the clavicular head of the pectoralis major was lower for SS than TST, PE-A, and PE-B (-11.7%, p ≤ 0.01; -14.4%, p ≤ 0.009; -20.9%, p = 0.0003, respectively). Detrimental effects to the training stimulus were not observed when ATT (besides SS) are repeated. Strength trained individuals can sustain performance, compared to TST, when they are using ATT in an acute fashion. Although ATT have traditionally been used as a means to optimize metabolic stress, volume load, and neuromuscular responses, our data did not project differences in these variables compared to TST. However, it is important to note that different ATT might produce slight changes in volume load, muscle excitation, and fluid accumulation in strength-trained individuals from session to session.

12.
Appl Physiol Nutr Metab ; 44(2): 216-220, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30001503

RESUMO

We aimed to investigate the mechanisms underlying muscle growth after 12 weeks of resistance training performed with blood flow restriction (RT-BFR) and high-intensity resistance training (HRT) in older individuals. Participants were allocated into the following groups: HRT, RT-BFR, or a control group. High-throughput transcriptome sequencing was performed by the Illumina HiSeq 2500 platform. HRT and RT-BFR presented similar increases in the quadriceps femoris cross-sectional area, and few genes were differently expressed between interventions. The small differences in gene expression between interventions suggest that similar mechanisms may underpin training-induced muscle growth.


Assuntos
Envelhecimento/fisiologia , Músculo Esquelético/metabolismo , Educação Física e Treinamento , Fluxo Sanguíneo Regional/fisiologia , Treinamento de Resistência , Transcriptoma/fisiologia , Idoso , DNA/biossíntese , DNA/genética , Dieta , Feminino , Regulação da Expressão Gênica/fisiologia , Humanos , Perna (Membro)/anatomia & histologia , Perna (Membro)/fisiologia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/irrigação sanguínea , Músculo Quadríceps/fisiologia , RNA/biossíntese , RNA/genética
13.
J Strength Cond Res ; 33(4): 897-901, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30289872

RESUMO

Damas, F, Barcelos, C, Nóbrega, SR, Ugrinowitsch, C, Lixandrão, ME, Santos, LMEd, Conceição, MS, Vechin, FC, and Libardi, CA. Individual muscle hypertrophy and strength responses to high vs. low resistance training frequencies. J Strength Cond Res 33(4): 897-901, 2019-The aim of this short communication was to compare the individual muscle mass and strength gains with high (HF) vs. low (LF) resistance training (RT) frequencies using data from our previous study. We used a within-subject design in which 20 subjects had one leg randomly assigned to HF (5× per week) and the other to LF (2 or 3× per week). Muscle cross-sectional area and 1 repetition maximum were assessed at baseline and after 8 weeks of RT. HF showed a higher 8-week accumulated total training volume (TTV) (p < 0.0001) compared with LF. Muscle cross-sectional area and 1 repetition maximum values increased significantly and similarly for HF and LF protocols (p > 0.05). This short communication highlights that some individuals showed greater muscle mass and strength gains after HF (31.6 and 26.3% of individuals, respectively), other had greater gains with LF (36.8 and 15.8% of individuals, respectively), and even others showed similar responses between HF and LF, regardless of the consequent higher or lower TTV resulted from HF and LF, respectively. Importantly, individual manipulation of RT frequency can improve the intrasubject responsiveness to training, but the effect is limited to each individual's capacity to respond to RT. Finally, individual response to different frequencies and resulted TTV does not necessarily agree between muscle hypertrophy and strength gains.


Assuntos
Força Muscular , Músculo Quadríceps/anatomia & histologia , Músculo Quadríceps/fisiologia , Treinamento de Resistência/instrumentação , Adolescente , Adulto , Humanos , Masculino , Tamanho do Órgão , Distribuição Aleatória , Treinamento de Resistência/métodos , Adulto Jovem
14.
J Sport Rehabil ; 28(7): 706-710, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30040033

RESUMO

CONTEXT: Given the comparable muscle hypertrophy constantly observed between blood-flow restriction exercise (BFR-RE) and conventional resistance exercise, understanding their particular rating of perceived exertion (RPE) and pain may help to better prescribe exercise at a low-discomfort level, thus increasing its feasibility. DESIGN: Randomized crossover study. OBJECTIVE: To compare the RPE and pain response between conventional high- (HI-RE) and low-intensity resistance exercise (LI-RE) protocols to failure with a nonmuscular failure LI-RE associated with BFR-RE. PARTICIPANTS: A total of 12 men (age: 20 [3] y; body mass: 73.5 [9] kg; height: 174 [6] cm). INTERVENTIONS: Four sets of 45° leg-press exercises in 3 different conditions: (1) BFR-RE (15 repetitions; 30% 1-repetition maximum), (2) HI-RE (80% 1-repetition maximum to muscular failure), and (3) LI-RE (30% 1-repetition maximum to muscular failure). MAIN OUTCOME MEASURES: RPE and pain were assessed immediately before exercise session and after the end of each of the 4 sets. RESULTS: RPE and pain levels increased throughout the exercise sets for all RE protocols (all, Ps < .05). HI-RE and LI-RE protocols showed similar increase in RPE and pain levels during all exercise sets (P < .05); however, both protocols demonstrated higher RPE and pain response compared with BFR-RE after each of the 4 sets (all Ps < .05 between-group comparisons). CONCLUSIONS: Our results demonstrated that both HI-RE and LI-RE to muscular failure resulted in similar and significant increases in RPE and pain levels, regardless of exercise intensity. In addition, nonmuscular failure BFR-RE also increased RPE and pain response, however, to a lower extent compared with either HI-RE or LI-RE.


Assuntos
Hemodinâmica , Músculo Esquelético/fisiologia , Dor , Esforço Físico , Treinamento de Resistência , Constrição , Estudos Cross-Over , Humanos , Masculino , Força Muscular , Músculo Esquelético/irrigação sanguínea , Medição da Dor , Fluxo Sanguíneo Regional , Adulto Jovem
15.
Eur J Sport Sci ; 19(3): 287-294, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30096988

RESUMO

The aim of the present study was to investigate the acute effect of the aerobic exercise volume on maximum strength and strength-endurance performance; and possible causes of strength decrements (i.e. central and peripheral fatigue). Twenty-one moderately trained men were submitted to a maximal incremental test to determine anaerobic threshold (AnT) and maximum dynamic strength (1RM) and strength-endurance (i.e. total volume load [TV]) tests to determine their baseline strength performance. Following, subjects performed six experimental sessions: aerobic exercise sessions (continuous running at 90% AnT) with different volumes (3 km, 5 km or 7 km) followed by 1RM or strength-endurance test in the 45° leg press exercise. Maximum voluntary isometric contraction (MVIC), voluntary activation (VA) level, contractile properties, and electromyographic activity (root mean square [RMS]) of the knee extensor muscles were assessed before and after aerobic exercises and after strength tests. TV was lower after 5 km and 7 km runs than in the control condition (12% and 22%, respectively). Additionally, TV was lower after 7 km than 3 km (14%) and 5 km (12%) runs. MVIC, VA, RMS, and contractile properties were reduced after all aerobic exercise volumes (∼8%, ∼5%, ∼11% and ∼6-14%, respectively). Additionally, MVIC, VA, and contractile properties were lower after strength tests (∼15%, ∼6%, ∼9-26%, respectively). In conclusion, strength-endurance performance is impaired when performed after aerobic exercise and the magnitude of this interference is dependent on the aerobic exercise volume; and peripheral and central fatigue indices could not explain the different TV observed.


Assuntos
Exercício/fisiologia , Força Muscular , Músculo Esquelético/fisiologia , Resistência Física , Adulto , Limiar Anaeróbio , Estudos Cross-Over , Estimulação Elétrica , Humanos , Contração Isométrica , Masculino , Adulto Jovem
16.
Trials ; 19(1): 545, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30305151

RESUMO

BACKGROUND: Patients with major depression disorder presents increased rates of cognitive decline, reduced hippocampal volume, poor sleep quality, hypertension, obesity, suicidal ideation and behavior, and decreased functionality. Although continuous aerobic exercise (CAE) improves some of the aforementioned symptoms, comorbidities, and conditions, recent studies have suggested that performing aerobic exercise with motor complexity (AEMC) may be more beneficial for cognitive decline, hippocampal volume, and functionality. Therefore, this randomized controlled trial will compare the effects of CAE and AEMC on depression score, cognitive function, hippocampal volume, brain-derived neurotrophic factor expression, sleep parameters, cardiovascular risk parameters, suicidal behavior, functionality, and treatment costs in patients with depression. METHODS/DESIGN: Seventy-five medicated patients with depression will be recruited from a Basic Healthcare Unit to participate in this prospective, parallel group, single blinded, superiority, randomized controlled trial. Patients with depression according to DSM-V criteria will be balanced and randomly assigned (based on depression scores and number of depressive episodes) to a non-exercising control (C), CAE, and AEMC groups. The CAE and AEMC groups will exercise for 60 min, twice a week for 24 weeks (on non-consecutive days). Exercise intensity will be maintained between 12 and 14 points of the rating of perceived exertion scale (~ 70-80% of the maximum heart rate). The CAE group will perform a continuous aerobic exercise while the AEMC group will perform exercises with progressively increased motor complexity. Blinded raters will assess patients before and after the intervention period. The primary outcome measure will be the change in depression score measured by the Montgomery-Asberg Depression Rating Scale. Secondary outcomes will include measures of cognitive function, hippocampal volume, brain-derived neurotrophic factor expression, sleep parameters, cardiovascular risk parameters, suicidal behavior, functionality, and treatment costs. DISCUSSION: This study was selected in the call of public policy programs for the Brazilian Unified National Health System - "PPSUS 2015". To our knowledge, this is the first pragmatic trial to test the effect of adding AEMC to the pharmacological treatment of patients with depression and to evaluate the possible reductions in depression symptoms and healthcare costs. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (ReBec) - RBR-9zgxzd - Registered on 4 Jan. 2017.


Assuntos
Antidepressivos/uso terapêutico , Transtorno Depressivo Maior/terapia , Terapia por Exercício/métodos , Atividade Motora , Brasil , Terapia Combinada , Transtorno Depressivo Maior/diagnóstico , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/psicologia , Estudos de Equivalência como Asunto , Humanos , Ensaios Clínicos Pragmáticos como Assunto , Estudos Prospectivos , Método Simples-Cego , Fatores de Tempo , Resultado do Tratamento
17.
Front Physiol ; 9: 1144, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30246799

RESUMO

Caffeine (CAF) is an ergogenic aid used to improve exercise performance. Independent studies have suggested that caffeine may have the ability to increase corticospinal excitability, thereby decreasing the motor cortex activation required to generate a similar motor output. However, CAF has also been suggested to induce a prefrontal cortex (PFC) deoxygenation. Others have suggested that placebo (PLA) may trigger comparable effects to CAF, as independent studies found PLA effects on motor performance, corticospinal excitability, and PFC oxygenation. Thus, we investigated if CAF and CAF-perceived PLA may improve motor performance, despite the likely unchanged MC activation and greater PFC deoxygenation. Nine participants (26.4 ± 4.8 years old, VO2MAX of 42.2 ± 4.6 mL kg-1 min-1) performed three maximal incremental tests (MITs) in control (no supplementation) and ∼60 min after CAF and PLA ingestion. PFC oxygenation (near-infrared spectroscopy at Fp1 position), MC activation (EEG at Cz position) and vastus lateralis and rectus femoris muscle activity (EMG) were measured throughout the tests. Compared to control, CAF and PLA increased rectus femoris muscle EMG (P = 0.030; F = 2.88; d = 0.84) at 100% of the MIT, and enhanced the peak power output (P = 0.006; F = 12.97; d = 1.8) and time to exhaustion (P = 0.007; F = 12.97; d = 1.8). In contrast, CAF and PLA did not change MC activation, but increased the PFC deoxygenation as indicated by the lower O2Hb (P = 0.001; F = 4.68; d = 1.08) and THb concentrations (P = 0.01; F = 1.96; d = 0.7) at 80 and 100% the MIT duration. These results showed that CAF and CAF-perceived PLA had the ability to improve motor performance, despite unchanged MC activation and greater PFC deoxygenation. The effectiveness of CAF as ergogenic aid to improve MIT performance was challenged.

18.
Eur J Appl Physiol ; 118(12): 2607-2616, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30196447

RESUMO

BACKGROUND: Gene expression is an important process underpinning the acute and chronic adaptive response to resistance exercise (RE) training. PURPOSE: To investigate the effect of training status on vastus lateralis muscle global transcriptome at rest and following acute RE. METHODS: Muscle biopsies of nine young men (age: 26(2) years; body mass: 69(9) kg; height 172(6) cm) who undertook RE training for 10 weeks were collected pre and 24 h post-RE in the untrained (W1) and trained (W10) states and analysed using microarray. Tests of differential expression were conducted for rested and after RE contrasts in both training states. To control for false discovery rate (FDR), multiple testing correction was performed at a cut-off of FDR < 0.05. RESULTS: Unaccustomed RE (at W1) upregulated muscle gene transcripts related to stress (e.g., heat shock proteins), damage and inflammation, structural remodelling, protein turnover and increased translational capacity. Trained muscles (at W10) showed changes in the transcriptome signature regarding the regulation of energy metabolism, favouring a more oxidative one, upregulated antioxidant- and immune-related genes/terms, and gene transcripts related to the cytoskeleton and extracellular matrix, muscle contraction, development and growth. CONCLUSIONS: These results highlight that chronic repetition of RE changes muscle transcriptome response towards a more refined response to RE-induced stress.


Assuntos
Músculo Esquelético/metabolismo , Treinamento de Resistência , Estresse Fisiológico , Transcriptoma , Adulto , Humanos , Masculino , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia
19.
Eur J Sport Sci ; 18(8): 1077-1082, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29852092

RESUMO

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.


Assuntos
Adaptação Fisiológica , Força Muscular , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Adulto , Humanos , Hipertrofia , Masculino , Músculo Esquelético/crescimento & desenvolvimento , Fatores de Tempo , Adulto Jovem
20.
PM R ; 10(11): 1145-1152, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29753113

RESUMO

BACKGROUND: Patients with Parkinson disease (PD) present cardiovascular autonomic dysfunction that impairs blood pressure control. However, cardiovascular responses during resistance exercise are unknown in these patients. OBJECTIVE: To investigate cardiovascular responses during resistance exercise performed with different muscle masses in patients with PD. DESIGN: Prospective, repeated-measures. SETTING: Exercise Hemodynamic Laboratory, School of Physical Education and Sport, University of São Paulo. PARTICIPANTS: Thirteen patients with PD (4 women, 62.7 ± 1.3 years, stages 2-3 of the modified Hoehn and Yahr scale; "on" state of medication) and 13 paired control patients without PD (7 women, 66.2 ± 2.0 years). INTERVENTIONS: Both groups performed, in a random order, bilateral and unilateral knee extension exercises (2 sets, 10-12 maximal repetition, 2-minute intervals). MAIN OUTCOME MEASUREMENTS: Systolic blood pressure (SBP) and heart rate (HR) were assessed before (pre) and during the exercises. RESULTS: Independent of set and exercise type, SBP and HR increases were significantly lower in PD than the control group (combined values: +45 ± 2 versus +73 ± 4 mm Hg and +18 ± 1 versus +31 ± 2 bpm, P = .003 and .007, respectively). Independently of group and set, the SBP increase was greater in the bilateral than the unilateral exercise (combined values: +63 ± 4 versus +54 ± 3 mm Hg, P = .002), whereas the HR increase was similar. In addition, independently of group and exercise type, the SBP increase was greater in the second than the first set (combined values: +56 ± 4 versus +61 ± 4 mm Hg, P = .04), whereas the HR increases were similar. CONCLUSIONS: Patients with PD present attenuated increases in SBP and HR during resistance exercise in comparison with healthy subjects. These results support that resistance exercise is safe and well tolerated for patients with PD from a cardiovascular point of view supporting its recommendation for this population. LEVEL OF EVIDENCE: II.


Assuntos
Sistema Nervoso Autônomo/fisiopatologia , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Doença de Parkinson/fisiopatologia , Treinamento de Resistência , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA