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1.
J Musculoskelet Neuronal Interact ; 24(1): 38-46, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427367

RESUMO

BFR) applied during sprint interval training (SIT) on performance and neuromuscular function. METHODS: Fifteen men completed a randomized bout of SIT with CBFR, IBFR, and without BFR (No-BFR), consisting of 2, 30-s maximal sprints on a cycle ergometer with a resistance of 7.5% of body mass. Concentric peak torque (CPT), maximal voluntary isometric contraction (MVIC) torque, and muscle thickness (MT) were measured before and after SIT, including surface electromyography (sEMG) recorded during the strength assessments. Peak and mean revolutions per minute (RPM) were measured during SIT and power output was examined relative to physical working capacity at the fatigue threshold (PWCFT). RESULTS: CPT and MVIC torque decreased from pre-SIT (220.3±47.6 Nm and 355.1±72.5 Nm, respectively) to post-SIT (147.9±27.7 Nm and 252.2±45.5 Nm, respectively, all P<0.05), while MT increased (1.77±0.31 cm to 1.96±0.30 cm). sEMG mean power frequency decreased during CPT (-12.8±10.5%) and MVIC (-8.7±10.2%) muscle actions. %PWCFT was greater during No-BFR (414.2±121.9%) than CBFR (375.9±121.9%). CONCLUSION: SIT with or without BFR induced comparable alterations in neuromuscular fatigue and sprint performance across all conditions, without affecting neuromuscular function.


Assuntos
Treinamento Intervalado de Alta Intensidade , Músculo Esquelético , Humanos , Masculino , Eletromiografia , Contração Isométrica/fisiologia , Fadiga Muscular , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Torque
2.
Eur J Appl Physiol ; 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39162881

RESUMO

PURPOSE: Resistance exercise can attenuate muscular impairments associated with multiple sclerosis (MS), and blood flow restriction (BFR) may provide a viable alternative to prescribing heavy training loads. The purpose of this investigation was to examine the progression of upper and lower body low-load (30% of one-repetition maximum [1RM]) resistance training (RT) with BFR applied intermittently during the exercise intervals (RT + BFR) versus volume-matched heavy-load (65% of 1RM) RT. METHODS: Men and women with MS (n = 16) were randomly assigned to low-load RT + BFR (applied intermittently) or heavy-load RT and completed 12 weeks (2 × /week) of RT that consisted of bilateral chest press, seated row, shoulder press, leg press, leg extension, and leg curl exercises. Exercise load, tonnage, and rating of perceived exertion were assessed at baseline and every 6 weeks. RESULTS: Training load increased to a greater extent and sometimes earlier for RT + BFR (57.7-106.3%) than heavy-load RT (42.3-54.3%) during chest press, seated row, and leg curl exercises, while there were similar increases (63.5-101.1%) for shoulder press, leg extension, and leg press exercises. Exercise tonnage was greater across all exercises for RT + BFR than heavy-load RT, although tonnage only increased during the chest press (70.7-80.0%) and leg extension (89.1%) exercises. Perceptions of exertion (4.8-7.2 au) and compliance (97.9-99.0%) were similar for both interventions. CONCLUSION: The training-induced increases in load, high compliance, and moderate levels of exertion suggested that RT + BFR and heavy-load RT are viable interventions among people with MS. RT + BFR may be a preferred modality if heavy loads are not well tolerated and/or to promote early-phase training responses.

3.
J Strength Cond Res ; 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39178106

RESUMO

ABSTRACT: Lubiak, SM, Lawson, JE, Gonzalez Rojas, DH, Proppe, CE, Rivera, PM, Hammer, SM, Trevino, MA, Dinyer-McNeely, TK, Montgomery, TR, Olmos, AA, Sears, KN, Bergstrom, HC, Succi, PJ, Keller, JL, and Hill, EC. A moderate blood flow restriction pressure does not affect maximal strength or neuromuscular responses. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to examine the acute effects of blood flow restriction (BFR) applied at 60% of total arterial occlusion pressure (AOP) on maximal strength. Eleven college-aged female subjects completed two testing sessions of maximal unilateral concentric, isometric, and eccentric leg extension muscle actions performed with and without BFR. Separate 3 (mode [isometric, concentric, eccentric]) × 2 (condition [BFR, no BFR]) × 2 (visit [2, 3]) repeated-measures analysis of variances were used to examine mean differences in maximal strength, neuromuscular function, rating of perceived exertion (RPE), and pain. For maximal strength (collapsed across condition and visit), isometric (128.5 ± 22.7 Nm) and eccentric (114.5 ± 35.4 Nm) strength were greater than concentric maximal strength (89.3 ± 22.3 Nm) (p < 0.001-0.041). Muscle excitation relative (%) to isometric non-BFR was greater during the concentric (108.6 ± 31.5%) than during the eccentric (86.7 ± 29.2%) (p = 0.045) assessments but not different than isometric (93.4 ± 17.9%) (p = 0.109) assessments, collapsed across condition and visit. For RPE, there was an interaction such that RPE was greater during non-BFR (4.3 ± 1.7) than during BFR (3.7 ± 1.7) (p = 0.031) during the maximal concentric strength assessments. Furthermore, during maximal strength assessments performed with BFR, isometric RPE (5.8 ± 1.9) was greater than concentric (3.7 ± 1.7) (p = 0.005) and eccentric (4.6 ± 1.9) (p = 0.009) RPE. Finally, pain was greater during the isometric (2.8 ± 2.1 au) than during the concentric (1.8 ± 1.5 au) (p = 0.016), but not eccentric, maximal strength assessments (2.1 ± 1.6 au) (p = 0.126), collapsed across condition and visit. The application of BFR at 60% AOP did not affect concentric, isometric, or eccentric maximal strength or neuromuscular function. Trainers, clinicians, and researchers can prescribe exercise interventions relative to a restricted (when using a moderate AOP) or nonrestricted assessment of maximal strength.

4.
J Musculoskelet Neuronal Interact ; 23(2): 165-174, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-37259656

RESUMO

OBJECTIVES: The purpose of this investigation was to examine the acute effects of low-load blood flow restriction (LLBFR) and low-load (LL) resistance exercise on muscle excitation, neuromuscular efficiency, and average torque. METHODS: Eleven men (age±SD=22±3yrs) randomly performed LLBFR and LL that consisted of 30 unilateral leg extensions at 30% of one-repetition maximum while surface electromyography (sEMG) and torque were simultaneously assessed. Polynomial regression analyses and slope comparisons were performed to examine patterns of responses and rates of change. RESULTS: sEMG amplitude increased for LLBFR (9 of 11) and LL (8 of 11) and between composite responses (R2=0.939-0.981). For LLBFR, sEMG amplitude increased to a greater extent for 5 of the 11 individual and for the composite responses. Similarly, neuromuscular efficiency decreased for LLBFR (8 of 11) and LL (5 of 11) as well as the composite responses r2=0.902-0.929, but the decrease was larger for LLBFR than LL for the individual (4 of 11) responses. For average submaximal concentric torque, there were individual increases, decreases, and no changes for the composite responses (R2=0.198-0.325). CONCLUSION: LLBFR elicited greater fatigue-induced increases in muscle excitation and decreases in neuromuscular efficiency than LL, but neither LLBFR nor LL affected average submaximal concentric torque.


Assuntos
Músculo Esquelético , Treinamento Resistido , Humanos , Masculino , Eletromiografia , Exercício Físico/fisiologia , Músculo Esquelético/fisiologia , Torque , Adulto Jovem , Adulto
5.
J Strength Cond Res ; 37(10): e546-e554, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37639655

RESUMO

ABSTRACT: Wizenberg, AM, Gonzalez-Rojas, D, Rivera, PM, Proppe, CE, Laurel, KP, Stout, JR, Fukuda, DH, Billaut, F, Keller, JL, and Hill, EC. Acute effects of continuous and intermittent blood flow restriction on sprint interval performance and muscle oxygen responses. J Strength Cond Res 37(10): e546-e554, 2023-This investigation aimed to examine the acute effects of continuous and intermittent blood flow restriction (CBFR and IBFR, respectively) during sprint interval training (SIT) on muscle oxygenation, sprint performance, and ratings of perceived exertion (RPE). Fifteen men (22.6 ± 2.4 years; 176 ± 6.3 cm; 80.0 ± 12.6 kg) completed in random order a SIT session with CBFR, IBFR (applied during rest), and no blood flow restriction (NoBFR). Each SIT session consisted of two 30-second all-out sprint tests separated by 2 minutes. Peak power (PP), total work (TW), sprint decrement score (S dec ), RPE, and muscle oxygenation were measured during each sprint. A p value ≤0.05 was considered statistically significant. PP decreased to a greater extent from sprint 1 to sprint 2 during CBFR (25.5 ± 11.9%) and IBFR (23.4 ± 9.3%) compared with NoBFR (13.4 ± 8.6%). TW was reduced similarly (17,835.6 ± 966.2 to 12,687.2 ± 675.2 J) from sprint 1 to sprint 2 for all 3 conditions, but TW was lower (collapsed across time) for CBFR (14,320.7 ± 769.1 J) than IBFR (15,548.0 ± 840.5 J) and NoBFR (15,915.4 ± 771.5 J). There were no differences in S dec (84.3 ± 1.7%, 86.1 ± 1.5%, and 87.2 ± 1.1% for CBFR, IBFR, and NoBFR, respectively) or RPE, which increased from sprint 1 (8.5 ± 0.3) to sprint 2 (9.7 ± 0.1). Collective muscle oxygenation responses increased across time and were similar among conditions, whereas increases in deoxy[heme] and total[heme] were greatest for CBFR. Applying BFR during SIT induced greater decrements in PP, and CBFR resulted in greater decrements in work across repeated sprints. The larger increases in deoxy[heme] and total[heme] for CBFR suggested it may induce greater metabolite accumulation than IBFR and NoBFR when combined with SIT.


Assuntos
Treinamento Intervalado de Alta Intensidade , Músculos , Humanos , Masculino , Heme , Oxigênio , Descanso , Adulto Jovem
6.
J Neurophysiol ; 128(1): 73-85, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35704398

RESUMO

The purpose of this study was to examine the acute effects of low-load blood flow restriction (LLBFR) and low-load non-BFR (LL) on neuromuscular function after a bout of standardized fatiguing leg extension muscle actions. Fourteen men (mean age ± SD = 23 ± 4 yr) volunteered to participate in this investigation and randomly performed LLBFR and LL on separate days. Resistance exercise consisted of 75 isotonic unilateral leg extension muscle actions performed at 30% of one-repetition maximum. Before (pretest) and after (posttest) performance of each bout of exercise, strength and neural assessments were determined. There were no pretest to posttest differences between LLBFR and LL for maximal voluntary isometric contraction (MVIC) torque or V wave/M wave responses (muscle compound action potentials assessed during a superimposed MVIC muscle action), which exhibited decreases (collapsed across condition) of 41.2% and 26.2%, respectively. There were pretest to posttest decreases in peak twitch torque (36.0%) and surface electromyography amplitude (sEMG) (29.5%) for LLBFR but not LL and larger decreases in voluntary activation for LLBFR (11.3%) than for LL (4.5%). These findings suggested that LLBFR elicited greater fatigue-induced decreases in several indexes of neuromuscular function relative to LL. Despite this, both LLBFR and LL resulted in similar decrements in performance as assessed by maximal strength.NEW & NOTEWORTHY The application of blood flow restriction induces greater acute neuromuscular fatigue relative to nonrestricted conditions. Resistance exercise with blood flow restriction elicited a greater reduction in twitch responses. These neuromuscular differences might explain the more favorable adaptations achieved with blood flow restriction that are likely a function of metabolic stress and subsequent changes in efferent neural drive.


Assuntos
Fadiga Muscular , Treinamento Resistido , Humanos , Contração Isométrica/fisiologia , Masculino , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Treinamento Resistido/métodos , Torque
7.
Res Q Exerc Sport ; : 1-11, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39231592

RESUMO

Purpose: There is conflicting evidence related to the prevalence and magnitude of exercise-induced muscle damage (EIMD) following four sets to volitional failure with BFR (BFR-F) or 75 total repetitions with BFR (1 × 30, 3 × 15, BFR-75). The purpose of this investigation was to examine muscle swelling, peak torque, and neuromuscular responses following BFR-75 and BFR-F. Methods: Thirteen untrained women completed unilateral isokinetic (120°s-1) leg extensions concentric-eccentric at 30% of their maximal voluntary isometric contraction (MVIC) using BFR-75 and BFR-F protocols, separated by 15 minutes. Ultrasound was used to assess muscle thickness, cross sectional area, and echo intensity of the rectus femoris and vastus lateralis before, 0-, 24-, 48-, 72-, and 96-hours post-exercise. Peak torque and surface electromyography (sEMG) were recorded during MVICs before, 24-, 48-, 72-, and 96-hours post-exercise to determine sEMG amplitude, frequency, and neuromuscular efficiency. Results: There were no differences between conditions. Collapsed across conditions, muscle thickness and cross-sectional area increased at 0-hours for the rectus femoris (2.5 ± 0.4, 2.8 ± 0.4 cm, 10.6 ± 1.8, 12.1 ± 1.8 cm2, respectively) and vastus lateralis (2.1 ± 0.5, 2.5 ± 0.7 cm; 22.2 ± 3.9, 25.1 ± 4.5 cm2, respectively), but returned to baseline at 24-hours. There were no changes in echo intensity, sEMG amplitude, sEMG frequency, or neuromuscular efficiency. MVIC peak torque increased relative to pre-exercise at 24-, 48-, 72-, and 96-hours (159.9 ± 34.9, 171.4 ± 30.1-179.1 ± 35.6 Nm). Conclusion: These results suggest that BFR-75 and BFR-F did not cause EIMD but caused an acute increase in muscle swelling that returned to baseline 24-hours post-exercise.

8.
J Sports Med Phys Fitness ; 64(9): 880-888, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38863419

RESUMO

BACKGROUND: There is conflicting evidence regarding the presence and magnitude of exercise-induced muscle damage (EIMD) following low-load resistance training with blood flow restriction (LL+BFR), which may be related to the protocol implemented or exercise volume. Therefore, the purpose of this investigation was to examine the effects of a 75 repetition (BFR-75) (1×30, 3×15) and four sets to volitional failure (BFR-4x) protocols on indices of EIMD among untrained men. METHODS: Twelve males with no history of lower-body resistance training during the previous six months volunteered for this investigation. One leg was randomly assigned to BFR-75, and the other to BFR-4x. Participants performed isokinetic, unilateral, concentric-eccentric, leg extension muscle actions at 30% of maximal strength with BFR. Indices of EIMD (limb circumference, perceived muscle soreness, pain pressure threshold [PPT], passive range of motion, and maximal strength [MVIC]) were recorded before exercise and 0, 24, 48, 72, and 96-hours post-exercise for each protocol. RESULTS: There were no significant changes (P>0.05) in limb circumference, PPT, passive range of motion, or MVIC. For both BFR-75 and BFR-4x, perceived muscle soreness increased (P<0.001) similarly 24- (2.5±1.7 AU) and 48-hours (1.9±1.7 AU) post-exercise. CONCLUSIONS: There was an increase in muscle soreness 24-48 hours post-exercise for both conditions, which may be due to metabolic stress, but this did not affect the force-generating capacity of the muscle (MVIC), suggesting minimal EIMD. The conflicting evidence of EIMD following LL+BFR may be related to differences in restriction time or overall exercise time.


Assuntos
Força Muscular , Músculo Esquelético , Mialgia , Treinamento Resistido , Humanos , Masculino , Treinamento Resistido/métodos , Músculo Esquelético/irrigação sanguínea , Mialgia/fisiopatologia , Mialgia/etiologia , Força Muscular/fisiologia , Adulto Jovem , Adulto , Amplitude de Movimento Articular/fisiologia , Fluxo Sanguíneo Regional/fisiologia
9.
Physiol Meas ; 45(4)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38507792

RESUMO

Objective. Surface mechanomyography (sMMG) can measure oscillations of the activated muscle fibers in three axes (i.e.X,Y, andZ-axes) and has been used to describe motor unit activation patterns (X-axis). The application of blood flow restriction (BFR) is common in exercise studies, but the cuff may restrict muscle fiber oscillations. Therefore, the purpose of this investigation was to examine the acute effects of submaximal, fatiguing exercise with and without BFR on sMMG amplitude in theX,Y, andZ-axes among female participants.Approach. Sixteen females (21 ± 1 years) performed two separate exercise bouts to volitional exhaustion that consisted of unilateral, submaximal (50% maximal voluntary isometric contraction [MVIC]) intermittent, isometric, leg extensions with and without BFR. sMMG was recorded and examined across percent time to exhaustion (%TTE) in 20% increments. Separate 2-way repeated measures ANOVA models were constructed: (condition [BFR, non-BFR]) × (time [20, 40, 60, 80, and 100% TTE]) to examine absolute (m·s-2) and normalized (% of pretest MVIC) sMMG amplitude in theX-(sMMG-X),Y-(sMMG-Y), andZ-(sMMG-Z) axes.Main results. The absolute sMMG-X amplitude responses were attenuated with the application of BFR (mean ± SD = 0.236 ± 0.138 m·s-2) relative to non-BFR (0.366 ± 0.199 m·s-2, collapsed across time) and for sMMG-Y amplitude at 60%-100% of TTE (BFR range = 0.213-0.232 m·s-2versus non-BFR = 0.313-0.445 m·s-2). Normalizing sMMG to pretest MVIC removed most, but not all the attenuation which was still evident for sMMG-Y amplitude at 100% of TTE between BFR (72.9 ± 47.2%) and non-BFR (98.9 ± 53.1%). Interestingly, sMMG-Z amplitude was not affected by the application of BFR and progressively decreased across %TTE (0.332 ± 0.167 m·s-2to 0.219 ± 0.104 m·s-2, collapsed across condition.)Significance. The application of BFR attenuated sMMG-X and sMMG-Y amplitude, although normalizing sMMG removed most of this attenuation. Unlike theXandY-axes, sMMG-Z amplitude was not affected by BFR and progressively decreased across each exercise bout potentially tracking the development of muscle fatigue.


Assuntos
Fadiga Muscular , Treinamento Resistido , Humanos , Feminino , Fadiga Muscular/fisiologia , Exercício Físico/fisiologia , Contração Isométrica/fisiologia , Fluxo Sanguíneo Regional , Modalidades de Fisioterapia , Músculo Esquelético/fisiologia , Eletromiografia , Treinamento Resistido/métodos
10.
Eur J Sport Sci ; 23(8): 1629-1637, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36825621

RESUMO

The purpose of this investigation was to examine neuromuscular function, muscle fatigue, rating of perceived exertion (RPE), and muscle swelling between isokinetic and isotonic leg extensions with blood flow restriction (BFR). Fourteen (21 ± 2years; 160cm ± 3.8; 61kg ± 9.1) trained women performed 75 (1 × 30,3 × 15) submaximal (30% of maximal strength), unilateral, isokinetic and isotonic leg extensions with BFR (60% of total arterial occlusion pressure). Before and after exercise, subjects performed maximal voluntary isometric contractions (MVIC) and muscle thickness (MT) was assessed with ultrasound. RPE was recorded across all sets and surface electromyography (EMG) was assessed during the MVIC muscle actions. Separate repeated measures ANOVAs were used to examine MVIC, MT, RPE and neuromuscular function. There were greater reductions in MVIC torque and EMG mean power frequency following isotonic (46.2 ± 17.1%; 16.4 ± 7.9%) than isokinetic (17.9 ± 10.9%;6.5 ± 6.3%). RPE was also higher during isotonic (7.5 ± 2.2), than isokinetic (5.7 ± 1.9). There were no differences in EMG amplitude or MT increases (20 ± 2.1%) between conditions. Isotonic BFR elicited greater fatigue-induced decreases in muscular strength and greater RPE than isokinetic BFR, but similar MT and muscle excitation responses for both conditions. Therefore, both isokinetic and isotonic may induce similar acute physiological responses, but isotonic BFR was associated with greater muscle fatigue and perceived effort.HighlightsExercise modality affects the fatigue and perceptual responses when applying blood flow restriction.Despite greater utility, isotonic blood flow restriction was associated greater fatigue and perceived effort.Isotonic and isokinetic blood flow restriction elicited comparable neural changes.


Assuntos
Fadiga Muscular , Músculo Esquelético , Humanos , Feminino , Músculo Esquelético/fisiologia , Fadiga Muscular/fisiologia , Eletromiografia , Hemodinâmica , Exercício Físico/fisiologia , Contração Isométrica/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Torque
11.
Int J Exerc Sci ; 16(1): 293-303, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37113263

RESUMO

Applying blood flow restriction (BFR) during resistance exercise is a potent stimulus of muscular adaption, but there is little direct comparison of its effect on neuromuscular function. The purpose of this investigation was to compare surface electromyography amplitude and frequency responses during a 75 (1 × 30, 3 × 15) repetition bout (BFR-75) of BFR to 4 sets to failure (BFR-F). Twelve women (mean ± SD age = 22 ± 4 years; body mass = 72 ± 14.4 kg; height = 162.1 ± 4.0 cm) volunteered for the investigation. One leg was randomly assigned to complete BFR-75 and the other to BFR-F. Each leg performed isokinetic, unilateral, concentric-eccentric, leg extension at 30% of maximal strength while surface electromyographic (sEMG) data was recorded. More repetitions (p = 0.006) were completed during set 2 for BFR-F (21.2 ± 7.4) than BFR-75 (14.7 ± 1.2), but there were no other between condition differences for set 1 (29.8 ± 0.9 vs 28.9 ± 10.1), set 3 (14.4 ± 1.4 vs 17.1 ± 6.9), or set 4 (14.8 ± 0.9 vs 16.3 ± 7.0). Collapsed across condition, normalized sEMG amplitude increased (p = 0.014, 132.66 ± 14.03% to 208.21 ± 24.82%) across the first three sets of exercise then plateaued, while normalized sEMG frequency decreased (p = 0.342, 103.07 ± 3.89% to 83.73 ± 4.47%) across the first two sets then plateaued. The present findings indicated that BFR-75 and BFR-F elicited similar acute neuromuscular fatigue responses. The plateau in amplitude and frequency suggested that maximal motor unit excitation and metabolic buildup may be maximized after two to three sets of BFR-75 and BFR-F.

12.
Eur J Sport Sci ; 23(10): 1993-2001, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37032512

RESUMO

ABSTRACTThere is conflicting evidence regarding the prevalence and magnitude of exercise-induced muscle damage (EIMD) following low-load resistance exercise with blood flow restriction (LL + BFR) that may be related to exercise protocols. The purpose of this investigation was to examine the effects of 75-repetition (BFR-75) (1 × 30, 3 × 15) and 4 sets to failure (BFR-4x) protocols on indices of EIMD among untrained women. Thirteen women completed this investigation. One leg was randomly assigned to BFR-75 and the other to BFR-4x. Each leg performed isokinetic, unilateral, concentric-eccentric, leg extension muscle actions at 30% of maximal strength. Indices of EIMD (muscle soreness, range of motion [ROM], limb circumference, pain pressure threshold [PPT], and maximal voluntary isometric contraction [MVIC]) were recorded before exercise, 0-, 24-, 48-, 72-, and 96-hours post-exercise. There were no changes for ROM, circumference, or PPT. Muscle soreness increased similarly in both conditions 0-, 24-, and 48-hours post-exercise and MVIC increased 24-, 48-, 72-, and 96-hours post-exercise. These findings suggested BFR-75 and BFR-4x were not associated with EIMD and elicited similar physiological responses. The increases in muscle soreness may be due to metabolic stress associated with LL + BFR protocols apart from EIMD.


HighlightsThere was no evidence of significant exercise-induced muscle damage following low-load resistance exercise with blood flow restriction completed failure and non-failure.Muscle function was not impaired 24-96 h post-exercise for either protocol.Low-load resistance exercise with blood flow restriction using a 75-repetition and 4 sets to volitional failure protocol resulted in similar physiological responses to exercise.There may be higher levels of metabolic stress which may increase muscle soreness following low-load resistance exercise with blood flow restriction.


Assuntos
Mialgia , Treinamento Resistido , Humanos , Feminino , Terapia de Restrição de Fluxo Sanguíneo , Músculo Esquelético , Contração Isométrica , Perna (Membro) , Fluxo Sanguíneo Regional/fisiologia , Treinamento Resistido/métodos
13.
High Alt Med Biol ; 23(1): 18-25, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34936812

RESUMO

Rivera, Paola M., Chris E. Proppe, Esther Beltran, and Ethan C. Hill. Acute effects of local ischemic hypoxia and systemic hypoxemia on neuromuscular and cognitive function. High Alt Med Biol. 23:18-25, 2022. Background: The application of blood flow restriction (BFR) induces local ischemic hypoxia within the muscle(s) distal to the restriction device. Systemic hypoxemia via oxygen or barometric pressure manipulation achieves whole-body hypoxia and thus may be a more potent exercise adjunct than BFR. Therefore, the purpose of this study was to examine the acute effects of local ischemic hypoxia versus systemic hypoxemia on maximal voluntary isometric contraction (MVIC) torque, electromyographic amplitude (EMG AMP), EMG mean power frequency (MPF), and cognition. Materials and Methods: Twelve recreationally trained women (mean age ± standard deviation = 21 ± 1.6 years) performed 75 submaximal (1 × 30, 3 × 15) unilateral leg extension muscle actions under normoxia, local ischemic hypoxia, and systemic hypoxemia. Before and immediately after the 75 repetitions, MVIC muscle actions were performed, and surface EMG was simultaneously assessed from the vastus lateralis. Cognitive function was assessed immediately after each exercise using the Automated Neuropsychological Assessment Metrics (ANAM). Separate repeated-measures analyses of variance (ANOVAs) were performed to examine changes in MVIC, reaction time, EMG AMP, and EMG MPF responses during the MVIC muscle actions. Results: There were no significant (p = 0.21-0.953) Condition × Time interactions for MVIC, EMG AMP, or EMG MPF but a significant (p < 0.001-0.005) main effect for the Time collapsed across Condition for MVIC torque (pretest 238.8 ± 19.5, posttest 212.7 ± 20.1 Nm) and EMG MPF (88.5% ± 1.4% of pretest). There were no significant (p = 0.503) differences in reaction time among Conditions. Conclusions: The findings of the present study suggest that all three conditions elicited comparable acute changes in performance as assessed by MVIC torque that were associated with no changes in muscle activation but decrease in action potential conduction velocity. Therefore, the application of local ischemic hypoxia or systemic hypoxemia during low-load resistance exercise can be used to elicit similar acute physiological responses and not adversely affect cognitive function relative to nonhypoxic conditions.


Assuntos
Contração Isométrica , Músculo Esquelético , Cognição , Eletromiografia , Feminino , Humanos , Hipóxia , Contração Isométrica/fisiologia , Torque
14.
Rev. méd. hondur ; 89(1): 29-37, 2021. tab
Artigo em Espanhol | LILACS | ID: biblio-1283000

RESUMO

Antecedentes: La prevalencia mundial de discapa- cidad en adultos mayores oscila entre 29.5% y 43.4% en países de ingreso alto/bajo (OMS 2011). Objetivo: Determinar la preva- lencia de discapacidad y factores asociados en adultos mayores, Honduras, 2014-2015. Métodos: Estudio descriptivo transversal con análisis de asociación. Estudiantes de último año, Carrera de Medicina, Universidad Nacional Autónoma de Honduras, realizaron búsqueda activa de 50 participantes ≥60 años de edad. Se aplicaron dos instrumentos, uno para búsqueda activa y otro para caracterizar al participante con/sin discapacidad permanente ≥1 año de evolu- ción. Se evaluó limitación de actividad y restricción de participación ≤30 días utilizando la Clasiicación Internacional del Funcionamien- to, Discapacidad y Salud (CIF) y cuestionario WHODAS 2.0 (OMS). Se realizó análisis univariado (frecuencias, porcentajes, prevalen- cias, IC95%) y análisis bivariado (diferencia de proporciones); valor p<0.05 se consideró signiicativo). Resultados: De un total de 5,126 participantes ≥60 años de edad, 3,017 (58.9%) mujeres, edad pro- medio 73.6 años (rango 60-106), la prevalencia de discapacidad fue 51.2% (2,627/5,126); discapacidad grado leve se presentó en 1,893 (72.1%). Las estructuras relacionadas con movimiento (75.5%) y función esquelética (72.6%) fueron las más afectadas. La limitación de moverse (93.4%) y la restricción en invertir dinero propio y fami- liar en su estado de salud (86.8%) fueron las más frecuentes. Los factores sexo femenino, edad>70 años, escolaridad <6 años, enfer- medades crónicas, trauma, accidente o violencia podrían estar aso- ciados a discapacidad; todos p<0.01. Discusión: La discapacidad en adultos mayores se asoció a algunas condiciones prevenibles. Es apremiante implementar programas de envejecimiento saludable en Honduras...(AU)


Assuntos
Humanos , Masculino , Feminino , Idoso , Idoso de 80 Anos ou mais , Pessoas com Deficiência/estatística & dados numéricos , Avaliação da Deficiência , Saúde Pública , Doença Crônica
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