Blood Flow Restriction Alters Motor Unit Behavior During Resistance Exercise

Abstract

We aimed to determine whether blood flow restriction (BFR) alters the characteristics of individual motor units during low-intensity (LI) exercise. Eight men (26.0±3.8 yrs) performed 5 sets of 15 knee extensions at 20% of one-repetition maximum (with and without BFR). Maximal isometric voluntary contractions (MVC) were performed before and after exercise to quantify force decrement. Submaximal isometric voluntary contractions were additionally performed for 18 s, matching trapezoidal target-force trajectories at 40% pre-MVC. EMG activity was recorded from the vastus lateralis muscle. Then, signals were decomposed to extract motor unit recruitment threshold, firing rates and action potential amplitudes (MUAP). Force decrement was only seen after LI BFR exercise (–20.5%; p<0.05). LI BFR exercise also induced greater decrements in the linear slope coefficient of the regression lines between motor unit recruitment threshold and firing rate (BFR: –165.1±120.4 vs. non-BFR: –44.4±33.1%, p<0.05). Finally, there was a notable shift towards higher values of firing rate and MUAP amplitude post-LI BFR exercise. Taken together, our data indicate that LI BFR exercise increases the activity of motor units with higher MUAP amplitude. They also indicate that motor units with similar MUAP amplitudes become activated at higher firing rates post-LI BFR exercise.

Key words

KAATSU - muscle strength - intramuscular coordination - resistance exercise

• References

• 1 Cook SB, Murphy BG, Labarbera KE. Neuromuscular function after a bout of low-load blood flow-restricted exercise. Med Sci Sports Exerc 2013; 45: 67-74
• 2 Fahs CA, Loenneke JP, Thiebaud RS, Rossow LM, Kim D, Abe T, Beck TW, Feeback DL, Bemben DA, Bemben MG. Muscular adaptations to fatiguing exercise with and without blood flow restriction. Clin Physiol Funct Imaging 2015; 35: 167-176
• 3 Karabulut M, Cramer JT, Abe T, Sato Y, Bemben MG. Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction. J Electromyogr Kinesiol 2010; 20: 440-447
• 4 Moritani T, Sherman WM, Shibata M, Matsumoto T, Shinohara M. Oxygen availability and motor unit activity in humans. Eur J Appl Physiol Occup Physiol 1992; 64: 552-556
• 5 Shinohara M, Kouzaki M, Yoshihisa T, Fukunaga T. Efficacy of tourniquet ischemia for strength training with low resistance. Eur J Appl Physiol Occup Physiol 1998; 77: 189-191
• 6 Takarada Y, Nakamura Y, Aruga S, Onda T, Miyazaki S, Ishii N. Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. J Appl Physiol 2000; 88: 61-65
• 7 Takarada Y, Sato Y, Ishii N. Effects of resistance exercise combined with vascular occlusion on muscle function in athletes. Eur J Appl Physiol 2002; 86: 308-314
• 8 Moore DR, Burgomaster KA, Schofield LM, Gibala MJ, Sale DG, Phillips SM. Neuromuscular adaptations in human muscle following low intensity resistance training with vascular occlusion. Eur J Appl Physiol 2004; 92: 399-406
• 9 De Luca CJ, Adam A, Wotiz R, Gilmore LD, Nawab SH. Decomposition of surface EMG signals. J Neurophysiol 2006; 96: 1646-1657
• 10 Nawab SH, Chang SS, De Luca CJ. High-yield decomposition of surface EMG signals. Clin Neurophysiol 2010; 121: 1602-1615
• 11 Adam A, De Luca CJ. Recruitment order of motor units in human vastus lateralis muscle is maintained during fatiguing contractions. J Neurophysiol 2003; 90: 2919-2927
• 12 Contessa P, De Luca CJ, Kline JC. The compensatory interaction between motor unit firing behavior and muscle force during fatigue. J Neurophysiol 2016; 116: 1579-1585
• 13 Bigland-Ritchie BR, Dawson NJ, Johansson RS, Lippold OC. Reflex origin for the slowing of motoneurone firing rates in fatigue of human voluntary contractions. J Physiol 1986; 379: 451-459
• 14 Carpentier A, Duchateau J, Hainaut K. Motor unit behaviour and contractile changes during fatigue in the human first dorsal interosseus. J Physiol 2001; 534: 903-912
• 15 Enoka RM, Robinson GA, Kossev AR. Task and fatigue effects on low-threshold motor units in human hand muscle. J Neurophysiol 1989; 62: 1344-1359
• 16 Garland SJ, Enoka RM, Serrano LP, Robinson GA. Behavior of motor units in human biceps brachii during a submaximal fatiguing contraction. J Appl Physiol (1985) 1994; 76: 2411-2419
• 17 Harriss DJ, Macsween A, Atkinson G. Standards for ethics in sport and exercise science research: 2018 Update. Int J Sports Med 2017; 38: 1126-1131
• 18 Fatela P, Reis JF, Mendonca GV, Avela J, Mil-Homens P. Acute effects of exercise under different levels of blood-flow restriction on muscle activation and fatigue. Eur J Appl Physiol 2016; 116: 985-995
• 19 Loenneke JP, Abe T. Does blood flow restricted exercise result in prolonged torque decrements and muscle damage?. Eur J Appl Physiol 2012; 112: 3445-3446 author reply 3447–3449
• 20 Yasuda T, Brechue WF, Fujita T, Sato Y, Abe T. Muscle activation during low-intensity muscle contractions with varying levels of external limb compression. J Sports Sci Med 2008; 7: 467-474
• 21 Yasuda T, Brechue WF, Fujita T, Shirakawa J, Sato Y, Abe T. Muscle activation during low-intensity muscle contractions with restricted blood flow. J Sports Sci 2009; 27: 479-489
• 22 Yasuda T, Ogasawara R, Sakamaki M, Ozaki H, Sato Y, Abe T. Combined effects of low-intensity blood flow restriction training and high-intensity resistance training on muscle strength and size. Eur J Appl Physiol 2011; 111: 2525-2533
• 23 De Luca CJ, Contessa P. Hierarchical control of motor units in voluntary contractions. J Neurophysiol 2012; 107: 178-195
• 24 Krustrup P, Soderlund K, Relu MU, Ferguson RA, Bangsbo J. Heterogeneous recruitment of quadriceps muscle portions and fibre types during moderate intensity knee-extensor exercise: Effect of thigh occlusion. Scand J Med Sci Sports 2009; 19: 576-584
• 25 Meyers R. Does blood flow restriction enhance hypertrophic signaling in skeletal muscle?. J Appl Physiol (1985) 2006; 100: 1443-1444
• 26 Yasuda T, Abe T, Sato Y, Midorikawa T, Kearns C, Inoue K, Ryushi T, Muscle NI. fiber cross-sectional area is increased after two weeks of twice-daily KAATSU resistance training. Int J KAATSU Training Res 2005; 1: 65-70
• 27 Holobar A, Farina D, Gazzoni M, Merletti R, Zazula D. Estimating motor unit discharge patterns from high-density surface electromyogram. Clin Neurophysiol 2009; 120: 551-562
• 28 Cook SB, Clark BC, Ploutz-Snyder LL. Effects of exercise load and blood-flow restriction on skeletal muscle function. Med Sci Sports Exerc 2007; 39: 1708-1713
• 29 Loenneke JP, Kim D, Fahs CA, Thiebaud RS, Abe T, Larson RD, Bemben DA, Bemben MG. Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation. Muscle Nerve 2015; 51: 713-721
• 30 Loenneke JP, Fahs CA, Thiebaud RS, Rossow LM, Abe T, Ye X, Kim D, Bemben MG. The acute muscle swelling effects of blood flow restriction. Acta Physiol Hung 2012; 99: 400-410
• 31 Loenneke JP, Fahs CA, Rossow LM, Abe T, Bemben MG. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Med Hypotheses 2012; 78: 151-154
• 32 De Luca CJ, Erim Z. Common drive of motor units in regulation of muscle force. Trends Neurosci 1994; 17: 299-305
• 33 Nawab SH, Wotiz RP, De Luca CJ. Improved resolution of pulse superpositions in a knowledge-based system for EMG decomposition. In, Twenty-sixth International Conference of the IEEE Engineering in Medicine and Biology Society. San Francisco 2004; 69-71