Myofibrillar protein synthesis and muscle hypertrophy individualized responses to systematically changing resistance training variables in trained young men

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.

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Correction: Acute Post-Exercise Myofibrillar Protein Synthesis Is Not Correlated with Resistance Training-Induced Muscle Hypertrophy in Young Men

PLoS ONE ◽

10.1371/journal.pone.0098731 ◽

2014 ◽

Vol 9 (5) ◽

pp. e98731

Author(s):

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Muscle Hypertrophy ◽

Young Men ◽

Myofibrillar Protein ◽

Post Exercise ◽

Myofibrillar Protein Synthesis

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Acute Post-Exercise Myofibrillar Protein Synthesis Is Not Correlated with Resistance Training-Induced Muscle Hypertrophy in Young Men

PLoS ONE ◽

10.1371/journal.pone.0089431 ◽

2014 ◽

Vol 9 (2) ◽

pp. e89431 ◽

Cited By ~ 115

Author(s):

Cameron J. Mitchell ◽

Tyler A. Churchward-Venne ◽

Gianni Parise ◽

Leeann Bellamy ◽

Steven K. Baker ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Muscle Hypertrophy ◽

Young Men ◽

Myofibrillar Protein ◽

Post Exercise ◽

Myofibrillar Protein Synthesis

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Does Muscle Hypertrophy Relate To Resistance Training-Induced Changes In Myofibrillar Protein Synthesis In Women?

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000671176.24728.6b ◽

2020 ◽

Vol 52 (7S) ◽

pp. 104-104

Author(s):

Julia M. Malowany ◽

Sidney Abou Sawan ◽

Cassidy Tinline-Goodfellow ◽

Nathan Hodson ◽

Daniel W. D. West ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Muscle Hypertrophy ◽

Myofibrillar Protein ◽

Induced Changes ◽

Myofibrillar Protein Synthesis

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Hypoenergetic diet-induced reductions in myofibrillar protein synthesis are restored with resistance training and balanced daily protein ingestion in older men

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00550.2014 ◽

2015 ◽

Vol 308 (9) ◽

pp. E734-E743 ◽

Cited By ~ 58

Author(s):

Caoileann H. Murphy ◽

Tyler A. Churchward-Venne ◽

Cameron J. Mitchell ◽

Nathan M. Kolar ◽

Amira Kassis ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Older Men ◽

Myofibrillar Protein ◽

Energy Restriction ◽

Protein Distribution ◽

Protein Meal ◽

Fed State ◽

Sarcoplasmic Protein ◽

Myofibrillar Protein Synthesis

Strategies to enhance weight loss with a high fat-to-lean ratio in overweight/obese older adults are important since lean loss could exacerbate sarcopenia. We examined how dietary protein distribution affected muscle protein synthesis during energy balance (EB), energy restriction (ER), and energy restriction plus resistance training (ER + RT). A 4-wk ER diet was provided to overweight/obese older men (66 ± 4 yr, 31 ± 5 kg/m2) who were randomized to either a balanced (BAL: 25% daily protein/meal × 4) or skewed (SKEW: 7:17:72:4% daily protein/meal; n = 10/group) pattern. Myofibrillar and sarcoplasmic protein fractional synthetic rates (FSR) were measured during a 13-h primed continuous infusion of l-[ ring-13C6]phenylalanine with BAL and SKEW pattern of protein intake in EB, after 2 wk ER, and after 2 wk ER + RT. Fed-state myofibrillar FSR was lower in ER than EB in both groups ( P < 0.001), but was greater in BAL than SKEW ( P = 0.014). In ER + RT, fed-state myofibrillar FSR increased above ER in both groups and in BAL was not different from EB ( P = 0.903). In SKEW myofibrillar FSR remained lower than EB ( P = 0.002) and lower than BAL ( P = 0.006). Fed-state sarcoplasmic protein FSR was reduced similarly in ER and ER + RT compared with EB ( P < 0.01) in both groups. During ER in overweight/obese older men a BAL consumption of protein stimulated the synthesis of muscle contractile proteins more effectively than traditional, SKEW distribution. Combining RT with a BAL protein distribution “rescued” the lower rates of myofibrillar protein synthesis during moderate ER.

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Impact of Short-term Sedentariness on Week-to-Week Myofibrillar Protein Synthesis Rates in Physically Active Young Men

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000536301.79919.83 ◽

2018 ◽

Vol 50 (5S) ◽

pp. 370

Author(s):

Brandon J. Shad ◽

Andrew M. Holwerda ◽

Yasir S. Elhassan ◽

Luc J.C. van Loon ◽

Janice L. Thompson ◽

...

Keyword(s):

Protein Synthesis ◽

Young Men ◽

Myofibrillar Protein ◽

Short Term ◽

Physically Active ◽

Myofibrillar Protein Synthesis

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Damaging eccentric exercise attenuates disuse induced declines in daily myofibrillar protein synthesis and transiently prevents muscle atrophy in healthy men.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00294.2021 ◽

2021 ◽

Author(s):

Tom S. O. Jameson ◽

Sean P Kilroe ◽

Jonathan Fulford ◽

Doaa Reda Abdelrahman ◽

Andrew John Murton ◽

...

Keyword(s):

Protein Synthesis ◽

Eccentric Exercise ◽

Vastus Lateralis ◽

Quadriceps Muscle ◽

Quadriceps Strength ◽

Myofibrillar Protein ◽

Muscle Volume ◽

Vastus Lateralis Muscle ◽

Deuterated Water ◽

Myofibrillar Protein Synthesis

Introduction: Short-term disuse leads to muscle loss driven by lowered daily myofibrillar protein synthesis (MyoPS). However, disuse commonly results from muscle damage, and its influence on muscle deconditioning during disuse is unknown. Methods: 21 males (20±1 y, BMI=24±1 kg·m-2 (±SEM)) underwent 7 days of unilateral leg immobilization immediately preceded by 300 bilateral, maximal, muscle-damaging eccentric quadriceps contractions (DAM; n=10) or no exercise (CON; n=11). Participants ingested deuterated water and underwent temporal bilateral thigh MRI scans and vastus lateralis muscle biopsies of immobilized (IMM) and non-immobilized (N-IMM) legs. Results: N-IMM quadriceps muscle volume remained unchanged throughout in both groups. IMM quadriceps muscle volume declined after 2 days by 1.7±0.5% in CON (P=0.031; and by 1.3±0.6% when corrected to N-IMM; P=0.06) but did not change in DAM, and declined equivalently in CON (by 6.4±1.1% [5.0±1.6% when corrected to N-IMM]) and DAM (by 2.6±1.8% [4.0±1.9% when corrected to N-IMM]) after 7 days. Immobilization began to decrease MyoPS compared with N-IMM in both groups after 2 days (P=0.109), albeit with higher MyoPS rates in DAM compared with CON (P=0.035). Frank suppression of MyoPS was observed between days 2-7 in CON (IMM=1.04±0.12, N-IMM=1.86±0.10%·d-1; P=0.002) but not DAM (IMM=1.49±0.29, N-IMM=1.90±0.30%·d-1; P>0.05). Declines in MyoPS and quadriceps volume after 7 days correlated positively in CON (R2=0.403; P=0.035) but negatively in DAM (R2=0.483; P=0.037). Quadriceps strength declined following immobilization in both groups, but to a greater extent in DAM. Conclusion: Prior muscle damaging eccentric exercise increases MyoPS and prevents loss of quadriceps muscle volume after 2 (but not 7) days of disuse.

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Short-term muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00360.2019 ◽

2020 ◽

Vol 318 (2) ◽

pp. E117-E130 ◽

Cited By ~ 11

Author(s):

Sean P. Kilroe ◽

Jonathan Fulford ◽

Andrew M. Holwerda ◽

Sarah R. Jackman ◽

Benjamin P. Lee ◽

...

Keyword(s):

Protein Synthesis ◽

Young Men ◽

Myofibrillar Protein ◽

Deuterated Water ◽

Short Term ◽

Muscle Disuse ◽

Before And After ◽

Mri Scans ◽

The Impact ◽

Myofibrillar Protein Synthesis

Short-term muscle disuse has been reported to lower both postabsorptive and postprandial myofibrillar protein synthesis rates. This study assessed the impact of disuse on daily myofibrillar protein synthesis rates following short-term (2 and 7 days) muscle disuse under free living conditions. Thirteen healthy young men (age: 20 ± 1 yr; BMI: 23 ± 1 kg/m−2) underwent 7 days of unilateral leg immobilization via a knee brace, with the nonimmobilized leg acting as a control. Four days before immobilization participants ingested 400 mL of 70% deuterated water, with 50-mL doses consumed daily thereafter. Upper leg bilateral MRI scans and muscle biopsies were collected before and after 2 and 7 days of immobilization to determine quadriceps volume and daily myofibrillar protein synthesis rates. Immobilization reduced quadriceps volume in the immobilized leg by 1.7 ± 0.3 and 6.7 ± 0.6% after 2 and 7 days, respectively, with no changes in the control leg. Over the 1-wk immobilization period, myofibrillar protein synthesis rates were 36 ± 4% lower in the immobilized (0.81 ± 0.04%/day) compared with the control (1.26 ± 0.04%/day) leg ( P < 0.001). Myofibrillar protein synthesis rates in the control leg did not change over time ( P = 0.775), but in the immobilized leg they were numerically lower during the 0- to 2-day period (16 ± 6%, 1.11 ± 0.09%/day, P = 0.153) and were significantly lower during the 2- to 7-day period (44 ± 5%, 0.70 ± 0.06%/day, P < 0.001) when compared with the control leg. We conclude that 1 wk of muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates in healthy young men.

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