Lean mass sparing in resistance-trained athletes during caloric restriction: the role of resistance training volume

Abstract

Many sports employ caloric restriction (CR) to reduce athletes’ body mass. During these phases, resistance training (RT) volume is often reduced to accommodate recovery demands. Since RT volume is a well-known anabolic stimulus, this review investigates whether a higher training volume helps to spare lean mass during CR. A total of 15 studies met inclusion criteria. The extracted data allowed calculation of total tonnage lifted (repetitions × sets × intensity load) or weekly sets per muscle group for only 4 of the 15 studies, with RT volume being highly dependent on the examined muscle group as well as weekly training frequency per muscle group. Studies involving high RT volume programs (≥ 10 weekly sets per muscle group) revealed low-to-no (mostly female) lean mass loss. Additionally, studies increasing RT volume during CR over time appeared to demonstrate no-to-low lean mass loss when compared to studies reducing RT volume. Since data regarding RT variables applied were incomplete in most of the included studies, evidence is insufficient to conclude that a higher RT volume is better suited to spare lean mass during CR, although data seem to favor higher volumes in female athletes during CR. Moreover, the data appear to suggest that increasing RT volume during CR over time might be more effective in ameliorating CR-induced atrophy in both male and female resistance-trained athletes when compared to studies reducing RT volume. The effects of CR on lean mass sparing seem to be mediated by training experience, pre-diet volume, and energy deficit, with, on average, women tending to spare more lean mass than men. Potential explanatory mechanisms for enhanced lean mass sparing include a preserved endocrine milieu as well as heightened anabolic signaling.

Resistance training volume does not influence lean mass preservation during energy restriction in trained males

“…In this regard, studies with a reduction in resistance training volume (and hence, lowering the mechanical loading imposed on the muscles) over time 11,12 tend to report greater lean mass losses during the course of the hypocaloric phase than studies with an increase in resistance training volume, 10,11 suggesting a link between increases in training volume over time and lean mass sparing during caloric restriction. Although this has not been directly investigated and clearly presents a gap in the literature, the hypothesis is in line with a recent review conducted by our lab 9 and in accordance with the proposed inverted U-shaped relationship between weekly training volume and hypertrophy during eucaloric conditions. 13 Possible underlying explanatory mechanisms include heightened anabolic signaling and a preserved endocrine milieu, 9 given the prerequisite of adequate diet-specific nutrition and sleep.…”

“…Although this has not been directly investigated and clearly presents a gap in the literature, the hypothesis is in line with a recent review conducted by our lab 9 and in accordance with the proposed inverted U-shaped relationship between weekly training volume and hypertrophy during eucaloric conditions. 13 Possible underlying explanatory mechanisms include heightened anabolic signaling and a preserved endocrine milieu, 9 given the prerequisite of adequate diet-specific nutrition and sleep.…”

“…Given the potential influence of sex that has been recently proposed, 9 we only included male participants in this study. Moreover, we only included lean, resistance‐trained individuals, defined as (1) at least 1 year of resistance training experience and (2) relative squat strength of at least their own body weight (1 repetition maximum).…”

“…Although it has been proposed that high‐volume resistance training is necessary to maximize anabolism in resistance‐trained individuals, 8 there is currently no consensus about the optimal amount of exercise to preserve lean mass during caloric restriction 7 . Since data from resistance‐trained athletes with detailed information regarding resistance training volume are scarce, most research conducted to date does not allow for an adequate volume quantification in total tonnage (repetitions × sets × intensity load) or weekly sets/muscle group 9 …”

“…7 Since data from resistance-trained athletes with detailed information regarding resistance training volume are scarce, most research conducted to date does not allow for an adequate volume quantification in total tonnage (repetitions × sets × intensity load) or weekly sets/muscle group. 9 Preliminary evidence suggests a potential benefit for a relatively high volume of resistance training on lean mass sparing during caloric restriction. 10 A similar trend is observed in studies that increased resistance training volume over time 11 and is supported by other research that reported lean mass losses when resistance training volume is reduced during caloric restriction.…”