Skeletal muscle mass in female athletes: The average and the extremes

Abstract

Objectives To examine the absolute and relative skeletal muscle mass (SM) in female athletes and to discuss the potential upper limit of whole‐body muscle mass between large sized female and male athletes. Methods Forty‐five female athletes and forty‐five recreationally active females (control) had muscle thickness measured by ultrasound at nine sites on the anterior and posterior aspects of the body. SM was estimated from an ultrasound‐derived prediction equation. Body fat percentage and fat‐free mass (FFM) were calculated from ultrasound measured subcutaneous fat thickness. To eliminate fat‐free component of adipose tissue (FFAT), we calculated FFM minus FFAT (FFM‐FFAT). Results FFM, FFM‐FFAT, and muscle mass were markedly higher in athletes. Fat Mass was similar (Athlete: 14.9 kg vs Control: 12.9 kg [median value]). The large‐sized female athletes had approximately 9 to 11 kg FFAT which corresponds to about 10% to 15% of FFM. Seven of the female athletes had more than 60 kg of FFM‐FFAT, the largest of whom had 77.0 kg of FFM‐FFAT. SM increased in a parabolic fashion reaching a value of 35 kg SM beyond 100 kg body mass. Only one of the athletes had a SM index of more than 13 kg/m2. Conclusions Female athletes had much greater muscle mass than controls. In large‐sized female athletes, the influence of FFAT needs to be considered when interpreting their FFM. In addition, the largest SM index in female athletes was 13.2 kg/m2, which was approximately 77% of that observed with the largest male athlete ever recorded. This difference appears similar to that observed in nonathletes.

Influence of sex and resistance training status on orofacial muscle strength and morphology in healthy adults between the ages of 18 and 40: A cross‐sectional study

“…For example, a cross‐sectional study reported approximately 75% greater whole‐body (ie, trunk plus four limbs) muscle mass when compared between resistance‐trained male athletes and recreationally active males (Abe et al, 2018). This difference was also evident when comparing resistance‐trained female athletes and recreationally active females (Abe et al, 2020). Similarly, muscular strength as determined by single joint (ie, elbow extension, knee extension, and ankle plantarflexion) tasks and multi‐joint (ie, squat and bench press) tasks was ~82% higher in resistance‐trained males than untrained males (Sale & MacDougall, 1984; Shimano et al, 2006).…”

Skeletal muscle size distribution in large‐sized male and female athletes

“…Muscle thickness (MT) and subcutaneous adipose tissue thickness (SAT) were measured by B‐mode ultrasound (Logiq e, GE, Firfield, CT and SSD‐500, Aloka, Tokyo, Japan) at nine sites on the right side of the body as described previously (Abe, Buckner, Dankel, et al, 2018; Abe, Wong, et al, 2020). This measurement was carried out at least 24 hours after the last their training session.…”

“…This is mainly due to the fat‐free component of adipose tissue being included in the measurement of FFM when estimated by underwater weighing methods. The large‐sized (>100 kg body mass) female athletes had approximately 10 kg fat‐free adipose tissue (50‐60 kg fat mass), which corresponds to about 10% to 15% of FFM (Abe, Wong, et al, 2020). It is desirable to eliminate the influence of the fat‐free component of adipose tissue to remove these effects from FFM or is desirable to estimate SM of the body in athletes.…”

“…Recent projects from our lab (Abe, Buckner, Dankel, et al, 2018; Abe, Buckner, Mattocks, et al, 2018; Abe, Wong, et al, 2020) estimated total SM in large‐sized athletes and found that four of the female athletes had more than 30 kg SM. In addition, eight of the male athletes had more than 50 kg SM.…”

Why is low body fat rarely seen in large‐sized male athletes?

“…Notably, a study reported that there was an inverse correlation ( r = −0.449) between body fat percentage and functional movement screen scores among college football players (Nicolozakes, Schneider, Roewer, Borchers, & Hewett, 2018). Further, there were inverse correlations between the percentage of body fat and high‐speed movement performance in sprint and distance running (Abe et al, 2020; Alvero‐Cruz et al, 2019; Herrmann et al, 2019), cycling (Schabort, Killian, St Clair Gibson, Hawley, & Noakes, 2000) and soccer matches (Radziminski, Szwarc, Padron‐Cabo, & Jastrzebski, 2019).…”