text: Although the current investigation provides a detailed 
  assessment of an individual at/toward the upper limit of 
  human strength performance, it is important to appreciate 
  study limitations. First, the participant was not measured im- 
  mediately before their World’s Strongest Man championship 
  success or other landmark performances, and it is entirely pos- 
  sible the functional and structural characteristics we assessed 
  may have been even higher directly prior to peak performan- 
  ces. Despite using a wide-bore MRI scanner, due to the size of 
  the WSM’s shoulders and arms, it was not possible to scan their 
  upper body. Thus, we were not able to investigate this aspect of 
  the WSM’s muscle morphology; although given that greater hy- 
  pertrophy occurs in the upper body compared with the lower 
  body (42), it is possible that the WSM’s upper-body muscle size 
  relative to untrained controls may have been even more pro- 
  nounced than what we have documented for the lower body. 
  In the current study to provide the most representative data on 
  untrained control participants, the largest available untrained 
  control populations were used for each category of measure- 
  ments. Thus, different untrained control populations were 
  used [e.g., comparison of quadricep and hamstring size (n ¼ 
  102) vs. comparison of all the leg muscles (n ¼ 11)], which led to 
  some subtle discrepancies in the contrasts between these 
  groups and the WSM [e.g., quadriceps femoris/knee extensors, 
  þ 127% and þ 99% relative to our large pooled (n ¼ 102) and 
  smaller (n ¼ 11) untrained control samples, respectively]. 
  Importantly, however, this discrepancy does not appear to 
  meaningfully affect the interpretation of the ﬁndings. There 
  were subtle differences in the precise scanning and analysis 
  approaches used with the reference populations featured in 
  this study, including 1) magnetic ﬁeld strength [1.5 T (10, 11, 15) 
  vs. 3.0 T, WSM and (13, 14)]; 2) the interslice distance used to 
  quantify quadriceps femoris and hamstrings muscle volume 
  [1.5 cm (10, 11, 14) vs. 2.0 cm, WSM and (13)]; 3) the calculation 
  of muscle volume [area under the cubic spline ACSA-muscle 
  length curve: (10, 11, 14) vs. the equation detailed earlier: WSM 
  and (13)]; and 4) the use of unilateral MRI measures derived 
  from one limb (10, 11, 14, 15) or collapsed across two limbs 
  [WSM and (13)]. However, it seems likely that these subtle dif- 
  ferences would have had at most a very minor effect on the 
  ﬁndings. Finally, it is also important to highlight that the differ- 
  ences documented between the WSM and comparative popula- 
  tions for the various measures included in the current study 
  cannot be assumed to be anything other than a combination of 
  both innate (genetic) and environmental (training and nutri- 
  tion) factors. 