1) The study examined how body composition characteristics like body fat percentage, lean body mass, and thigh lean mass contribute to aerobic and anaerobic cycling performance as measured by critical power (CP) and anaerobic work capacity (AWC). 2) The results showed lean body mass was the best predictor of CP, while thigh lean mass was the best predictor of AWC. 3) This supports that AWC is associated with energy stores in the active muscles, so training to increase thigh lean mass could improve AWC, while total body lean mass training could boost CP.

1. CONTRIBUTIONS OF BODY COMPOSITION CHARACTERISTICS TO
AEROBIC AND ANAEROBIC CYCLING PERFORMANCE
M. Travis Byrd, Brian J. Wallace, Jody L. Clasey, Jonathan R. Switalla, Jessica Quinn,
Paul Baker, Parashar Joshi, Haley C. Bergstrom
University of Kentucky, Lexington KY
Theoretically, the critical power (CP) test provides estimates of three separate
parameters: 1) the highest power output that can be maintained for an extended period of
time without exhaustion, called the CP; 2) the total amount of work that can be performed
using the stored energy sources within the activate muscles, called the anaerobic work
capacity (AWC); and 3) the time to exhaustion at any power output greater than CP. No
previous studies, however, have examined the contribution of body composition
characteristics (body fat percent [%BF], mineral free total body lean mass [LBM], and
mineral free thigh lean mass [TLM]) to CP and AWC. PURPOSE: The purpose of this
study was to examine the ability of body composition characteristics (%BF, LBM, TLM)
to predict CP and AWC. METHODS: Fifteen, anaerobically trained males (mean ± SD
age: 22.5 ± 2.5 yrs; height: 177.5 ± 7.5 cm; body mass: 83.7 ± 12.1 kg) completed this
study. The total body (%BF and LBM) and regional (TLM) composition characteristics
of each subject were estimated by dual energy x-ray absorptiometry (DXA). The TLM
was delineated using previously published anatomical boundaries for both left and right
thighs. The CP and AWC were determined from the 3-min all-out CP test, with the
resistance set at 4.5% of the total body mass. The CP was defined as the mean power
output over the final 30s of the test and the AWC was calculated using the equation,
AWC = 150s (P150 – CP), where P150 equals the mean power output for the first 150s.
Statistical analyses included Pearson product-moment correlations and stepwise multiple
regression analyses at an alpha level of p ≤ 0.05. RESULTS: The correlations among the

2. body composition characteristics (mean ± SD: %BF = 16.1 ± 4.5 %; LBM = 67.0 ± 9.6
kg; TLM = 14.3 ± 2.6 kg) and the CP test parameters (CP = 210 ± 37W; AWC = 15.1 ±
29.3kJ) are presented in Table 1. The stepwise regression analyses indicated that only
LBM contributed significantly to the prediction of CP (CP = 2.3[LBM] + 56.7 [r2 =
0.346; SEE = 31.4W; p = 0.021]) and only TLM to AWC (AWC = 0.8[TLM] + 3.7 [r2 =
0.479; SEE = 2.2kJ; p = 0.004]). CONCLUSIONS: These findings indicated that the
aerobic component (CP) of the CP test was most closely related to total body LBM. The
anaerobic component (AWC), however, was more closely related to the mineral free lean
mass of the thigh muscles than the total body. These findings supported that during cycle
ergometry, the AWC is associated with stored energy sources within the active muscle
mass. PRACTICAL APPLICATIONS: The LBM and TLM contributed significantly
to the prediction of CP and AWC, respectively. Thus, training programs to improve CP
and AWC should be designed to include resistance-training exercises to increase mineral
free total body and thigh lean mass, respectively.
Table 1. Correlations among body composition characteristics and parameters of the
critical power (CP) test (n = 15).
AWC CP %BF LBM TLM
AWC 1.000
CP 0.311 1.000
%BF 0.365 -0.184 1.000
LBM 0.678* 0.588* -0.036 1.000
TLM 0.692* 0.538* 0.006 0.975* 1.000

3. AWC = anaerobic work capacity, CP = critical power, TLM = mineral free thigh lean mass, LBM =
mineral free total body lean mass, %BF = body fat percent.
*r significant at p ≤ 0.05