Masters Degrees (Exercise, Sport and Lifestyle Medicine)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/105284

Browse

Browsing Masters Degrees (Exercise, Sport and Lifestyle Medicine) by browse.metadata.advisor "Engelbrecht, Louise"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Functional thresholds and its association with 20- and 40 km cycling performance
    (Stellenbosch : Stellenbosch University, 2022-12) Brandt, Rieta-Marie; Terblanche, Elmarie; Engelbrecht, Louise; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Exercise, Sport and Lifestyle Medicine.
    ENGLISH ABSTRACT: Threshold Power (FTP) and Critical Power (CP) are both functional thresholds that potentially are more comprehensive measures of an athlete’s cycling endurance performance capabilities compared with metabolic (lactate) thresholds, which are limited to the functioning of a single metabolic parameter. The functional thresholds are based on the measurement of mechanical work (i.e., power output) and exercise tolerance and are also readily accessible to coaches and athletes of all levels. The purpose of this study was to examine the association of CP and FTP with cycling time trial performance in a laboratory setting. §Thirteen trained to well-trained MTB riders, including men (n = 8) and women (n = 5), aged between 19 and 51 years, participated in this study. The cycling tests included a ramp incremental test to exhaustion, a 3-min all-out test, a 20-min FTP test, a 20 km (TT2) and 40 km (TT40) time trial. Inferential statistical analysis was done to examine the relationships between CP, FTP, peak power output (PPO), VO2max, TT20 and TT40. Significant correlations were observed between CP, FTP, PPO and VO2max (r = 0.58 to 0.97, p < 0.05), but not between absolute CP and VO2max (r = 0.40, p > 0.05). PPO (338 ± 74 W, 4.7 ± 0.6 W·kg-1), CP (291 ± 78 W, 4.0 ± 0.7 W·kg-1) and FTP (230 ± 63 W, 3.2 ± 0.6 W·kg-1) were significantly correlated to TT20 and TT40 performance times (r = 0.75 to 0.97, p < 0.001). Absolute FTP was more strongly correlated to TT20 and TT40 than CP (r = 0.97 and 0.89 vs. r = 0.75 and 0.78, p < 0.001). Even though the power outputs at FTP and CP were significantly correlated (r = 0.90 to 0.96, p < 0.001), the moderate to low ICC scores (relative: 0.21 and absolute: 0.68), suggests that these two thresholds should not be used interchangeably. The absolute PPO was significantly higher than the power outputs at CP and FTP, while no significant difference was observed between the power outputs at CP and FTP. The relative power outputs were significant different between the power outputs at CP and FTP, but not between PPO and CP. The calculated effect sizes between both relative and absolute measures (ES = 0.61 and 0.38, respectively) suggest that the differences between the power outputs are practically meaningful, even though they were not statistically significantly different. It was concluded that both functional thresholds, CP and FTP (absolute and relative measures), are valid and valuable measures of cycling endurance performance for 20 km and 40 km distances. Of the two thresholds, absolute FTP had the strongest association with cycling time trial performance in a laboratory setting.