Ratings of perceived exertion (RPE) from a submaximal 20-m shuttle-run test accurately predict children's VO2peak, but when should we stop the test?

Abstract

Purpose: The purpose of the study was to explore the validity, test-retest reliability and affective responses of a submaximal 20-m shuttle-run test (20mSRT) stopped at 6 on the Eston-Parfitt (EP) scale. The secondary aim was to examine and compare two submaximal 20mSRT protocols with different RPE end points (EP6 vs. EP7) using previously published data.

Methods: Twenty-five children (16 boys; 13.4 ± 1.0 years; 162.1 ± 8.7 cm; 49.1 ± 6.6 kg) completed three exercise tests (graded exercise test [GXT], 2 submaximal 20mSRT). The EP scale and Feeling scale were used to measure RPE and affect, respectively. The two submaximal 20mSRTs were stopped after participants reported EP6. Individual speed-RPE relationships from the submaximal 20mSRTs were linearly regressed to predict peak speed and then used to estimate VO_2peak. Previously published data (n = 25) used comparable methods, except that the participants stopped at EP7.

Results: In the EP6 protocol, a two-factor repeated measures ANOVA revealed non-significant Test and Sex main effects (p > 0.05). Reliability analysis revealed intraclass correlation coefficient of ~ 0.7 (95%CI [0.432,0.867], p < 0.001) between the submaximal 20mSRTs. Significant differences in end-test affect between the GXT and submaximal 20mSRTs were found (p < 0.001), with GXT more negative. ANOVA revealed no significant differences in end-test affect between EP6 and EP7 protocols; however, frequency count analysis revealed EP6 to result in more positive end-test affect.

Conclusion: Submaximal 20mSRT utilising RPE may offer valid predictions in VO_2peak while minimising negative affect. Test end points of EP6 and EP7 both offer valid predictions in VO_2peak. EP6 may be more beneficial in avoiding negative affect, even though a reduction in test-retest reliability was observed.

Keywords: Affect; Fitness test; Oxygen uptake; RPE.

Fig. 1

Pre-test and end-test affective responses (mean ± SE) of boys (n = 16) and girls (n = 9) performing the GXT and two submaximal 20mSRTs stopped at EP6.  =  depicts significant differences in the mean values between the two trials, * = significant differences (p < 0.001), # = significant differences (p < 0.01) Note. GXT: graded exercise test, T1: first trial of submaximal 20-m shuttle-run test, T2: second trial of submaximal 20-m shuttle-run test

Fig. 2

Percentage of participants that reported negative affective responses for the GXT and two submaximal 20mSRT trials stopped at EP6 (n = 16 boys, n = 9 girls) and EP7* (n = 14 boys, n = 11 girls). The dotted line depicts neutral affect. The range of reported negative affective responses are shown in the grey bar. Note. * Data obtained from Kasai et al. (2023)