Effect of a four-week detraining period on secondary school students' cardiorespiratory fitness: a cluster-randomized controlled trial

BACKGROUND: The aim of the present study was to examine the effect of a four-week detraining period after a short-term physical fitness program on secondary school students’ cardiorespiratory fitness levels in the Physical Education setting.METHODS: Eighty-two secondary students (33 males and 49 females; mean age 13.7±0.8 years) were cluster-randomly assigned into control group (N.=36) or experimental group (N.=40). The experimental group students performed a physical fitness program twice a week for nine weeks. Students’ cardiorespiratory fitness was measured by the 20-meter shuttle run test at the beginning and at the end of the physical fitness program, and after the four-week detraining period.RESULTS: The multilevel linear model showed that the experimental group students improved their cardiorespiratory fitness levels after the physical fitness program (P<0.05; d=0.19). However, students’ cardiorespiratory fitness values reverted back to the baseline after the detraining period (P>0.05).CONCLUSIONS: Although in the physical education setting a short-term physical fitness program increased the students’ cardiorespiratory fitness levels, after a four-week detraining period students’ levels reverted back to the baseline. Physical education teachers should apply maintenance programs or plan longer physical fitness programs with an intermittent program (15 intense minutes every session) along the scholar year to maintain students’ cardiorespiratory fitness levels.