Exercise Load Variation at Different Subjective Intensities of High-Intensity Interval Training Using Body Weight
Question
Can bodyweight HIIT exercises performed at subjective intensity levels reach a high-intensity oxygen uptake load?
Summary
In healthy young men, bodyweight squats, front lunges, and side lunges reached more than 60% of peak VO2 when participants performed them at a subjective intensity of 'somewhat hard' or 'hard'. Fast walking reached only about 60% peak VO2 at 'hard'.
Methodology
- Twenty-eight healthy male university students.
- 28 participants.
- Squat, front lunge, side lunge, fast walking, and low-intensity foot stomping.
- Work intervals: 1 min per bodyweight exercise.
- Recovery: 1 min 30 s low-intensity foot stomping.
- Intensity: Subjective intensity: fairly light, somewhat hard, or hard.
- 10 min per subjective intensity condition.
- Acute testing.
- Acute testing.
- Acute within-participant laboratory comparison of subjective intensity conditions
- Percent peak VO2, Heart rate, and Exercise frequency were tracked.
Outcomes
Squat VO2
Squats exceeded 60% peak VO2 at somewhat hard and hard intensities.
53.1 +/- 17.4%, 65.3 +/- 18.0%, and 76.6 +/- 25.3% peak VO2 for fairly light, somewhat hard, and hard
Lunge VO2
Side and front lunges exceeded 60% peak VO2 at somewhat hard and hard intensities.
Side lunge 56.1%, 70.5%, 81.8%; front lunge 55.5%, 70.5%, 80.9% peak VO2 across the three intensity levels
Fast walking VO2
Fast walking produced lower oxygen uptake than the lunge and squat exercises and reached about 60% peak VO2 only at hard intensity.
42.3 +/- 15.8%, 52.2 +/- 16.4%, and 59.1 +/- 14.5% peak VO2
Subjective intensity
VO2 and heart rate generally rose as subjective intensity increased.
VO2 increased with subjective intensity for squat, side lunge, front lunge, and fast walking (p<0.01), with some nonsignificant differences between somewhat hard and hard for squat and fast walking
Insights
- Subjective intensity can be a practical cue for bodyweight HIIT when external load is unavailable.
- Squats and lunges are more likely than fast walking to reach high-intensity oxygen uptake in young healthy men.
- Lower-limb joint load should be considered when prescribing repeated squat and lunge intervals.
Limitations
- Acute oxygen uptake study; no longitudinal training outcomes.
- Only young healthy male university students were studied.
- Exercise depth, tempo, and movement quality were self-adjusted rather than standardized.
- Nutrition, arteriovenous oxygen difference, and muscle activity were not controlled or measured.
Safety
- Adverse events were not reported.
- Authors cautioned that squat and lunge exercises may impose high lower-limb joint loads and joint-pain risk.