PMID 31671584

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High-Intensity Interval Circuit Training Versus Moderate-Intensity Continuous Training on Functional Ability and Body Mass Index in Middle-Aged and Older Women: A Randomized Controlled Trial

Ballesta-García I, Martínez-González-Moro I, Rubio-Arias JÁ, Carrasco-Poyatos M

Question

To determine whether high-intensity interval circuit training or moderate-intensity continuous training induces greater adaptations in functional ability and BMI in middle-aged and older women.

Summary

This randomized controlled trial compared high-intensity interval circuit training, moderate-intensity continuous circuit training, and a non-exercise control group in independent middle-aged and older women. Both exercise groups trained twice weekly for 18 weeks. HIICT improved upper-limb strength more than MICT and control, and HIICT improved BMI compared with control. Both HIICT and MICT improved lower-limb strength, gait/dynamic balance, and 6-minute walk performance compared with control. Five adverse events occurred in the MICT and control groups and did not occur during exercise classes.

Methodology

  • Independent middle-aged and older women from elderly day care centres in Murcia, Spain.
  • 54 participants.
  • Functional circuit training using lower- and upper-limb movements with bodyweight and external load progressions.
  • Work intervals: 1-1.5 min.
  • Recovery: 2-2.5 min.
  • Intensity: RPE 14-18 overall; work intervals progressed from 14-15 to 16-18 on Borg 6-20 scale.
  • 1 hour per session; HIICT exercise volume 18-40 min depending on mesocycle.
  • 2 sessions per week.
  • 18 weeks.
  • 18-week quasi-experimental randomized controlled trial with HIICT, MICT, and non-exercise control groups
  • Upper limb strength, Lower limb strength, Gait and dynamic balance, and Cardiorespiratory fitness were tracked.

Outcomes

Arm curl test

A significant training x group interaction was found; HIICT was statistically better than MICT and control. Increment means were CG 1.8 reps, MICT -0.5 reps, and HIICT 2.8 reps.

Training x group F=8.1, p=8.99e-4, eta2=0.192; HIICT better than MICT by 6.6 reps and CG by 9.3 reps in reported pairwise contrasts.

Improved

30-second sit-to-stand

Both HIICT and MICT were statistically better than control for lower-limb strength. Increment means were CG -1.9 reps, MICT 3.8 reps, and HIICT 5.6 reps.

Training x group F=17.42, p=1.81e-6, eta2=0.381; HIICT better than CG by 5.6 reps and MICT better than CG by 3.2 reps.

Improved

Timed up and go

Both HIICT and MICT were statistically better than control for gait/dynamic balance. Increment means were CG 0.36 s, MICT -0.87 s, and HIICT -0.78 s.

Training x group F=11.41, p=8.30e-5, eta2=0.281; HIICT better than CG by -0.78 s and MICT better than CG by -0.23 s.

Improved

6-minute walk test

Both HIICT and MICT were statistically better than control for 6MWT distance. Increment means were CG -16 m, MICT 43 m, and HIICT 36 m.

Training x group F=9.34, p=3.57e-4, eta2=0.256; HIICT better than CG by 43 m and MICT better than CG by 55 m in reported pairwise contrasts.

Improved

BMI

HIICT was statistically better than control for BMI. Increment means were CG +0.3 kg/m2, MICT -0.1 kg/m2, and HIICT -0.3 kg/m2.

Training x group F=6.99, p=0.002, eta2=0.215; HIICT better than CG by -1.4 kg/m2.

Improved

Adverse events

Five adverse events were registered in MICT and control groups, causing loss to follow-up; none occurred during exercise classes.

Mixed

Insights

  • For independent older women, HIICT can be structured as progressive functional circuits with RPE-guided work intervals rather than all-out efforts.
  • Moderate continuous circuit training improved several functional outcomes similarly to HIICT, so HIICT superiority should not be generalized across all functional domains.
  • A two-week familiarization period and RPE education may be useful before higher-intensity circuits in older adults.
  • Bodyweight and functional-movement circuits are more directly adaptable to app workouts than bike- or lab-based HIIT, but this study's sessions were long and supervised.

Limitations

  • Participants and instructors could not be blinded
  • Final analyzed sample was 41 of 54 randomized participants
  • Population limited to independent middle-aged and older women
  • No long-term follow-up
  • Warm-up and cool-down durations were not specified
  • Achieved session RPE distributions were not reported

Safety

  • Four women in MICT and one in control were lost to follow-up due to eye surgery, foot surgery, clavicle fracture, and two hip fractures after a fall.
  • The article states these adverse events did not occur during exercise classes.
  • No HIICT exercise-class adverse event was reported in the the paper.