PMID 37754606

Research
All papers

Muscular Adaptations to Concurrent Resistance Training and High-Intensity Interval Training in Adults with Type 2 Diabetes: A Pilot Study

Orlando G, Pugh J, Faulkner S, Balducci S, Sacchetti M, Pugliese G, Bazzucchi I, Haxhi J, Martinez-Valdes E, Falla D, Manolopoulos K, Nimmo MA

Question

Does adding HIIT after resistance training improve or interfere with muscle performance, muscle size, and muscle quality adaptations in adults with type 2 diabetes?

Summary

In sedentary men with uncomplicated type 2 diabetes, eight weeks of supervised resistance training plus cycling HIIT improved VO2max, quadriceps volume, knee power, and some strength outcomes. Compared with resistance training alone, adding HIIT produced larger VO2max gains but smaller improvements in lower-limb muscle quality.

Methodology

  • Sedentary overweight/obese men with uncomplicated type 2 diabetes
  • 12 participants.
  • Resistance training plus cycle ergometer.
  • Work intervals: 1-min cycling at workload designed to elicit 90% HRmax.
  • Recovery: 1-min low-intensity cycling at 30-40% HRmax.
  • Intensity: 90% HRmax target.
  • 75 min total, 25 min HIIT portion.
  • 3 sessions/week.
  • 8 weeks.
  • Open-label parallel randomized clinical trial pilot analysis
  • VO2max, Muscle strength, Muscle power, and Muscle volume were tracked.

Outcomes

VO2max

Both groups improved VO2max, with larger gains in RT+HIIT.

RT +12%, p=0.034; RT+HIIT +27%, p<0.001; between-group change p=0.023.

Improved

Muscle volume

Quadriceps volume increased in both groups.

RT +5.9%, p=0.035; RT+HIIT +6%, p=0.004.

Improved

Strength

RT improved multiple 1RM tests; RT+HIIT significantly improved lat pulldown but not all lower-body 1RM outcomes.

RT leg extension p=0.021, step-up p<0.001, lat pulldown p=0.005, chest press p=0.041; RT+HIIT lat pulldown p=0.003.

Mixed

Muscle quality

Lower-limb muscle-quality improvements were smaller with RT+HIIT than RT alone.

Between-group leg step-up p=0.035; leg extension p=0.015.

Safety concern

Glycaemia

Body composition, HbA1c, and fasting glucose did not change in either group.

No clear change

Insights

  • Adding HIIT after RT can increase fitness but may reduce the relative muscle-quality benefit of RT alone.
  • For T2DM, screen carefully and supervise progression.

Limitations

  • Very small pilot sample
  • Male-only early-stage T2DM
  • Baseline group imbalance
  • Diet not controlled
  • RT+HIIT had higher total exercise volume than RT

Safety

  • No exercise-related adverse events, including hypoglycaemia, were reported.