PMID 33551944

Research
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HIIT Models in Addition to Training Load and Heart Rate Variability Are Related With Physiological and Performance Adaptations After 10-Weeks of Training in Young Futsal Players

Campos FS, Borszcz FK, Flores LJF, Barazetti LK, Teixeira AS, Hartmann Nunes RF, Guglielmo LGA

Question

How do two shuttle HIIT models added to regular futsal training relate to physiological, autonomic, and performance adaptations over 10 weeks?

Summary

In a small group of under-20 male futsal players, two once-weekly shuttle HIIT models added to regular team training improved aerobic and performance markers. The 86% FIET-speed model appeared more favorable for several running and jump outcomes.

Methodology

  • Under-20 first division male futsal players from Parana, Brazil.
  • 11 participants.
  • shuttle running.
  • Work intervals: 15 s running efforts inside 4 min bouts.
  • Recovery: 15 s passive rest within bouts; 3 min passive rest between sets.
  • Intensity: 86% peak speed from FIET.
  • 16 min set time plus 9 min between-set recovery.
  • once weekly.
  • 8 HIIT sessions across weeks 2-9 of a 10-week period.
  • parallel two-group longitudinal training study within a team season
  • Aerobic performance, Repeated sprint ability, Jump and sprint performance, and Heart-rate variability were tracked.

Outcomes

Aerobic fitness

Both models improved VO2peak and treadmill peak speed; HIIT86 was clearer for threshold measures.

HIIT86 had clear improvements in VO2peak, PS_TREADMILL, VT2, and VT1; HIIT100 clearly improved VO2peak and PS_TREADMILL

Improved

RSA and jumps

Both models showed benefits, with HIIT86 more favorable for RSA_best and squat jump.

HIIT86 more favorable for RSA_best and SJ with >96% probability; discussion reported HIIT86 RSA_best -3.5% and SJ +13.7%

Mixed

HRV

Heart-rate variability improved in both groups without clear superiority.

Both groups improved with >98.1% probability

Improved

Insights

  • For court-sport athletes, shuttle HIIT can manipulate total hard-running time and change-of-direction load even with the same 15 s effort unit.
  • Lower relative speed with more volume may support broader aerobic and neuromuscular adaptations than a shorter 100% FIET model.
  • The results are not a stand-alone HIIT prescription for general users because HIIT was embedded in 105 team sessions.

Limitations

  • Very small sample from one male youth team.
  • Randomization was not clearly reported.
  • No objective external load measures.
  • HRV was measured on a single pre/post day.
  • Concurrent team training and matches limit attribution.

Safety

  • No injuries were reported; inclusion required no injuries and at least 75% attendance.