PMID 37755863

Research
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Comparison of Ultra-Short Race Pace and High-Intensity Interval Training in Age Group Competitive Swimmers

Papadimitriou K, Kabasakalis A, Papadopoulos A, Mavridis G, Tsalis G

Question

To examine acute responses of an ultra-short race pace training set on kinematic characteristics, biomarkers, heart rate, and perceived exertion and compare them with a HIIT set, both oriented to the 100 m freestyle event, in national-level adolescent swimmers.

Summary

This acute swimming study compared two high-intensity pool sets in the same 18 national-level adolescent swimmers. Ultra-short race pace training used 20 x 25 m front crawl at 100 m race pace with 35-second intervals, while the HIIT set used 5 x 50 m front crawl at maximal intensity with 3-minute intervals. USRPT produced faster swimming velocity but lower distance per stroke and stroke index, and it produced lower blood lactate, blood glucose, heart rate, and perceived exertion than the HIIT protocol.

Methodology

  • Eighteen healthy national-level adolescent competitive swimmers, 8 boys and 10 girls, aged 13.5 +/- 0.1 years.
  • 18 participants.
  • Front crawl swimming.
  • Work intervals: 25 m at 100 m pace, about 17 s in the example.
  • Recovery: 35 s between repetitions; 2 min between the two 10-repetition parts.
  • Intensity: Approximately 100% of 100 m best-performance pace.
  • Core set duration not reported as a single total; includes 500 m of work with 35-s intervals and a 2-min mid-set rest.
  • Single acute test.
  • Acute.
  • Randomized counterbalanced acute within-subject comparison of two swimming test protocols on separate days.
  • Swimming velocity, Distance per stroke, stroke rate, and stroke index, Blood lactate, and Blood glucose were tracked.

Outcomes

Swimming velocity

Swimming velocity was higher during USRPT1 and USRPT2 than HIIT: 1.61 +/- 0.20 and 1.60 +/- 0.20 vs 1.56 +/- 0.20 m/s.

p < 0.001; eta2 = 0.70

Improved

Distance per stroke

Distance per stroke was lower during USRPT1 and USRPT2 than HIIT: 1.41 +/- 0.81 and 1.46 +/- 0.23 vs 1.63 +/- 0.37 m.

p = 0.007 and p < 0.001; eta2 = 0.20

Safety concern

Stroke index

Stroke index was lower during USRPT1 and USRPT2 than HIIT: 1.82 +/- 0.70 and 1.78 +/- 0.71 vs 2.26 +/- 0.82 m2/s.

p < 0.001 for both; eta2 = 0.60

Safety concern

Blood lactate

Maximal blood lactate was lower after USRPT1 and USRPT2 than HIIT: 8.7 +/- 0.8 and 10.0 +/- 0.9 vs 12.9 +/- 0.4 mmol/L.

p < 0.001 and p = 0.001; eta2 = 0.90

Improved

Heart rate

Heart rate was lower after USRPT1 and USRPT2 than HIIT: 173 +/- 1 and 180 +/- 0 vs 196 +/- 1 bpm.

p < 0.001; eta2 = 0.90

Improved

RPE

RPE was lower after USRPT1 than HIIT, but full USRPT2 reached the same reported RPE value as HIIT.

USRPT1 vs HIIT: 7 +/- 0 vs 8 +/- 0, p = 0.015, eta2 = 0.30

Mixed

Insights

  • In trained adolescent swimmers, shorter race-pace 25 m repeats can produce lower acute physiological load than longer maximal 50 m repeats.
  • Interval structure changes the balance between speed, lactate, heart rate, perceived exertion, and efficiency metrics.
  • USRPT evidence from this paper is best treated as sport-specific acute performance evidence, not general consumer HIIT evidence.

Limitations

  • Small sample
  • Acute-only comparison
  • No long-term performance or adaptation outcomes
  • Specialized athlete population
  • Swimming-specific protocol and equipment
  • No explicit adverse event reporting beyond safety procedures

Safety

  • Safety and adherence details were not reported in the paper.