Repeated-Sprint Ability (RSA) — Part I: Factors Contributing to Fatigue
Key Findings (abstract)
Definition: short sprints (<10 s) with brief recoveries (<60 s) are common in team and racket sports; the ability to recover and reproduce performance in subsequent sprints = repeated-sprint ability (RSA)
How fatigue shows: a decline in maximal/mean sprint speed (running) or in peak power/total work (cycling) across repetitions; performance decrements are inversely correlated with initial sprint performance (the faster the first sprint, the bigger the drop)
Task dependency: the work/recovery structure changes the time course and magnitude of fatigue — and probably the contribution of each mechanism
Muscle level: the factors that emerge as key are limited energy supply — from oxidative metabolism, anaerobic glycolysis AND phosphocreatine hydrolysis — and the build-up inside the muscle of metabolic by-products like hydrogen ions
Neural level (surface EMG): fatigue is also associated with incomplete activation of the working muscles and/or shifts in how muscles are recruited relative to one another
Pending confirmation: stiffness regulation, hypoglycaemia, muscle damage and hostile environments (heat, hypoxia) are also likely to compromise fatigue resistance
Part II (companion review, DOI in the head) covers the training interventions
Practical Application
Narrative review of repeated-sprint fatigue: over sprints of <10 s with <60 s rest, performance falls through limits on PCr, glycolytic and oxidative energy supply plus H⁺ accumulation, with reduced neural activation on top; the drop is largest in athletes with the best first sprint. For a masters athlete the message is that repeated efforts are limited by energy resupply between them — a recovery problem, not only a power problem
Aerobic (oxidative) supply is one of the three energy limits the abstract names. Inference, not tested here: a better aerobic base supports recovery between efforts; the quantitative link (VO2max ↔ PCr resynthesis) is in the full text and in Part II, not in this abstract
Buffering aids — beta-alanine (REF-351), bicarbonate (REF-354) — target the H⁺ accumulation the review names. Not from this paper; the base's own practice
Intervals with incomplete recovery train RSA. Not from this paper; the base's own practice (Part II)
Limitations
Narrative review; RSA protocols are heterogeneous (number of sprints, rest, length) — the review itself notes task dependency
Team sports have a technical-tactical component beyond physiology
No numbers in the abstract beyond the sprint/recovery definitions
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A: narrative review without systematic method (leading RSA research group)
Content correction 2026-09-27
"PCr resynthesis is aerobically dependent — better aerobics → faster PCr recovery", "aerobic fitness determines recovery, not the single sprint", "impaired excitation-contraction coupling" -> not in this abstract; removed or labelled as inference
Added the abstract's content: <10 s / <60 s definition, decrement inversely correlated with first-sprint performance, task dependency, the three energy-supply limits, EMG/neural factors, pending factors
Level A -> B+ (narrative review); Sport line "team-sport, strength, sprint" -> "team-sport, running, cycling"