The reliability and usefulness of an individualised submaximal shuttle run test in elite rugby league players

ABSTRACT

Purpose: The aim of the present study was to examine the reliability and usefulness of a proposed 4-min individualised submaximal shuttle run test (SSR_Indiv) in elite rugby league players.

Materials and methods: Twenty-two elite rugby league players competing in the National Rugby League competition (23.2 ± 3.4 years, 186.8 ± 5.4 cm, 100.2 ± 8.5 kg) performed the SSR_Indiv twice, seven days apart (test–retest design). The SSR_Indiv was prescribed as 75% of the average speed during a 1500-m time trial. Exercise heart rate was calculated as the average heart rate (HR) over the final 30 s (HRex). Seated HR recovery (HRR) was recorded at 1- (HRR₆₀) and 2-min (HRR₁₂₀) post-exercise. Data were analysed with magnitude-based inferences.

Results: Test–retest typical errors were moderate for HRex (1.2 percentage points; 90% confidence limits: 1.0–1.7), HRR₆₀ (3.4; 2.7–4.6) and HRR₁₂₀ (2.9; 2.3–3.9). Intraclass correlation coefficients were extremely high for HRex (0.91; 0.78–0.94) and very high for both HRR₆₀ (0.80; 0.61–0.90) and HRR₁₂₀ (0.84; 0.69–0.92). Thresholds for an individual change that would be likely small and greater than the typical error were ±1.8 (percentage points), ±4.6 and ±4.1 for HRex, HRR₆₀ and HRR₁₂₀, respectively.

Conclusions: The SSR_Indiv demonstrates acceptable reliability in the assessment of HRex and HRR, thus demonstrating its potential usefulness for monitoring fitness and fatigue in elite rugby league players.

KEYWORDS:

• Submaximal heart rate
• heart rate recovery
• fitness monitoring
• individual responses

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

No external financial support was received for this study.