Retrospective Analysis of Training Intensity Distribution Based on Race Pace Versus Physiological Benchmarks in Highly Trained Sprint Kayakers

BACKGROUND: Research results on the training intensity distribution (TID) in endurance athletes are equivocal. This non-uniformity appears to be partially founded in the different quantification methods that are implemented. So far, TID research has solely focused on sports involving the lower-body muscles as prime movers (e.g. running). Sprint kayaking imposes high demands on the upper-body endurance capacity of the athlete. As there are structural and physiological differences between upper- and lower-body musculature, TID in kayaking should be different to lower-body dominant sports. Therefore, we aimed to compare the training intensity distribution during an 8-wk macrocycle in a group of highly trained sprint kayakers employing three different methods of training intensity quantification. METHODS: Heart rate (HR) and velocity during on-water training of nine highly trained German sprint kayakers were recorded during the final 8 weeks of a competition period leading to the national championships. The fractional analysis of TID was based on three zones (Z) derived from either HR (TID(Bla-HR)) or velocity (TID(Bla-V)) based on blood lactate (B(la)) concentrations (Z1 ≤ 2.5 mmol L(−1) B(la), Z2 = 2.5–4.0 mmol L(−1) B(la), Z3 ≥ 4.0 mmol L(−1) B(la)) of an incremental test or the 1000-m race pace (TID(Race)): Z1 ≤ 85% of race pace, Z2 = 86–95% and Z3 ≥ 95%. RESULTS: TID(Bla-V) (Z1: 68%, Z2: 14%, Z3: 18%) differed from TID(Bla-HR) (Z1: 91%, Z2: 6%, Z3: 3%) in each zone (all p < 0.01). TID(Race) (Z1: 73%, Z2: 20%, Z3: 7%) differed to Z3 in TID(Bla-V) (p < 0.01) and all three TID(Bla-HR) zones (all p < 0.01). Individual analysis revealed ranges of Z1, Z2, Z3 fractions for TID(Bla-HR) of 85–98%, 2–11% and 0.1–6%. For TID(Bla-V), the individual ranges were 41–82% (Z1), 6–30% (Z2) and 8–30% (Z3) and for TID(Race) 64–81% (Z1), 14–29% (Z2) and 4–10% (Z3). CONCLUSION: The results show that the method of training intensity quantification substantially affects the fraction of TID in well-trained sprint kayakers. TID(Race) determination shows low interindividual variation compared to the physiologically based TID(Bla-HR) and TID(Bla-V). Depending on the aim of the analysis TID(Race), TID(Bla-HR) and TID(Bla-V) have advantages as well as drawbacks and may be implemented in conjunction to maximize adaptation.