The Effect of Using Different Exhaustion Intervals and Mathematical Models on Critical Power Estimations

Öz

Predicted critical power (CP) varies up to 5-20% depending on the preferred mathematical model and different time to exhaustion intervals. Those differentiation rates related to CP estimations cause some contradictory results. The aim of this study was to evaluate the relationship between CP predictions obtained from three different exhaustion approaches (short: 2-10 minutes; medium: 2-15 minutes; long: 2-20 minutes) using five mathematical models (linear total work (CP1), linear 1/time (CP2), nonlinear 2-parameter (CP3), nonlinear 3-parameter (CP4) and exponential (CP5)), and other indices such as maximal lactate steady-state (MLSS), ventilatory threshold (VT), respiratory compensation point (RCP) and critical threshold (CT). 10 well trained male cyclists voluntarily participated in the study. VT and RCP levels of the athletes were determined by incremental ramp tests. Constant work rate exercises were applied on different days to determine maximal oxygen uptake, peak power output, MLSS, CT and CP. Obtained data were tested by validity analysis. As mathematical models and exhaustion intervals changed, the CP predictions varied up to 20%. Except the CP4, other CP estimations were higher than the work rates corresponding to the MLSS and VT (p<0.05). The CP5, which was estimated by short exhaustion interval, corresponded to the work rates belonging to the CT and RCP (p>0.05; standard error of estimate ~4% and r>0.95). Regardless of the preferred exhaustion interval, CP predictions obtained from the other mathematical models were insufficient to estimate any of anaerobic threshold indices (p<0.05). As a result, the CP5 estimated by short exhaustion interval can be used to predict the work rates corresponded to the CT and RCP. It was not appropriate to estimate the other threshold intensities by the CP. 

Anahtar Kelimeler

• Critical threshold
• critical power
• maximal lactate steady state
• respiratory compensation point
• ventilatory threshold

Farklı Tükenme Aralıkları ve Matematiksel Model Kullanımının Kritik Güç Tahminlerine Etkisi

Öz

Tahmin edilen kritik güç (KG) düzeyi, tercih edilen matematiksel model ve farklı tükenme zaman aralıklarına bağlı olarak %5-20 oranında farklılaşır. Bu oranlarda farklılaşan tahminler, KG ile ilişkili bir takım çelişkili sonuçlar yaratır. Bu çalışmanın amacı üç farklı tükenme aralığı (kısa: 2-10 dakika; orta: 2-15 dakika; uzun: 2-20 dakika) kullanılarak, her bir aralık için beş farklı matematiksel model (doğrusal toplam iş (KG1), doğrusal 1/zaman (KG2), doğrusal olmayan 2-parametreli (KG3), doğrusal olmayan 3-parametreli (KG4), ve üstel (KG5)), yoluyla elde edilen KG tahminlerinden hangisi ya da hangilerinin maksimal laktat dengesi (MLD), ventilasyon eşiği (VE), solunumsal kompanzasyon noktası (SKN) ve/veya kritik eşikle (KE) ilişkili olduğunu değerlendirmektir. Çalışmaya 10 iyi antrene erkek bisiklet sporcusu gönüllü olarak katılmıştır. Sporcuların VE ve SKN düzeyleri kademeli rampa testleriyle belirlenmiştir. Maksimal oksijen kullanımı, zirve güç çıktısı, MLD, KE ve KG’yi hesaplamak için farklı günlerde sabit iş oranlarında testler uygulanmıştır. Elde edilen veriler geçerlilik analizleri ile sınanmıştır. Kullanılan matematiksel model ve tükenme aralıkları değiştikçe elde edilen KG düzeyleri %20’ye kadar farklılaşmıştır. KG4 dışındaki diğer KG düzeyleri MLD ve VE’ye karşılık gelen iş oranlarından daha yüksektir (p<0,05). Kısa tükenme aralıklarıyla bulunan KG5 değeri, KE ve SKN iş oranlarına karşılık gelmiştir (p>0,05; tahmini standart hata ~%4 ve r>0,95). Tercih edilen tükenme aralığı fark etmeksizin diğer matematiksel modellerden elde edilen KG’ler herhangi bir anaerobik eşik indeksini tahmin etmede yetersizdir (p<0,05). Sonuç olarak, yalnızca kısa tükenme aralığıyla belirlenen KG5 düzeyinin, KE ve SKN iş oranlarını tahmin etmede kullanılabileceği gösterilmiştir. Diğer eşik indekslerinin KG yoluyla tahmin edilmesi uygun değildir.

Anahtar Kelimeler

• kritik eşik
• kritik güç
• maksimal laktat dengesi
• solunumsal kompenzasyon noktası
• ventilasyon eşiği

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