Analysis of the factors influencing the proximity and agreement between critical power and maximal lactate steady state: a systematic review and meta-analyses

Figure 1. PRISMA flow chart for new systematic reviews for study selection process. Adapted from Page et al. (2021). PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Figure 2. Summary of the quality assessment of the 10 cross-over trials. 1, Appropriate cross-over design; 2, randomized order of receiving treatment; 3, carry-over effects; 4, unbiased data; 5, allocation concealment; 6, blinding; 7, incomplete outcome data; 8, selective outcome reporting; 9, other bias.

Figure 3. Forest plot reporting mean difference (MD) and 95% confidence intervals (CI) computed as the difference in power output (W) between critical power and maximal lactate steady state. Studies: Iannetta et al., 2019; Keir et al., 2015; Caen et al., 2022; Lievens et al., 2021; Okuno et al., 2011; Iannetta et al., 2022; Maturana et al., 2016; Caritá, Greco & Denadai, 2009; Ozkaya et al., 2022.

Figure 4. Forest plot reporting mean difference (MD) and 95% confidence interval (CI) computed as the difference in .VO2 (L⋅min−1) between critical power and maximal lactate steady state. Studies: Puga et al., 2009; Keir et al., 2015; Caen et al., 2022; Okuno et al., 2011; Ozkaya et al., 2022.

Figure 5. Forest plot reporting mean difference (MD) and 95% confidence interval (CI) computed as the difference in HR (bpm) between critical power and maximal lactate steady state. Studies: Puga et al., 2009; Keir et al., 2015; Okuno et al., 2011.

Figure 6. Forest plot reporting mean difference (MD) and 95% confidence interval (CI) computed as the difference in BLC (mM) between critical power and maximal lactate steady state. Studies: Puga et al., 2009; Keir et al., 2015; Okuno et al., 2011.

Figure 7. Bubble plots showing the association between critical power (CP) and maximal lactate steady state (MLSS) mean differences (MD) and the mean CP (A) or MLSS (B) in W. The size of the points is drawn proportional to the weight that the studies received in the analysis (with larger points for studies that received more weight).

Figure 8. Analysis of the agreement between CP and MLSS. Pooled (black curve) and individual studies’ (grey dashed curve) estimated normal distributions of the differences between MLSS and CP expressed as W (A), L⋅min−1 (B), bpm (C), and mM (D). The vertical lines indicate the estimated pooled limits of agreements (solid vertical lines) and their outer 95% confidence intervals (dashed vertical lines).