Mixed

High-intensity interval training (HIIT) engages a unique subset of skeletal muscle signaling pathways and substrates compared to work- and duration-matched moderate-intensity continuous training (MICT), specifically involving kinases like PKC alpha/beta and substrates like MTFP1, which are associated with plasma lactate levels.

To trigger unique muscle adaptations associated with high-intensity training, you don't need to exercise for hours. A short session of 5 minutes of high-intensity intervals (e.g., 1-minute sprints followed by 1-minute recovery, repeated 5 times) is sufficient to activate specific signaling pathways (like PKC and MTFP1) that are not significantly engaged by moderate, continuous exercise of the same total duration and workload. This suggests HIIT is a highly time-efficient strategy for stimulating metabolic and mitochondrial adaptations.