Evaluation of Acute Metabolic and Physiologic Responses Obtained From Sprint Interval Trainings Performed by Low Cadence/High Resistance and High Cadence/Low Resistance.

ABSTRACT As, H and Ozkaya, O. Evaluation of acute metabolic and physiologic responses obtained from sprint interval trainings performed by low cadence/high resistance and high cadence/low resistance. J Strength Cond Res XX(X): 000-000, 2025-This study aimed to compare the acute metabolic and physiologic responses obtained from different sprint interval training (SIT) protocols performed by low cadence/high resistance and high cadence/low resistance. Ten moderately trained men completed two 6 × 30-second all-out SIT protocols with 4 minutes recovery periods as follows: (a) traditional fixed-load protocol, that is, using 7.5% of body mass (BM), (traditional SIT [SITTRAD]) and (b) adjusted-load protocol, that is, using an initial load of 5% of BM and then adjusting load for subsequent bouts based on the criterion of ≥120 rpm mean cadence for the last 5 seconds of each 30-second bout, (modified SIT [SITMOD]). Gas exchange variables and blood lactate concentration ([La]) were measured before, during, and after both protocols. Total net O2 consumption and 3-hour postexercise recovery fat oxidation values were similar between SITTRAD and SITMOD (p > 0.05). However, SITMOD demonstrated a greater anaerobic contribution than SITTRAD (p < 0.001), despite similar aerobic contributions (p = 0.32). The mean cadence was significantly higher in SITMOD (139 ± 3) than that in SITTRAD (98 ± 5 rpm; p < 0.001). SITMOD elicited both the highest peak delta [La] (∆[La]) at the end of the session (19.6 ± 1.4 vs. 17.8 ± 1.8 mmol·L-1, respectively; p = 0.003) and higher ∆[La] values at the 30th, 60th, 90th, and 120th minute of recovery compared with SITTRAD (11.1 ± 1.4 vs. 8.3 ± 2.2, 4.5 ± 0.6 vs. 3.1 ± 1.1, 3.2 ± 0.8 vs. 1.9 ± 0.8, and 2.1 ± 0.9 vs. 0.7 ± 0.6 mmol·L-1, respectively; p < 0.05). In conclusion, the high-cadence/low-resistance protocol (i.e., SITMOD) resulted in a greater anaerobic contribution than the traditional fixed-load protocol that leaded low cadence/high resistance (i.e., SITTRAD).