Intensity Thresholds and Maximal Lactate Steady State in Small Muscle Group Exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Biochemistry

Background:

• Lactate turn points (LTPs) and ventilatory turn points (VTs) are key indicators of exercise intensity.
• The applicability of these markers in small muscle group exercises requires further investigation.

Purpose of the Study:

• To determine the first (LTP1) and second (LTP2) lactate turn points during incremental bicep curl exercise.
• To verify these LTPs against ventilatory turn points (VT1 and VT2) and constant-load exercise tests.
• To assess the validity of the three-phase exercise model for small muscle groups.

Main Methods:

• Twelve subjects performed a one-arm incremental bicep curl test (IET) to determine LTPs.
• Spirometric data was used to identify VT1 and VT2.
• Constant-load (CL) exercise tests were conducted below and above identified turn points to verify lactate steady-state.

Main Results:

• LTP1 was identified at 1.9 ± 0.6 kg and LTP2 at 3.8 ± 0.7 kg during the IET.
• LTP1 and LTP2 values were not significantly different from VT1 and VT2.
• Constant-load tests demonstrated a lactate steady-state below LTP2, validating the three-phase model for small muscle groups.

Conclusions:

• The three-phase exercise model, characterized by LTPs and VTs, is applicable to small muscle group exercises like the bicep curl.
• Incremental bicep curl tests can reliably determine LTPs, which correlate with ventilatory thresholds.
• Further research should explore the physiological responses across different exercise modalities and muscle groups.