Cardiorespiratory and Aerobic Demands of High-Rep Squats

Differences in oxygen consumption between high and low relative strength athletes during squats.

Nov 13, 2024

Fit man lying on the gym floor exhausted after high-rep squats wearing a light blue t-shirt in a dark gym with some light blue fluorescent lighting. — Image created by Author using Midjourney

This study investigates the cardiorespiratory responses during squat exercises, focusing on how these responses vary between individuals with different strength levels. The research aims to clarify the aerobic contributions of resistance training, particularly squats, which are traditionally viewed as anaerobic exercises.

Key Findings

Participants: The study involved 22 young, healthy, resistance-trained men (average age 28 years). They were split into two groups based on their one-repetition maximum (1RM) squat strength: high strength (HS) and low strength (LS).
Exercise Protocol: Participants performed five sets of squats at 65% of their 1RM for ten repetitions with three-minute rest intervals. Heart rate and oxygen consumption (V̇O₂) were continuously measured.
Oxygen Demand: The highest V̇O₂ recorded during the squat exercise reached 47.8 ml/kg/min, corresponding to about 100.6% of the participants' predetermined V̇O₂max. Notably, the HS group achieved a higher peak V̇O₂ relative to their max compared to the LS group (108.0% vs. 93.7%).
Cardiorespiratory Responses: During exercise, both V̇O₂ and carbon dioxide production (V̇CO₂) increased significantly. However, during rest intervals, V̇CO₂ remained higher than V̇O₂, indicating a unique ventilatory response during resistance training.
Strength Variations: The study found that individuals with higher relative strength exhibited greater oxygen consumption during squats, suggesting that strength training can elicit significant aerobic demands.

Key Differences in Cardiorespiratory Responses Between High and Low Strength Groups

Peak Oxygen Consumption (V̇O2): The HS group demonstrated a higher peak V̇O₂ in relation to their V̇O₂max compared to the LS group (108.0% vs. 93.7%). This indicates that individuals with higher strength levels engage in squats at intensities that elicit greater oxygen demands.
Heart Rate: The HS group had higher heart rate levels during the exercise compared to the LS group. The average heart rate across all sets was approximately 90% of the maximal heart rate in both groups, but the HS group reached higher absolute values.
Aerobic Demand: The study concluded that the higher strength levels in the HS group resulted in engaging in squat exercises at intensities that elicit greater oxygen demands. This suggests that strength training can significantly contribute to aerobic fitness in individuals with higher strength levels.

In summary, the HS group experienced a more pronounced cardiorespiratory response during the squats than the LS group, as evidenced by higher peak V̇O₂, heart rate, and overall aerobic demand. These findings highlight the potential for strength training to enhance aerobic fitness, especially in individuals with higher baseline strength levels.

Practical Takeaways

Aerobic Contribution in Resistance Training: This study highlights that resistance exercises like squats involve substantial aerobic energy contributions, challenging the traditional view that they are purely anaerobic.
Training Implications: For athletes and trainers, understanding that squats can significantly elevate heart rate and oxygen demand may influence training programs by incorporating appropriate rest intervals and intensities to optimise both strength and aerobic conditioning.
Individual Differences: Recognising that individuals with higher muscular strength may experience different cardiorespiratory responses can help tailor training programs to enhance performance and recovery based on individual fitness levels.

Overall, this research provides valuable insights into the interplay between strength training and aerobic capacity, emphasising the importance of considering both aspects in exercise programming.

Reference

Hong, S., Oh, M., Oh, C., Lee, H., Suh, S., Park, H., Lalande, S., Tanaka, H., & Jeon, J. Y. (2024). Cardiorespiratory and aerobic demands of squat exercise. Scientific Reports, 14(1), 1-9. https://doi.org/10.1038/s41598-024-68187-z