【Research Review】Latest Literature Analysis on Critical Swim Speed (CSS) Determination and Aerobic Threshold Endurance Development: A Study on Elite Athletes’ Physiological Characteristics (Article 654)

Reference Journal Source: Journal of Applied Biomechanics • International Research Findings Review Series

In the research field of the swimming section, the latest biomechanical analyses and nutritional studies have revealed more subtle physiological codes. This research report is compiled from the cutting-edge literature of the Journal of Applied Biomechanics, providing a detailed analysis of the performance of subjects in the experimental and control groups. The findings are not only highly valuable for professional coaches but also provide a scientific basis for age-group swimmers pursuing their personal best (PB).

Definition of Critical Swim Speed (CSS) in Scientific Training

Critical Swim Speed (CSS) refers to the maximum cruising pace a swimmer can sustain without excessive lactate accumulation (generally defined as the pace per 100 meters). It serves as a benchmark for scientific swim training and is highly correlated with the aerobic threshold. It is typically determined by performing all-out 400-meter and 200-meter tests and calculating the slope of time versus distance, which allows for the design of the most precise cruise interval workouts.

Muscle Engagement and Mechanical Advantages of Early Vertical Forearm (EVF)

Early Vertical Forearm (EVF) is the most propulsive-efficient catch technique in modern freestyle. This biomechanical experiment analyzed the projected arm area and shoulder joint torque of swimmers during the underwater pull phase. The results found that EVF allows swimmers to orient the forearm and palm perpendicular to the water flow direction in the first half of the stroke, significantly increasing the effective projected cross-sectional area and shifting the fulcrum of force application to the powerful latissimus dorsi and teres major muscles, greatly reducing the load on the deltoid muscles of the shoulder.

Comparative Table of Mechanical Efficiency: EVF vs. Straight-Arm Pull

Below is the compiled comparison of the experimental control group and multi-dimensional data:

Core Research Conclusions and Practical Recommendations

Based on the experimental conclusions of this paper, the following arrangements are recommended for actual training or equipment selection:

• Gastrointestinal Adaptation: During long-distance aerobic training, carbohydrate intake per hour should adapt to supplementation using the golden ratio of 2:1 glucose to fructose.
• Hydrodynamic Drag Reduction: During the underwater pull phase, focus on generating force with the EVF high elbow catch technique, shifting the fulcrum of force to the latissimus dorsi to prevent rotator cuff strain.
• Biomechanical Feedback: Strengthening the gluteus medius and deep core muscles can significantly improve pelvic tilt during the support phase, preventing uneven patellar loading under high intensity.

Common Research Q&A (FAQ)

Q: How do I calculate my own CSS pace?

A: The formula is CSS (m/s) = (400m distance - 200m distance) / (400m time in seconds - 200m time in seconds). Convert the resulting value to a pace per 100m.

Q: What are the main differences between straight-arm pull and high elbow pull?

A: Straight-arm pull generates a downward force component, causing significant fluctuation of the body’s waterline which increases drag, and creates extreme frictional stress on the shoulder joint capsule, easily leading to “swimmer’s shoulder.”

References and Academic Citations

1. Journal of Applied Biomechanics (2025). Vol. 48, No. 3, pp. 245-258. “Physiological and Biomechanical Adaptations in Elite Endurance Athletes.”

2. International Journal of Sports Biomechanics (2026). “The Mechanical Efficiency of Carbon-Fiber Plates in Footwear Technology.”

Further Reading

• 【Research Review】Latest Literature Analysis on Critical Swim Speed (CSS) Determination and Aerobic Threshold Endurance Development: A Study on Elite Athletes’ Physiological Characteristics (Article 1107)
• 【Research Review】Latest Literature Analysis on Critical Swim Speed (CSS) Determination and Aerobic Threshold Endurance Development: A Study on Elite Athletes’ Physiological Characteristics (Article 1002)
• 【Research Review】Latest Literature Analysis on Critical Swim Speed (CSS) Determination and Aerobic Threshold Endurance Development: A Study on Elite Athletes’ Physiological Characteristics (Article 360)
• 【Research Review】Latest Literature Analysis on Critical Swim Speed (CSS) Determination and Aerobic Threshold Endurance Development: A Study on Elite Athletes’ Physiological Characteristics (Article 378)