Adjusted saddle position counteracts the modified muscle activation patterns during uphill cycling

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Steep uphill cycling (UC) presents unique biomechanical demands compared to level cycling (LC).
• Understanding muscle activation patterns is crucial for optimizing performance and comfort during intense cycling efforts.

Purpose of the Study:

• To investigate muscle activity patterns during 20% gradient UC.
• To evaluate the effect of an adjusted saddle position (ASP) on muscle activity during 20% UC.
• To compare muscle activation during 20% UC with ASP to LC.

Main Methods:

• Electromyography (EMG) was used to record muscle activity from eight key leg muscles in 12 trained cyclists.
• Cyclists performed cycling tests at 80% maximal power output and 90 rpm under three conditions: LC, 20% UC, and 20% UC with ASP.
• ASP involved moving the saddle forward and tilting it by 20%.

Main Results:

• Compared to LC, 20% UC significantly altered muscle activation timing and intensity, especially for hip muscles like the rectus femoris (RF) and gluteus maximus (GM).
• RF showed later onset, earlier offset, reduced activity range, and decreased peak amplitude (-34%).
• GM showed increased peak amplitude (+44%), and biceps femoris (BF) exhibited a longer activity range during 20% UC.
• ASP successfully counteracted the altered EMG patterns observed during 20% UC, making them resemble those of LC.
• All cyclists reported positive perceptions of comfort and performance with ASP during 20% UC.

Conclusions:

• Steep uphill cycling elicits distinct muscle activation strategies compared to level cycling, with significant hip musculature involvement.
• Adjusted saddle position (ASP) effectively normalizes muscle activity patterns during steep uphill cycling.
• ASP offers a practical method to potentially enhance performance and reduce discomfort during steep uphill cycling.