Does a Validated Circum-menarcheal Arm Bone-Loading Index Predict Post-menarcheal Muscle Function in Adolescent...

Area of Science:

• Orthopedics and Sports Medicine
• Human Physiology
• Biomechanical Engineering

Background:

• The 3-year circum-menarcheal arm bone loading index (ᴀʀᴍBLI) is a validated measure of bone loading exposure prior to menarche.
• Understanding predictors of upper extremity muscle function in adolescent females is crucial for optimizing training and injury prevention.

Purpose of the Study:

• To evaluate the 3-year circum-menarcheal arm bone loading index (ᴀʀᴍBLI) as a predictor of upper extremity muscle function in post-menarcheal females.

Main Methods:

• Forty-eight post-menarcheal females (1-2.5 years post-menarche) were analyzed.
• Muscle function was assessed via grip strength and Biodex peak torques (shoulder, elbow).
• Multiple linear regression models incorporated menarche-centered age, anthropometry, arm non-bone fat-free mass, and ᴀʀᴍBLI.

Main Results:

• The ᴀʀᴍBLI was a significant negative predictor of grip strength in the total sample and non-gymnast subsample.
• Conversely, ᴀʀᴍBLI positively predicted shoulder flexion peak torque in the total sample.
• These associations were observed after accounting for whole-body and hypertrophy-related factors.

Conclusions:

• The ᴀʀᴍBLI demonstrated inconsistent predictive value for upper extremity muscle function indices in this cohort.
• While predicting grip strength and shoulder flexion torque, its overall utility requires further investigation.