Predicting 1 Repetition Maximum Using Handheld Dynamometry

Area of Science:

• Exercise Physiology
• Musculoskeletal Biomechanics
• Clinical Assessment

Background:

• Isometric strength assessment using handheld dynamometers (HHD) is common in clinics, but its validity for monitoring dynamic performance changes is debated.
• One repetition maximum (1RM) is the gold standard for dynamic strength but is not frequently used by clinicians due to caution with impaired clients.
• Predicting 1RM from HHD strength testing could significantly impact exercise prescription in clinical environments.

Purpose of the Study:

• To determine the relationship and agreement between 1RM and HHD isometric strength scores for biceps and quadriceps.
• To assess the predictive capability of HHD measurements for 1RM strength.

Main Methods:

• Criterion standard comparison involving 50 healthy adults (19-33 years).
• Muscle strength measured using 1RM and HHD isometric maximal voluntary contraction for biceps and quadriceps.
• Statistical analysis included Pearson correlation, Bland-Altman plots, and linear regression with covariates (gender, age, training history, BMI).

Main Results:

• A significant correlation was found between 1RM and HHD scores for both biceps (r = .83) and quadriceps (r = .82).
• While scores did not agree, linear regression showed HHD scores could significantly predict 1RM (P < .001).
• Gender was a significant covariate influencing 1RM prediction for both muscle groups (P = .005 for biceps, P = .003 for quadriceps).

Conclusions:

• A significant relationship exists between 1RM and HHD strength measures.
• HHD measurements can effectively predict 1RM for biceps and quadriceps muscle groups.
• HHD presents a more accessible alternative for muscle strength assessment compared to 1RM, though further clinical population research is needed.