The Reliability of Individualized Load-Velocity Profiles

Area of Science:

• Biomechanics
• Sports Science
• Strength and Conditioning

Background:

• Load-velocity profiles (LVP) are used to assess neuromuscular function.
• Reliability of different velocity measures in LVP development is crucial for accurate assessment.

Purpose of the Study:

• To determine the reliability of peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) for creating load-velocity profiles (LVP).
• To assess these measures during the full-depth free-weight back squat with maximal concentric effort.

Main Methods:

• Eighteen resistance-trained men completed multiple 1-repetition maximum (1-RM) back-squat trials at various relative loads (20-100% 1-RM).
• Reliability was assessed using intraclass correlation coefficient (ICC), coefficient of variation (CV), and Cohen d effect size (ES).
• Individualized LVPs were derived from loads meeting reliability criteria (ICC > .70, CV ≤ 10%, ES < 0.60).

Main Results:

• Peak velocity (PV) demonstrated high reliability across all tested loads (20-100% 1-RM).
• Mean propulsive velocity (MPV) and mean velocity (MV) were highly reliable from 20% to 90% 1-RM, but not at 100% 1-RM.
• LVPs derived from PV (20-100%), MPV (20-90%), and MV (20-90%) showed strong correlations and were not significantly different between trials or fitting methods.

Conclusions:

• Peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) are reliable for developing load-velocity profiles (LVP) within specific load ranges (PV: 20-100%; MPV & MV: 20-90%).
• Linear regression is a suitable method for deriving LVPs.
• LVPs can be effectively used for monitoring changes in movement velocity and adjusting training loads based on daily readiness.