Test-Retest Reliability and Minimum Difference Values of a Novel and Portable Upright Row Strength Assessment in Probation Officers

Upper body (UB) strength is important for occupational tasks and injury prevention in law enforcement officers (LEOs). Portable, reliable, and cost-effective assessments are needed to examine UB strength among LEOs in field settings. The purpose of this study was to examine the test-retest reliability and minimum difference (MD) values of a novel and portable isometric upright row assessment in probation officers. Thirty certified probation officers (18 women; age = 38.9 ± 9.0 years, body mass = 98.8 ± 27.1 kg, stature = 171.4 ± 14.0 cm) volunteered for this investigation. Testing occurred on-site across two sessions (2-5 days apart). Participants stood upon an aluminum plate with a chain attached to a handle and dynamometer. They grasped the handle with a pronated grip, two cm below the umbilicus, and performed three isometric maximal voluntary contractions. Intraclass correlation coefficient (ICC2,1), standard error of the measurement (SEM), and MD values were calculated. Results indicated no significant systematic error (p = 0.080) across sessions. The ICC2,1, SEM, and MD values for UB strength were 0.984, 27.20 N (4.1% of the mean), and 75.38 N (11.3% of the mean), respectively. These data suggest this isometric upright row assessment is a reliable, portable, and cost-effective measure of UB strength to assess and monitor LEOs in field settings.

Examining Additional Aspects of Muscle Function with a Digital Handgrip Dynamometer and Accelerometer in Older Adults: A Pilot Study

Background: Maximal handgrip strength (HGS) could be an incomplete and unidimensional measure of muscle function. This pilot study sought to examine the relationships between maximal HGS, radial and ulnar digit grip strength, submaximal HGS force control, HGS fatigability, neuromuscular HGS steadiness, and HGS asymmetry in older adults. Methods: A digital handgrip dynamometer and accelerometer was used to collect several HGS measurements from 13 adults aged 70.9 ± 4.0 years: maximal strength, radial and ulnar digit grip strength, submaximal force control, fatigability, neuromuscular steadiness, and asymmetry. Pearson correlations determined the relationships between individual HGS measurements. A principal component analysis was used to derive a collection of new uncorrelated variables from the HGS measures we examined. Results: The individual HGS measurements were differentially correlated. Maximal strength (maximal HGS, radial digit strength, ulnar digits strength), contractile steadiness (maximal HGS steadiness, ulnar digit grip strength steadiness), and functional strength (submaximal HGS force control, HGS fatigability, HGS asymmetry, HGS fatigability steadiness) emerged as dimensions from the HGS measurements that we evaluated. Conclusion: Our findings suggest that these additional measures of muscle function may differ from maximal HGS alone. Continued research is warranted for improving how we assess muscle function with more modern technologies, including handgrip dynamometry and accelerometry.