Lack of Training: A Source of Underutilization of Hand-Held Dynamometry for Quantitative Strength Testing
Purpose/Hypothesis: Strength is a critical component of human movement routinely evaluated by physical therapists (PTs). PTs traditionally use Manual Muscle Testing (MMT) grades 0 to 5 to assess strength; but MMT lacks objectivity beyond a grade of 3/5. Hand Held Dynamometry (HHD) has been available for decades to quantify strength objectively. Stark et al. state that portable HHD device measurements differ minimally from gold-standard isokinetic results. Despite this, the authors have observed only rare PT use of HHD across practice settings. The purpose of this survey was to test the hypothesis that HHD is underutilized in PT practice due to lack of HHD availability, experience and training and to therapist doubts regarding reliability.
Number of Subjects: 131 PTs in a large academic medical center.
Materials and Methods: We sent an anonymous 20-question survey using Research Electronic Data Capture (REDCap) to all PTs in a major academic medical center to investigate PTs’ training, knowledge, use, experience, and opinions regarding MMT and HHD strength testing. Respondents were limited to one submission. IRB review determined that the study is not human subjects research.
Results: Survey respondents (n=131) working in a variety of inpatient and outpatient settings believe strength testing to be very or moderately important for establishing the plan of care (93%). These PTs use MMT more than weekly (80%) but express dissatisfaction with the MMT scale for tracking patient strength (65%). Eighty-nine percent of the PTs believe MMT scores to be objective for the 0/5 grade; 70% for the 1/5 grade; 55% for 2/5; 74% for 3/5; 29% for 4/5; and 45% for 5/5. Most PTs are familiar with HHD (77%) but report minimal to no experience with HHD (84%). Common reasons for not using HHD were: Inadequate training (35%); no access to an HHD device (33%); unfamiliar with HHD devices (29%). Overall, 48% believe HHD is underutilized for strength testing and 49% were unsure, while 53% would use HHD if trained. HHD reliability was an issue for only 5%.
Conclusions: Survey results from 131 medical center PTs support our hypothesis that HHD is underutilized due to lack of availability, experience, education and training, but do not support that HHD reliability is a PT concern. The survey reveals mixed understanding of the limited objectivity of MMT but suggests PTs might use HHD if trained.
Clinical Relevance: While strength testing is critically important for assessing and tracking strength, traditional MMT lacks objectivity above the grade of 3/5 whereas HHD provides reliable quantitative measurement for these grades. We found that PTs lack HHD knowledge, education, and clinical training. These findings support the need for HHD entry-level and post-professional education and training if this objective quantitative measurement tool is to be widely adopted in clinical practice. Further research is recommended to investigate the generalizability of these results and to determine the amount of training PTs and PT students need to achieve HHD proficiency.