The application of strength and power related field tests in older adults: criteria, current status and a future perspective

Abstract

Leg muscle strength (LMS) and leg muscle power (LMP) are determinants of aspects of functional status and important parameters for measuring intervention effects in older adults. Field tests are often used for the evaluation of LMS and LMP in older persons. However, criteria important for the application of strength and power related field tests in older adults have not been systematically taken into account and are not yet fully listed and described in a single publication. Therefore, this paper describes criteria important for the application of strength and power related field tests in older adults. In addition, strength and power related field tests commonly used in older adults are evaluated by using the described criteria. Based on this evaluation, this paper provides a perspective on the further development of field tests. Criteria important for strength and power related field tests are: adequate accuracy, precision, concurrent validity, clinical validity, practical feasibility and pure strength or power outcomes. Commonly used strength and power related field tests do not meet all the aforementioned criteria. Therefore, further development of field tests is necessary. Mobile sensing systems are potentially useful for the evaluation of LMS and LMP in older adults. Mobile sensing systems do not have the limitations of commonly used field tests and provide important additional advantages. In particular, mobile sensing systems offer the opportunity of continuous monitoring during free-movement in the home-environment, thereby reducing the need of standardized assessments by health-care professionals. Future studies should examine the clinical validity of mobile sensing systems and evaluate the application of sensor technology in exercise-based interventions.

Keywords: Aged; Assessment; Muscle power; Muscle strength; Sensor.

Fig. 1

Example of an ROC curve based on fictitious data from a leg power field test. The area under the ROC curve (AUC) is 0.82, indicating a moderately accurate discriminative ability of the field test. The optimal cut-off point is marked with a black circle. The sensitivity and specificity corresponding to the optimal cut-off point are respectively 0.80 and 0.80

Fig. 2

A motion sensor can be used to estimate power during the sit-to-stand movement. The small black box on the right side of the hip represents a body-fixed motion sensor. The vertical acceleration signal measured with the motion sensor can be used to estimate the vertical peak power of the body’s center of mass during the sit-to-stand transfer [40]