Validity of a simple sit-to-stand method for assessing force-velocity profile in older adults
Introduction
The “power-force-velocity” approach is based on force and power-velocity (F-v and P-v) relationships characterizing maximal mechanical capabilities of lower limbs' neuromuscular systems (Morin and Samozino, 2016; Samozino et al., 2014). For now, individual F-v profile is widely used in sport performance as it give an optimal individual F-v profile that maximizes lower limb ballistic performance which allows individual determination of force or velocity deficit. These profiles could be very interesting to replicate in geriatrics and aging research as measures of muscle function could allow to screen for an age-related loss of muscle strength and power. Indeed, a loss of muscle function is related to frailty (Batista et al., 2012), risk of disability (Rantanen et al., 1999), and morbidity in older people, all of which can lead to a loss of independence in older people.
To date, Gold Standard for measuring muscle function in clinical practice and research settings is isokinetic dynamometry (Drouin et al., 2004). Nevertheless, those systems that measure force and velocity with accuracy are very expensive and time-consuming which limit their spread in clinics. The recent technological progress involving wearable sensors opens the field of possibilities and allows to replace those costly systems with convenient, simple and accurate analysis of the biomechanical kinematic variables. Samozino et al. (2008) developed their own simple method for having power-force-velocity profiles which can be determined from a series of 2 to 6 loaded vertical squat jumps. In geriatrics, a more adapted exercise is the sit-to-stand (STS) test which is widely used to assess muscle strength (Bohannon, 2006; Bohannon, 2011). Although time to complete STS is the primary measure of function, leg velocity and muscle power also contribute to understanding physical performance but require more sophisticated, time-consuming and expensive assessment tools such as force plates (Lindemann et al., 2003) and/or motion capture system. To avoid those systems, many studies have attempted to evaluate STS movements with either single or multiple accelerometers, both embedded and in smartphones, placed over different regions of the human body (Hellec et al., 2020; Millor et al., 2017; Galán-Mercant and Cuesta-Vargas, 2013). González Rojas et al. (2018) characterize velocity profile during STS transitions with an embedded smartphone placed on L2/L3 vertebrae region while Lepetit et al. (2019) used a single magneto-inertial measurement unit fixed on the chest to quantify velocity, acceleration and kinematic data. All these studies only measure one parameter over leg power, force and velocity which does not allow the assessment of F-v and P-v profiles. To our knowledge, the only study that combines everything is Ruiz-Cárdenas et al. (2018). They developed an App technology to objectively measure time, velocity and leg power during a single STS test. The App was designed for analysing STS via highspeed video recording (240 frames-per-second) allowing the calculation of time between two frames selected by the user and subsequent calculation of mean vertical velocity and vertical power relative to body weight.
Nowadays, the spread of technology enable the development of simple method by only using smartphones or simple devices. Recently, an open library for real-time multi-person key point detection was proposed by Carnegie Mellon University named OpenPose. It is a real-time system to jointly detect 130 human body, hand and facial key points on single images. In addition, its computational performance on body key point estimation is invariant to the number of detected people in the image with high accuracy. OpenPose is freely available for all kinds of free non-commercial use (Cao et al., 2019). This library enable to have every single joint of the body, angular velocities of the joint, and lower limb forces. In our knowledge, yet, no study has used OpenPose to calculate lower limb force and velocity on STS.
As STS has already proved its worth as an effective tool for assessing F-v profiles in clinical geriatric and as OpenPose seems to be a promising one also, combining the two could result in an effective simple method. In this context, the aim of this study was to propose and validate a new simple protocol for determining the F-v and P-v profiles in the hope of using it to detect decline in physical abilities in older adults. The concurrent validity of this method was tested by comparison to reference isokinetic protocol. We hypothesized that force and power variables will be moderately correlated, velocity variables will be poorly correlated with linear association between them reflecting a sufficient concurrent validity.
Section snippets
Participants
A total of 109 community-dwelling older adults aged between 65 and 85 years old were recruited. Exclusion criteria were pathologies that prohibit a maximal strength test, such as severe cardiovascular disease, artificial hip or knee, acute hernia, infection, or tumour. All participant gave written informed consent. Thirty acquisition were not well recorded during STS due to some improper Openpose detection caused by the camera angle, leading to missing data at some velocities (0, 5 or 10kgs).
Results
Mean ± Standard deviation for both STS and BIODEX methods for mean force, velocity and power output are presented in Table 1. Spearman's rank correlation showed no to very low (r = −0.024-0.226) and non-significant (p = 0.08–0.77) for most of the parameters except for Pmax (r = 0.314), Sfv (r = 0.229), a_poly (r = 0.335) and b_poly (r = 0.226) (Table 1). Finally, for all parameters except for Sfv, p-value of the CUSUM test was more than 0.05 (Table 1) concluding in a linear relation between the
Discussion
The objectives of this study were to assess the concurrent validity of a new method to assess F-v and P-v profiles in older adults based on STS protocol comparing it with the well-known isokinetic protocol. Results obtained highlighted a linear relationship between most of the F-v and P-v parameters between the two methods, no proportional difference for F0 and b_poly and a low significant correlation for Pmax (r = 0.314), Sfv (r = 0.229), a_poly (r = 0.335) and b_poly (r = 0.226) whereas the
Funding source
No funding or research grants was needed.
Permission note
Only figures and material which are original content were used.
CRediT authorship contribution statement
All authors have seen and approved the final version of the manuscript being submitted. They warrant that the article is the authors' original work, hasn't received prior publication and isn't under consideration for publication elsewhere.
Declaration of competing interest
No financial/personal interest or belief has been declared.
References (37)
- et al.
The sit-to-stand muscle power test: an easy, inexpensive and portable procedure to assess muscle power in older people
Exp. Gerontol.
(2018) - et al.
The sit-to-stand muscle power test: an easy, inexpensive and portable procedure to assess muscle power in older people
Exp. Gerontol.
(2018) - et al.
Validity, reliability, and measurement error of a sit-to-stand power test in older adults: a pre-registered study
Exp. Gerontol.
(2021) - et al.
Can sit-to-stand lower limb muscle power predict fall status?
Gait Posture
(2014) Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters
J. Biomech.
(1996)- et al.
Optimized scoring tool to quantify the functional performance during the sit-to-stand transition with a magneto-inertial measurement unit
Clin. Biomech.
(2019) - et al.
Validity and reliability of an iPhone app to assess time, velocity and leg power during a sit-to-stand functional performance test
Gait Posture
(2018) - et al.
A simple method for measuring force, velocity and power output during squat jump
J. Biomech.
(2008) - et al.
Force-velocity, force-power relationships of bilateral and unilateral leg multi-joint movements in young and elderly women
J. Biomech.
(2009) - et al.
A body-fixed-sensor-based analysis of power during sit-to-stand movements
Gait Posture
(2010)
The force-velocity relationship in older people: reliability and validity of a systematic procedure
Int. J. Sports Med.
Comparison of linear, hyperbolic and double-hyperbolic models to assess the force–velocity relationship in multi-joint exercises
Eur. J. Sport Sci.
Relationship between lower-limb muscle strength and frailty among elderly people
Sao Paulo Med. J.
Lessons in biostatistics comparison of methods: passing and Bablok regression
Biochem. Med.
Reference values for the five-repetition sit-to-stand test: a descriptive meta-analysis of data from elders
Percept. Mot. Skills
Test-retest reliability of the five-Repetition sit-to-stand test : a systematic review of the literature involving adults
J. Strength Cond. Re.s
Realtime multi-person 2D pose estimation using part affinity fields
IEEE Trans. Pattern Anal. Mach. Intell.
Reliability and validity of the Biodex system 3 pro isokinetic dynamometer velocity, torque and position measurements
Eur. J. Appl. Physiol.
Cited by (2)
Loaded 5 Sit-to-Stand Test to Determine the Force–Velocity Relationship in Older Adults: A Validation Study
2023, Applied Sciences (Switzerland)