Validation of ankle strength measurements by means of a hand-held dynamometer in adult healthy subjects

Uniaxial Hand-Held Dynamometer (HHD) is a low-cost device widely adopted in clinical practice to measure muscle force. HHD measurements depend on operator’s ability and joint movements. The aim of the work is to validate the use of a commercial HHD in both dorsiflexion and plantarflexion ankle strength measurements quantifying the effects of HHD misplacements and unwanted foot’s movements on the measurements. We used an optoelectronic system and a multicomponent load cell to quantify the sources of error in the manual assessment of the ankle strength due to both the operator’s ability to hold still the HHD and the transversal components of the exerted force that are usually neglected in clinical routine. Results showed that foot’s movements and angular misplacements of HHD on sagittal and horizontal planes were relevant sources of inaccuracy on the strength assessment. Moreover, ankle dorsiflexion and plantarflexion force measurements presented an inaccuracy less than 2% and higher than 10%, respectively. In conclusion, the manual use of a uniaxial HHD is not recommend ed for the assessment of ankle plantarflexion strength; on the contrary, it can be allowed asking the operator to pay strong attention to the HHD positioning in ankle dorsiflexion strength measurements

Analysis of knee strength measurements performed by a hand-held multicomponent dynamometer and optoelectronic system

The quantification of muscle weakness is useful to evaluate the health status and performance of patients and athletes. In this paper, we proposed a novel methodology to investigate and to quantify the effects induced by inaccuracy sources occurring when using a hand-held dynamometer (HHD) for knee strength measurements. The validation methodology is based on the comparison between the output of a one-component commercial HHD and the outputs of a six-component load cell, comparable in dimension and mass. An optoelectronic system was used to measure HHD positioning angles and displacements. The setup allowed to investigate the effects induced by: 1) the operator's ability to place and to hold still the HHD and 2) ignoring the transversal components of the force exchanged. The main finding was that the use of a single component HHD induced an overall inaccuracy of 5% in the strength measurements if the angular misplacements are kept within the values found in this paper (≤15°) and with a knee range of motion ≤22°. Extension trials were the most critical due to the higher force exerted, i.e., 249.4 ± 27.3 versus 146.4 ± 23.9 N of knee flexion. The most relevant source of inaccuracy was identified in the angular displacement on the horizontal plane

Physical assessment to improve the identification of modifiable physiological fall risk factors in healthy community-dwelling older adults

As the population aged >60 years grows, the number of people falling and subsequent injury increases. Falls have a devastating effect on older adults living in the community in terms of morbidity, mortality, and loss of independence. In general, a positive answer to falls screening questions, or opportunistic identification of fall risk through primary care pathways, establishes an older adult as being at risk of a fall and warrants further investigation using multifactorial fall risk assessments (MFRA). At the MFRA stage, standardised fall risk assessment tools are directed at identifying the presence of physiological impairments and risk of falling in older adults. Although these tools identify which intervention domain a person needs, information from these assessments does not inform the health professional of the underlying causes of poor physical function and performance. Therefore, the purpose of this project was to develop an assessment tool that may potentially identify modifiable fall risk factors in this population. A conceptual framework for objectively measuring modifiable physical impairments and a novel assessment procedure (Performance Deficit Test for Community-dwelling older adults (PDT-Com)) were introduced (Chapter 2). This was followed by a brief description of the scoring criteria of the PDT-Com assessment and discussion of the validity of its contents (Chapters 3 and 4). Chapter 5 reviewed current literature on falls prevention guidelines and assessment procedures which identified a need to better detect modifiable risk factors. The first study was a systematic review examining the objective measurement of lower-extremity muscle strength in community-dwelling older adults (Chapter 6). The second study was another systematic review (Chapter 7) examining current assessment tools which are used to identify modifiable functional status and fall risk factors in this population. The results further supported the need for a newly designed assessment tool that can objectively measure modifiable physical impairments to better inform the contents of an exercise intervention. The first experimental study (Chapter 7) was carried out to determine reference values of strength for ten lower-extremity muscle actions using hand-held dynamometry in a small cohort of community-dwelling older adults. These data were used to develop an objective scoring system. A second experimental study (Chapter 8) investigated intra- and inter-rater reliability of the PDT-Com in community-dwelling older adults. Assessment of movement competency is reliable and can confidently be applied by suitably trained individuals when a standardised procedure is used. A final experimental study examined the effect and feasibility of a three-month home and group exercise intervention directed by initial assessment using the PDT-Com. For the experimental group, a corrective exercise programme was prescribed based on each person’s PDT-Com score. The mean total PDT-Com scores for the exercise group were significantly improved compared to baseline scores. Conversely, mean PDT-Com scores in the control group marginally decreased over time from baseline scores. Between groups differences in mean PDT-Com scores were observed between groups suggesting that those subjects receiving an individualised exercise programme improved their physical function compared to the control group. This new assessment tool is a promising but untested approach to reducing falls and falls-related injury through the identification, and possible causes, of modifiable fall risk factors at the MFRA stage. A physiological assessment paradigm serves to promote a primary preventative approach to the management of falls in active community-dwelling older adults

Stereophotogrammetry in human movement analysis: novel methods for the quality assurance, biomechanical analysis and clinical interpretation of gait analysis

The study of movement has always fascinated artists, photographers and researchers. Across the years, several attempts to capture, freeze, study and reproduce motion were made. Nowadays, motion capture plays an important role within many fields, from graphical animation, filmmaking, virtual reality, till medicine. In fact, movement analysis allows to measure kinematic and kinetic performance of the human body. The quantitative data obtained from measurements may support the diagnosis and treatment of many pathologies, allowing to take clinical decisions and supporting the follow-up of treatments or rehabilitation. This approach is nowadays named evidence based medicine. In this work, motion capture techniques and advanced signal processing techniques were exploited in order to: (i) develop a protocol for the validation and quality assurance of the clinical strength measurements, (ii) develop an algorithm for clinical gait analysis data interpretation and identification of pathological patterns, and (iii) design user-friendly software tools to help clinicians using the novel data processing algorithms and reporting the results of measurements. This work was divided into three sections: Part 1 contains a survey about the history of motion analysis and a review of the earliest experiments in biomechanics. The review covered the first historical attempts, that were mainly based on photography, till the state-of-the-art technology used today, i.e. the optoelectronic system. The working principle of optoelectronic system was reviewed as well as its applications and modern setups in the clinical practice. Some modern functional evaluation protocols, aimed to the quantitative evaluation of physical performance and clinical diagnosis of motor disorders, were also reviewed. Special attention was paid to the most common motion analysis exam that is nowadays worldwide standardized, i.e. the Gait Analysis. Examples of Gait Analysis studies on subjects with pathology and follow-up were reviewed. Part 2 concerns the design of an experimental setup, involving motion analysis, for the quality assurance of clinical strength measurements. Measurements of force are popular in the clinical practice as they allow to evaluate the muscle weakness, health status of patients and the effects of therapies. A variety of protocols was proposed to conduct such measurements, implying the acquisition of forces, angles and angular velocities when the maximum voluntary force is exerted. Hand held dynamometry (HHD), based on single component load cell, was extensively used in clinical practice; however, several shortcomings were identified. The most relevant were related to the operator’s ability. This work was aimed to investigate the inherent inaccuracy sources in knee strength measurements when are conducted by a single component load cell. The analysis was conducted by gathering the outputs of a compact six-component load cell, comparable in dimension and mass to clinical HHDs, and an optoelectronic system. Quality of measurements was investigated in terms of quantifying, by an ad-hoc metrics, the effects induced in the overall inaccuracy by: (i) the operator’s ability to place and to hold still the HHD and (ii) ignoring the transversal components of the force exchanged between the patient and the experimenter. The main finding was that the use of a single component HHD induced an overall inaccuracy of 5% in the strength measurements, when operated by a trained clinician and angular misplacements are kept within the values found in this work (≤15°) and with a knee ROM ≤ 22°. Even if the measurement outputs were reliable and accurate enough for both knee flexion and extension, extension trials were the most critical due to the higher force exerted, i.e. 249.4±27.3 N vs. 146.4±23.9 N of knee flexion. The most relevant source of inaccuracy was identified in the angular displacement of HHD on the horizontal plane. A dedicated software, with graphical user interface, was designed and implemented. The purposes of this software were to: (i) speed up data processing, (ii) allow user to select the proper processing workflow, and (iii) provide clinicians with a tool for quick data processing and reporting. Part 3 concerns the research study about gait analysis on subjects with pathology. Gait analysis is often used for the assessment of the gait abilities in children with cerebral palsy and to quantify improvements/variations after a treatment. To simplify GA interpretation and to quantify deviation from normality, some synthetic descriptors were developed in literature, such as the Movement Analysis Profile (MAP) and the Linear Fit Method (LFM). The aims of this work were: (i) to use synthetic descriptors in order to quantify gait variations in subjects with Cerebral Palsy that underwent surgery involving bone repositioning and muscle/tendon lengthening at the level of the femur and hamstring group (SEMLS); (ii) test the effectiveness of a recently proposed index, i.e. the LFM, on such patients; (iii) design and implement a novel index that may overcome the limitations of the previous methods. Gait Analysis exams of 10 children with Cerebral Palsy, pre and post treatment, were collected. Data were analysed by means of MAP and LFM indices. To overcome the limitations observed for the methods, another index was designed as a modified version of the MAP, namely the OC-MAP. It took into account the effect on deviation due to offset and allowed to compute the deviation from normality on tracks purified by the offset. An overall improvement of the gait pattern was observed for most of the subjects after surgery. The highest effect was observed for the knee flexion/extension angle. Patients who had initial high deviations also had the largest improvements. Worsening in the kinematics of the pelvis could be explained as a consequence of SEML involving a lengthening of hamstring group. Pre-post differences were higher than the Minimally Clinical Important Difference for all parameters, except hip flexion. An improvement towards normality was observed for all the parameters, with exception of pelvic tilt for which a worsening was observed. LFM provided results similar to OC-MAP offset analysis but could not be considered reliable due to intrinsic limitations. As offset in gait features played an important role in gait deviation, OC-MAP synthetic analysis is recommended to study gait pattern of subjects with Cerebral Palsy. A dedicated software, with graphical user interface, was designed and implemented. The purpose of this software was to compute the synthetic descriptors on a large amount of data, to speedup data processing and to provide clinicians with a quick access to the result

A randomised controlled trial of twelve months protein supplementation on muscle mass and strength in elderly women

Background. Aging is associated with progressive loss of muscle (sarcopenia), which can lead to reduced muscle strength and an increased risk of falls. Sarcopenia exists in otherwise healthy elderly people and its aetiology is not fully understood. Many epidemiological studies have shown that high protein intake is associated with preserving muscle mass and strength in the elderly. To date there have been few randomized trials of sufficient duration and power to examine the effects of dietary protein supplement on muscle mass and strength in the elderly. The objective of this study was to examine the effectiveness of whey protein supplementation on preventing sarcopenia in elderly women.Methods. A population based, one-year randomized, double blind and placebo controlled trial of protein supplementation was conducted on 219 community-dwelling ambulant women aged 70 to 80 years. Participants in the protein supplement group (n=109) consumed a drink daily which contained 30 g of protein. The control group (n=110) consumed a drink with the same energy (kilojoules) but only contained 2 g of protein. Assessments were taken at baseline and one year. Body composition was assessed by anthropometry and whole body dual-energy x-ray absorptiometry. Peripheral quantitative computer tomography was used to assess calf muscle crosssectional area. Hand grip, ankle dorsiflexion, knee and hip strengths were assessed using an isokinetic dynamometer. Mobility was assessed by the ‘Timed Up and Go’ test. Standing balance was assessed by the Romberg test. Dietary intake was assessed by a 3-day weighed food record. Compliance with the dietary intervention was assessed by 24-hour urinary nitrogen and by counting the returned empty supplement containers. Serum insulin-like growth factor one (IGF-1) was also measured.Results. One-hundred and ninety-five participants aged 74±3 years completed the one year trial. There were no significant differences in baseline characteristics between the protein supplemented group (n=100) and control group (n=95). Compared to their baseline values, both groups significantly increased whole body lean mass (protein group: +1.6%, p<0.05; control group: +2.3%, p<0.05), appendicular lean mass (protein group: +1.3%, p<0.05; control group: +1.8%, p<0.05), body weight (protein group: +0.8%, p<0.05; control group: +1.5%, p<0.05) and knee strength (protein group: +31%, p< 0.05; control group: +36%, p<0.05) after one year. The total fat mass increased from baseline only in the control group (protein group: +0.7%, p=0.19; control group: +1.5%, p<0.05). There were however no significant differences between the two drink groups in any of the above mentioned parameters. Over one year serum IGF-1 increased significantly in the protein group but decreased in the control group (protein group: +7.6%, p = 0.006; control group: -1.0%, p = 0.005), and the changes were significantly different between two drink groups (p = 0.006). The protein supplement also showed a protective effect on preserving balance function at one year. The prevalence of ‘poor standing balance’ and ‘fall rates’ were significantly increased in the control group at one year.Conclusion. Muscle mass and strength increased equally in both drink groups. Although fat mass only increased in the control group at one year there was no statistically significant difference in the changes in fat mass between the two groups due to the wide variance in response. Protein supplementation resulted in an increased serum IGF-1 level at one year compared with the control group. These data are consistent with the concept that in this age group increased energy intake regardless of the macronutrient composition of the supplements improves muscle mass and function. It is possible that achieving this through increased protein rather than carbohydrate may prevent the increase in fat mass noted with the carbohydrate supplement for the control drink perhaps by an effect of the protein to increase serum IGF-1. The metabolic significance of this remains to be explored

Gait and balance characteristics after a non-cerebellar stroke

One of the most common neurological injuries in the elderly is a stroke event, affecting nearly 800,000 adults in the U.S. alone every year. Since falls occur at a rate of 73% per year with people who are more than six months past the stroke event compared to approximately 30% with aged matched healthy, the potential consequences for injury are devastating. Current literature does not completely address the specific deficits in gait and balance after a stroke. To resolve this problem, the purpose of this thesis was to compare gait mechanics to clinical tests that indicate fall risks in 20 healthy elderly adults (63.4±8.9) and 7 non-cerebellar/non-brain stem post-stroke survivors (57.6±7.7). The dependent variables for gait were step width, step length, stride length, step time and stride time. The metrics of mean, standard deviation (SD), coefficient of variation (CoV), detrended fluctuation analysis alpha (DFA &amp;#945;) and sample entropy (SampEn) were calculated for each dependent variable. Further, the Timed Up and Go (TUG), Berg balance assessment (Berg), Functional Gait Assessment (FGA), Activities-Specific Balance Confidence Scale (ABC), lower extremity strength, and lower extremity flexibility were all taken as clinical assessments. The data showed that most dependent variables for mean, SD, and CoV were different between groups, whereas DFA &amp;#945; and SampEn generally were not. The TUG, Berg, FGA, and ABC showed group differences. No differences in strength or flexibility were observed between the unaffected limbs of the stroke survivor group and matched limbs of the healthy elderly group. However, significant differences were observed in strength and flexibility between the affected and matched limbs between groups. Sixty-four out of a possible 200 correlations between the gait and clinical metrics were significant. These data suggest that summary metrics (mean, SD, and CoV) may be the strongest indicators of gait dysfunction after a stroke

Knee Extensor Strength Prediction Formula Using Modified Aneroid Sphygmomanometer in Healthy Female Adults

Objective: To discover isometric knee extensor muscle strength prediction formula using hand-held dynamometer (HHD) through the use of modified aneroid sphygmomanometer (MAS). Isometric knee extensor muscle strength examination is required to diagnose and evaluate the treatment of quadriceps femoris weakness. Methods: This was a quantitative observational and correlational analysis study with cross-sectional design. Isometric knee extensor muscle strength was measured using HHD and MAS with 60o knee flexion in sitting position. Correlation tests were performed to investigate the correlation between HHD, MAS, and other variables. Regression test was carried out to analyze knee extensor strength regression using HHD through MAS. Results: Subjects enrolled were 25 healthy females aged 23–52 years old. The correlation between HHD and MAS was significant while age, body weight, body height, and body mass index (BMI) did not show correlation with HHD and MAS. The isometric knee extensor muscle strength using HHD could be predicted by formula = 0.1041xMAS. Conclusions: Isometric knee extensor muscle strength measured using HHD strongly correlates with that of using MAS with 60o knee flexion in sitting position and can be predicted from measurement values of MAS. The formula is only suitable for females