Elsevier

Clinical Biomechanics

Volume 80, December 2020, 105106
Clinical Biomechanics

Lecture
Effects of elbow immobilization on upper extremity activity

https://doi.org/10.1016/j.clinbiomech.2020.105106Get rights and content

Highlights

  • Elbow immobilization caused forearm and upper arm activity to be comparable.

  • Arm dominance did not have a significant effect on asymmetry index.

  • Regardless of arm immobilized, individuals relied on contralateral limb twice as much.

Abstract

Background

It has been dogma that handedness greatly impacts daily activities. Interruptions in the ability to utilize the dominant arm due to neuromusculoskeletal injuries could negatively impact performance of activities of daily living. Daily activity can be measured using activity monitors. This study aimed to examine how arm dominance impacts function by immobilizing the arms of healthy individuals.

Methods

Ten individuals wore four upper extremity activity monitors for three days—one day without immobilization, one day with their dominant arm immobilized, and one day with their non-dominant arm immobilized. Triaxial acceleration data was used to calculate average daily activity and an asymmetry index. Between-condition differences were examined.

Findings

During dominant arm immobilization, the dominant forearm had significantly less average daily activity when compared to the no immobilization day (p = .0001) and the non-dominant immobilized day (p < .0001). A similar trend was observed at the non-dominant forearm when the non-dominant arm was immobilized. Immobilization of an arm increased asymmetry index and reliance on the non-immobilized arm. Significant differences in asymmetry index were not observed between the two casted conditions.

Interpretation

When an upper extremity was casted, immobilized forearm and upper arm average daily activity was comparable. Dominance did not have an effect on asymmetry index. Immobilization affected asymmetry index compared to no immobilization. This study has demonstrated that regardless of arm immobilized, there will be a reliance on the contralateral limb about twice as much as the immobilized limb. This could prove problematic if the contralateral limb is restricted or injured, limiting independent.

Introduction

It has been dogma that upper extremity dominance greatly impacts daily functional activities. Previous studies have demonstrated dominant and non-dominant arms are each optimized for performance of unique functions (Bagesteiro and Sainburg, 2002; Przybyla et al., 2012; Sainburg, 2005). The dominant arm is optimized for control of limb trajectory, while the non-dominant limb is optimized for limb positioning. The coordination of these complementary systems allows for optimizing neural resources to seamlessly execute activities of daily living, especially bimanual tasks (Przybyla et al., 2012). Interruptions in the ability to utilize the dominant arm due to neuromusculoskeletal injuries or conditions could negatively impact performance of activities of daily living. Many neuromusculoskeletal injuries and conditions affect multiple joints and motions, making it difficult to identify any impact arm dominance has on function in these cases.

Daily functional activity can be measured and recorded using activity monitors. This application of accelerometry utilizes triaxial accelerometers to record motions of a segment in the free-living environment. These methods have been used for both upper (Bailey and Lang, 2013; Hurd et al., 2013; Uswatte et al., 2005) and lower (Fortune et al., 2014; Fortune et al., 2017; Mathie et al., 2003) extremity applications to provide an indication of functional usage. Various quantities can be extracted and calculated from the raw acceleration data recorded by activity monitors. Average daily activity has been indicative of overall function (Uswatte et al., 2005; Uswatte et al., 2006). The use of an asymmetry index has been used to gauge impact of treatment in shoulder arthroscopy (Hurd et al., 2013), stroke (Lang et al., 2007; Noorkõiv et al., 2014), and brachial plexus injury (Webber et al., 2019). This measure allows for reliance on the dominant side to be quantified. Previous studies using this real world data have reported that healthy individuals have symmetrical usage of their upper extremities throughout the day, regardless of dominance (Hurd et al., 2013; Lang et al., 2007; Rand and Eng, 2010).

To explore the effect of upper extremity dominance on daily functional activity in an injured population, this study immobilized the upper extremities of a group of healthy individuals to simulate restricted elbow and wrist function that could be cause by a neuromusculoskeletal injury or condition. It was hypothesized that upper extremity dominance affects average daily activity. The null hypothesis was that no differences in asymmetry index would exist between immobilized and non-immobilized conditions.

Section snippets

Subjects

Ten subjects (9 male; 1 female) with no prior neuromusculoskeletal conditions of their back, neck, shoulders, or arms participated in this Institutional Review Board (IRB) approved study after providing informed consent. Subjects (mean ± standard deviation age: 28.2 ± 5.3 years) were recruited by word of mouth to reflect the clinical population studied in a previous investigation into upper extremity activity (Webber et al., 2019). They were remunerated for their time upon completion of the

Wear time

Wear time averaged 10 h for each condition (Table 1). Since the wear time was constrained by study design for the days when subjects were immobilized, between condition differences were not explored.

Average daily activity

Average daily activity (Fig. 1) was normally distributed for all segments (dominant forearm, p = .269; non-dominant forearm, p = .649; dominant upper arm, p = .526; and non-dominant upper arm, p = .155). When the dominant arm was immobilized, the dominant forearm had significantly less average daily

Discussion

During this study, upper extremity activity of healthy subjects was monitored in three different conditions—no immobilization, dominant arm immobilized, and non-dominant arm immobilized. The immobilized conditions simulated restricted elbow and wrist motion that could be caused by any neuromusculoskeletal injury. Casted healthy subjects were used to make the present study more broadly applicable, eliminating potential effects that concomitant injuries in a clinical population could have on

Conclusion

Activity of the upper extremity during periods of restricted motion was collected and analyzed. There was no effect of dominance on Ax; however, there was an effect of immobilization on Ax when compared to a no immobilization condition, as expected. Regardless of the arm immobilized, an individual will rely on the contralateral side about twice as much as the immobilized arm. This must be taken into consideration clinically, as independent function after trauma will be dependent upon the

Author contributions

CMW, AYS, and KRK all contributed to the conception and design of the work. Data collection was conducted by CMW. Data analysis and interpretation was conducted by CMW, AYS, and KRK. CMW drafted the initial article, with AYS and KRK providing critical revisions. The final version of the article for publication was approved by all authors (CMW, AYS, KRK).

Funding sources

Fellowship funding (CMW) was provided by NIH T32-AR056950 and Mayo Clinic Graduate School of Biomedical Sciences. Additional support provided by a generous Mayo Clinic benefactor who wishes to remain anonymous. Sponsors had no involvement in the planning, execution, or analysis of this study.

Declaration of Competing Interest

The authors have no conflicts of interest to disclose.

Acknowledgements

The authors would like to thank Tracy Waters, M.S.N., R.N. for her assistance in the cast room.

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