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Modifications in Wheelchair Propulsion Technique with Speed.

Russell IM, Raina S, Requejo PS, Wilcox RR, Mulroy S, McNitt-Gray JL - Front Bioeng Biotechnol (2015)

Bottom Line: Upper extremity kinematics and kinetics were compared within subject between propulsion speeds.Reorientation of the RF relative to the upper extremity segments can be used as an effective strategy for mitigating rotational demands (NJM) imposed on the shoulder at increased propulsion speeds.Identification of propulsion strategies that individuals can use to effectively accommodate for increases in RFs is an important step toward preserving musculoskeletal health of the shoulder and improving health-related quality of life.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of Southern California , Los Angeles, CA , USA.

ABSTRACT

Objective: Repetitive loading of the upper limb joints during manual wheelchair (WC) propulsion (WCP) has been identified as a factor that contributes to shoulder pain, leading to loss of independence and decreased quality of life. The purpose of this study was to determine how individual manual WC users with paraplegia modify propulsion mechanics to accommodate expected increases in reaction forces (RFs) generated at the pushrim with self-selected increases in WCP speed.

Methods: Upper extremity kinematics and pushrim RFs were measured for 40 experienced manual WC users with paraplegia while propelling on a stationary ergometer at self-selected free and fast propulsion speeds. Upper extremity kinematics and kinetics were compared within subject between propulsion speeds. Between group and within-subject differences were determined (α = 0.05).

Results: Increased propulsion speed was accompanied by increases in RF magnitude (22 of 40, >10 N) and shoulder net joint moment (NJM, 15 of 40, >10 Nm) and decreases in pushrim contact duration. Within-subject comparison indicated that 27% of participants modified their WCP mechanics with increases in speed by regulating RF orientation relative to the upper extremity segments.

Conclusions: Reorientation of the RF relative to the upper extremity segments can be used as an effective strategy for mitigating rotational demands (NJM) imposed on the shoulder at increased propulsion speeds. Identification of propulsion strategies that individuals can use to effectively accommodate for increases in RFs is an important step toward preserving musculoskeletal health of the shoulder and improving health-related quality of life.

No MeSH data available.


Related in: MedlinePlus

(A) Effect of RF orientation relative to the upper extremity segments for three example subjects with comparable propulsion velocities and RF magnitudes. Free body diagrams are drawn for fast speed condition at the time of peak push. Note elbow NJMs are in opposite directions for the anterior and posterior examples and how that affects shoulder NJM. (B) Population grouping of RF component orientation in the armplane (plane that connects shoulder, elbow, and wrist) relative to the upper extremity at the time of peak push. Orientation is grouped into posterior (more than 5° behind the forearm), anterior (more than 5° in front of the forearm), and in line (within 5° posterior or anterior).
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Figure 8: (A) Effect of RF orientation relative to the upper extremity segments for three example subjects with comparable propulsion velocities and RF magnitudes. Free body diagrams are drawn for fast speed condition at the time of peak push. Note elbow NJMs are in opposite directions for the anterior and posterior examples and how that affects shoulder NJM. (B) Population grouping of RF component orientation in the armplane (plane that connects shoulder, elbow, and wrist) relative to the upper extremity at the time of peak push. Orientation is grouped into posterior (more than 5° behind the forearm), anterior (more than 5° in front of the forearm), and in line (within 5° posterior or anterior).

Mentions: In some cases, individuals were able to mitigate increases in the rotational demand imposed on the shoulder with increases in WCP speed, whereas others were not. For example, the three exemplar participants achieved comparable fast WCP velocities with comparable RF magnitudes at peak push (Figure 8A). However, the magnitude of the shoulder NJM depended on the proximal distal moments created by the NJFs about the center of mass (CM) of the forearm and upper arm segments as well as the adjacent joint NJM at the elbow. When the RF is oriented anterior to the forearm CM, an elbow extensor NJM is needed to achieve the observed motion. The elbow extensor NJM applied to the upper arm contributes to the reduction in magnitude of the shoulder NJM. In contrast, when the RF is oriented posterior to the forearm CM, an elbow flexor NJM is needed to achieve the observed motion. The elbow flexor NJM applied to the upper arm contributes to the increase in magnitude of the shoulder NJM.


Modifications in Wheelchair Propulsion Technique with Speed.

Russell IM, Raina S, Requejo PS, Wilcox RR, Mulroy S, McNitt-Gray JL - Front Bioeng Biotechnol (2015)

(A) Effect of RF orientation relative to the upper extremity segments for three example subjects with comparable propulsion velocities and RF magnitudes. Free body diagrams are drawn for fast speed condition at the time of peak push. Note elbow NJMs are in opposite directions for the anterior and posterior examples and how that affects shoulder NJM. (B) Population grouping of RF component orientation in the armplane (plane that connects shoulder, elbow, and wrist) relative to the upper extremity at the time of peak push. Orientation is grouped into posterior (more than 5° behind the forearm), anterior (more than 5° in front of the forearm), and in line (within 5° posterior or anterior).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4620433&req=5

Figure 8: (A) Effect of RF orientation relative to the upper extremity segments for three example subjects with comparable propulsion velocities and RF magnitudes. Free body diagrams are drawn for fast speed condition at the time of peak push. Note elbow NJMs are in opposite directions for the anterior and posterior examples and how that affects shoulder NJM. (B) Population grouping of RF component orientation in the armplane (plane that connects shoulder, elbow, and wrist) relative to the upper extremity at the time of peak push. Orientation is grouped into posterior (more than 5° behind the forearm), anterior (more than 5° in front of the forearm), and in line (within 5° posterior or anterior).
Mentions: In some cases, individuals were able to mitigate increases in the rotational demand imposed on the shoulder with increases in WCP speed, whereas others were not. For example, the three exemplar participants achieved comparable fast WCP velocities with comparable RF magnitudes at peak push (Figure 8A). However, the magnitude of the shoulder NJM depended on the proximal distal moments created by the NJFs about the center of mass (CM) of the forearm and upper arm segments as well as the adjacent joint NJM at the elbow. When the RF is oriented anterior to the forearm CM, an elbow extensor NJM is needed to achieve the observed motion. The elbow extensor NJM applied to the upper arm contributes to the reduction in magnitude of the shoulder NJM. In contrast, when the RF is oriented posterior to the forearm CM, an elbow flexor NJM is needed to achieve the observed motion. The elbow flexor NJM applied to the upper arm contributes to the increase in magnitude of the shoulder NJM.

Bottom Line: Upper extremity kinematics and kinetics were compared within subject between propulsion speeds.Reorientation of the RF relative to the upper extremity segments can be used as an effective strategy for mitigating rotational demands (NJM) imposed on the shoulder at increased propulsion speeds.Identification of propulsion strategies that individuals can use to effectively accommodate for increases in RFs is an important step toward preserving musculoskeletal health of the shoulder and improving health-related quality of life.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of Southern California , Los Angeles, CA , USA.

ABSTRACT

Objective: Repetitive loading of the upper limb joints during manual wheelchair (WC) propulsion (WCP) has been identified as a factor that contributes to shoulder pain, leading to loss of independence and decreased quality of life. The purpose of this study was to determine how individual manual WC users with paraplegia modify propulsion mechanics to accommodate expected increases in reaction forces (RFs) generated at the pushrim with self-selected increases in WCP speed.

Methods: Upper extremity kinematics and pushrim RFs were measured for 40 experienced manual WC users with paraplegia while propelling on a stationary ergometer at self-selected free and fast propulsion speeds. Upper extremity kinematics and kinetics were compared within subject between propulsion speeds. Between group and within-subject differences were determined (α = 0.05).

Results: Increased propulsion speed was accompanied by increases in RF magnitude (22 of 40, >10 N) and shoulder net joint moment (NJM, 15 of 40, >10 Nm) and decreases in pushrim contact duration. Within-subject comparison indicated that 27% of participants modified their WCP mechanics with increases in speed by regulating RF orientation relative to the upper extremity segments.

Conclusions: Reorientation of the RF relative to the upper extremity segments can be used as an effective strategy for mitigating rotational demands (NJM) imposed on the shoulder at increased propulsion speeds. Identification of propulsion strategies that individuals can use to effectively accommodate for increases in RFs is an important step toward preserving musculoskeletal health of the shoulder and improving health-related quality of life.

No MeSH data available.


Related in: MedlinePlus