Energy Expenditure and Substrate Utilization with Hands-Free Crutches Compared to Conventional Lower-Extremity Injury Mobility Devices

Abstract

Background: A Hands-Free crutch (HFC) is a relatively new device that can be used during the nonweightbearing period to increase mobility. The primary aim of this investigation was to examine aerobic oxygen consumption (V.o2) and substrate utilization with HFC compared to conventional ambulation devices as well as normal ambulation. A secondary purpose was to quantify perceived exertion, pain, and performance during each ambulation condition. Methods: Forty participants completed 4 separate 10-minute ambulation conditions around a rectangular course. The order of the ambulation conditions was randomized and consisted of (1) walking, (2) medical knee scooter (MKS), (3) HFC, and (4) axillary crutch (AC). Indirect calorimetry was used to determine V.o2 and the respiratory exchange ratio (RER), an indicator of substrate utilization. Perceived exertion and pain were also assessed using questionnaires. Results: All mobility devices significantly elevated V.o2 (+35%) compared to walking (13.14 ± 1.70 mL/kg/min; P < .001). AC had significantly greater V.o2 requirements (20.26 ± 2.62 mL/kg/min) compared to both the MKS (15.28 ± 2.29 mL/kg/min; P < .001) and HFC (15.88 ± 2.03 mL/kg/min; P < .001). There was no difference in average V.o2 between MKS and HFC ( P = .368). Compared to walking (0.78 ± 0.43), RER was significantly elevated in MKS (0.81 ± 0.05, P < .001) and AC (0.84 ± 0.06, P < .001), but not in HFC (0.79 ± 0.04, P = .350). RPE and pain were elevated in all ambulatory conditions (all P values <.001). Pain was significantly greater in AC compared with MKS ( P < .001) and HFC ( P < .001). Conclusion: HFC and MKS share similar V.o2 requirements over a 10-minute ambulation interval and are below those needed in AC. Substrate utilization in HFC was similar to regular walking with a greater reliance on lipid utilization for energy as evidenced by a lower RER. Exertion and pain scores were the most tolerable in HFC and MKS. Level of Evidence: Level II, prospective comparative study.

Walking with unilateral ankle-foot unloading: a comparative biomechanical analysis of three assistive devices

“…2 b). The CR and IW results are consistent with previous research [ 34 , 35 ]. Moreover, these results correspond well with the participants’ rated perceived exertion, which was significantly higher for CR, albeit comparable between IW and ZG.…”

“…Moreover, these results correspond well with the participants’ rated perceived exertion, which was significantly higher for CR, albeit comparable between IW and ZG. These differences in perceived exertion ratings between CR and IW are consistent with previous studies [ 23 , 34 ]. The higher walking speed and lower metabolic cost of ZG support our hypothesis that the ZG would lead to a more natural gait pattern, resulting in a faster and more energetically efficient gait.…”

“…2 a). Similarly, previous studies reported significantly slower walking using IW compared to NG [ 24 , 34 ] and significantly faster walking with IW compared to CR [ 35 ]. Contrary to our findings, other studies found that participants walked slower with IW than with CR.…”

“…Contrary to our findings, other studies found that participants walked slower with IW than with CR. However, they used axillary crutches [ 23 , 34 ]. We selected forearm crutches based on their overall superior performance over axillary crutches reported in terms of walking speed, metabolic cost, and pressure on the upper extremities [ 5 ].…”

Biomechanical Analysis of the Unaffected Limb While Using a Hands-Free Crutch

“…Secondly, mobility is significantly reduced. Ambulation speed is decreased, even though there is a twofold increase in the energy demand compared with that of natural gait [ 16 , 17 , 18 , 19 , 20 ]. Thirdly, pain in the underarm, shoulder, ribs, and hands through the prolonged use of SACs can cause lasting nerve damage [ 12 , 21 , 22 ].…”