FES-rowing attenuates bone loss following spinal cord injury as assessed by HR-pQCT

Abstract

Neurologically motor complete spinal cord injury (SCI) presents a unique model of bone loss whereby specific regional sites are exposed to a complete loss of voluntary muscle-induced skeletal loading against gravity. This results in a high rate of bone loss, especially in the lower limbs where trabecular bone mass decreases by~50-60% and cortical bone mass decreases by 25-34% before the rate of bone loss slows. These SCI-induced losses that are likely superimposed on continual age-related bone losses, increase the risk of low-impact fragility fracture. The fracture incidence 20 years post SCI is reported to be 4.6% per year. An intervention that effectively prevents, attenuates, or reverses bone loss is therefore highly desirable. We present a case study of an individual with chronic complete SCI, where bone loss has been attenuated following long-term functional electrical stimulation (FES)-rowing training. In this case study, we characterize the ultradistal tibia and ultradistal radius of the FES-rower with chronic complete SCI using high-resolution-peripheral quantitative computed tomography. These data are compared with a group of FESuntrained individuals with chronic complete SCI and to a normative non-SCI cohort. The evidence suggests, albeit from a single individual, that long-term FES-rowing training can attenuate bone loss secondary to chronic complete SCI. Indeed, key FES-rower's bone metrics for the ultradistal tibia more closely resemble normative age-matched values, which may have clinical significance since the majority of fragility fractures in chronic SCI occur in the lower extremities. Neurologically motor complete spinal cord injury (SCI) presents a unique model of bone loss whereby specific regional sites are exposed to a complete loss of voluntary muscle-induced skeletal loading against gravity. The initial loss of bone mineral content is estimated to approach 4% per month in trabecular sites, and 2% per month in cortical sites. Spinal Cord Series and Cases1 Trabecular bone mass is estimated to decrease by 48% of pre-injury values in the femur, reaching a new slower rate of loss by 3 years and 58% in the tibia by 5 years. Cortical bone mass decreases by 34% of pre-injury values in the femur by 5 years, and 25% in the tibia by 7 years.2 These losses are likely superimposed on continual age-related bone loss.3 SCIinduced bone loss often leads to the development of osteoporosis, which increases the risk of low-impact fragility fracture. 4 The fracture incidence 20 years post SCI is reported to be 4.6% per year.5 Thus, even active individuals with complete SCI at age 20 undergoing conventional standard of care have a very high likelihood of sustaining a fragility fracture in their lifetime, markedly affecting quality of life and increasing the risk of mortality. 6 An intervention that effectively prevents, attenuates or reverses bone loss is therefore highly desirable. 7One such intervention under investigation is functional electrical stimulation (FES) rowing. 8 In the present configuration, FES...

Development of Functional Electrical Stimulation Rowing: The Rowstim Series

“…Indeed, more recently, males and females with complete paraplegia and tetraplegia have demonstrated the ability to achieve steady‐state V̇ O 2 values of 15.2 ± 1.8 mL/kg/min in individuals with tetraplegia and 22.9 ± 7.1 mL/kg/min in individuals with paraplegia during 30‐min FES‐rowing training bouts. These values approach the recommended 21 mL/kg/min vigorous intensity threshold with accumulated training volumes fulfill these guidelines .…”

“…Recent pilot studies suggest that a structured program of FES rowing may prevent the onset of CVD in chronic SCI, and mitigate SCI‐induced osteoporosis . Furthermore, an increase in steady‐state power output can be expected providing training compliance is maintained .…”

“…Recent pilot studies suggest that a structured program of FES rowing may prevent the onset of CVD in chronic SCI, and mitigate SCI‐induced osteoporosis . Furthermore, an increase in steady‐state power output can be expected providing training compliance is maintained . Importantly, the volume and intensity of FES rowing training represents a dramatic increase in physical activity above normal ADL, especially in tetraplegia .…”

“…Furthermore, an increase in steady‐state power output can be expected providing training compliance is maintained . Importantly, the volume and intensity of FES rowing training represents a dramatic increase in physical activity above normal ADL, especially in tetraplegia . Recently, we have reported significant force actions during FES rowing, exceeding 1.5 times BW, which have produced widely distributed stresses in the tibia, a bone highly susceptible to fragility fracture following SCI .…”

Effects of FES‐Rowing Exercise on the Time‐Dependent Changes in Bone Microarchitecture After Spinal Cord Injury: A Cross‐Sectional Investigation

“…FES‐rowing actively engages the leg muscles and dynamically loads the bones; hence, FES‐rowing may alter the time‐dependent tibial bone loss seen after injury. We used HR‐pQCT to assess bone microarchitecture cross‐sectionally in men with SCI who had regularly trained with FES‐rowing.…”