Vertical Ice Climbing and Snowshoeing

Transcription

1 Technology and Innovation, Vol. 15, pp , /14 $ Printed in the USA. All rights reserved. DOI: Copyright 2014 Cognizant Comm. Corp. E-ISSN X Transtibial Amputee Energy Expenditure During Vertical Ice Climbing and Snowshoeing M. Jason Highsmith,* Jason T. Kahle,* Derek J. Lura, and Larry J. Mengelkoch *School of Physical Therapy and Rehabilitation Sciences, University of South Florida, Tampa, FL, USA Center for Neuromusculoskeletal Research, University of South Florida, Tampa, FL, USA Department of Mechanical Engineering, University of South Florida, Tampa, FL, USA University of St. Augustine for Health Sciences, St. Augustine, FL, USA Beyond running, little is known about energy expenditure measurements during adventure-type activities for persons with lower extremity amputation. The purpose of this study was to determine energy expenditure for a transtibial amputee (TTA) during a prolonged snowshoeing trek and a vertical ice climb. The subject, a unilateral TTA using a multifunction prosthesis, participated in an arctic wilderness survival training course in Denali, Alaska. While training, heart rate (HR) measurements were recorded continuously during a 1-h snowshoeing trek to a vertical ice climb site. To determine how field activities compare to peak energy expenditure, the subject participated in a laboratory-based, maximal effort exercise test. Metabolic data were collected using the COSMED K4b 2 system to determine peak oxygen uptake (VO 2 ) and HR and actual values of HR at any given %VO 2 peak. During maximal exercise, VO 2 peak = ml*kg 1 *min 1 and HR peak = beats*min 1. During the 60-min snowshoeing trek, relative energy expenditure ranged from 21.1 to 30.7 ml*kg 1 *min 1 = 55% to 80% VO 2 peak. During the 24-min, 18.3-m vertical ice climb, relative energy expenditure ranged from approximately 22.1 to 31.5 ml*kg 1 *min 1 = 58% to 81% VO 2 peak. The relative energy expenditure levels for these activities were performed at moderate to vigorous intensity. Energy expenditure was similar to current metabolic equivalent (MET) data reported for nonamputee subjects during moderate to vigorous intensity snowshoeing activities. This study further demonstrates that some persons with TTA may be capable of performing adventure-type activities at relative energy expenditure levels similar to nonamputee subjects. Key words: Amputation; Metabolics; Mountaineering; Oxygen uptake (VO 2 ); Physical therapy; Rehabilitation INTRODUCTION Obstacles such as driveways, lawns, and poorly accessible buildings can be challenging and are encountered by many who ambulate in the community. However, some people face far more difficult environments. Such people may include soldiers, construction workers, rescue workers, and recreational mountaineers. Maneuvering on snow and ice-covered mountains and glaciers involves multiple mobility skills including typical walking, specialized walking patterns, and at times, climbing (6). Little is documented about the latter two tasks particularly with respect to field-collected data, especially in persons with lower limb amputation. Persons with transtibial amputation (TTA) have highly variable prognoses and functional abilities (3,4,7). In some tasks for persons with TTA, functional performance may be comparable to that of nonamputees (3). Beyond running, however, little is known about energy expenditure measurements for persons with TTA during vigorous sport and adventure- type activities. Accepted April 8, Address Correspondence to M. Jason Highsmith, University of South Florida, School of Physical Therapy and Rehabilitation Sciences, Bruce B. Downs Blvd. MDC077, Tampa, FL 33612, USA. Tel: ; Fax: ; mhighsmi@health.usf.edu 311

2 312 HIghsmith ET AL. The purpose of this study was to determine the energy expenditure for a unilateral TTA during a prolonged snowshoeing trek and a vertical ice climb. METHODS The participant was a 41-year-old military veteran with left unilateral TTA secondary to trauma in His residual limb, with long posterior flap closure, was well healed but was only 47% of the length of the uninvolved side limb. He was 183 cm tall and weighed 104 kg. Since his amputation (8 years prior to data collection), he used a multifunction prosthesis that included a cushioned liner and a total surface bearing laminated socket. His prosthetic foot was a sleeve-suspended Freedom Innovations Renegade (Irvine, California, USA). The subject had both mountaineering and arctic survival experience as part of his previous military career. In this project, the subject participated in an arctic wilderness survival training course (Alaska Mountaineering School, Talkeetna, Alaska, USA) on the Coffee Glacier in Denali, Alaska. While completing the course, heart rate (HR) measurements were recorded continuously using a Polar RS800CX HR monitor (Lake Success, NY, USA) during a 1-h snowshoeing trek to the 18.3-m (60 ft) tall and 62 sloped ice climb site (Fig. 1). While trekking to the ice wall, the participant wore snow boots, snow shoes, used ice poles bilaterally while carrying a 20-lb backpack (containing food, additional clothing, prosthetic supplies, climbing rigging, and gear) (Fig. 1). The snowshoeing trek consisted of progressive and gradual snow mounds across a consistent altitude of 1,783 m (5,850 ft) (Fig. 1). The participant walked in a four-person rope team for safe passage across the glacier. Once at the ice climbing site, the team instructor set up a top-rope belay using an ice anchor and trained each member in both one and two ice axe climbing techniques. The participant performed the climb while belayed using a two-axe climbing technique while wearing crampons over the tread of his snow boots (Fig. 2). He climbed without his field pack on. Ratings of perceived exertion (RPE) were measured using Borg s RPE 6-20 scale (2) immediately following both the trek and ice climb tasks in the field. To determine how these field activities compare to peak energy expenditure, the participant performed a laboratory-based, maximal effort exercise test while using his specialty running prosthesis (Fig. 2). The exercise test used a continuous treadmill walking and running protocol with 2-min increments at each speed. The test began at 40.2 m*min 1 (1.5 mi*h 1 ) and speed increased to 13.4 m*min 1 (1.5 mi*h 1 ) every 2 min. Self-selected walking and Figure 1. (A) Rope teams approaching and staging to climb the ice wall. (B) Participant demonstrating gear and footwear during trek to ice wall. Snow shoes were worn over his snow boots, and ski poles were used for stability. (C) Rope teams trekking across Coffee Glacier in single file formation.

3 TRANSTIBIAL AMPUTEE ENERGY EXPENDITURE 313 Figure 2. (A) Participant climbing the ice wall wearing crampons over snow boots using a two-axe climbing technique, while top rope belayed. (B) Participant making a volume-related adjustment to his prosthesis on the trek back to base camp postclimb. (C) Investigator (J.H.) taking an immediate posttrek RPE and discussing limb and prosthetic issues with participant. (D) Participant completing laboratory-based treadmill test using specialty running foot. running speeds determined prior to the exercise test were included in the test protocol. The test was stopped when the subject indicated he reached his maximal exercise tolerance. Borg s RPE (6 20 scale) was measured in the final seconds of each 2-min stage (2). Metabolic data were collected continuously using the COSMED K4b 2 system (Rome, Italy) to determine peak oxygen uptake (VO 2 ) and HR. Actual values of HR were then determined at Table 1. Heart Rate Values at Various Percentages of VO 2 Peaks %VO 2 Peak Measured VO 2 (ml*kg 1 *min 1 ) Measured HR (beats*min 1 ) any given percentage of VO IP: peak (Table 1). On: Sat, 22 Sep :26:11

4 314 HIghsmith ET AL. RESULTS During maximal exercise, the participant s VO 2 peak was ml*kg 1 *min 1, and HR peak was beats*min 1 (Fig. 3A). The participant s RPE at VO 2 peak was 19/20, which occurred at m*min 1 (6.5 mi*h 1 ). During the 60-min snowshoeing trek, relative energy expenditure ranged from 21.1 to 30.7 ml*kg 1 *min 1, which was 55% to 80% VO 2 peak (Fig. 3B). His RPE immediately following the trek was 11/20. During the 24-min, 18.3-m ice climb, relative energy expenditure ranged from approximately 22.1 to 31.5 ml*kg 1 *min 1, which was 58% to 81% VO 2 peak (Fig. 3C). Immediately following the ice climb, his RPE was 17/20. DISCUSSION We previously reported the metabolic demands of indoor rock climbing in transfemoral amputees. We reported that persons with unilateral transfemoral amputation can participate in the sport and have multiple prosthetic options with which to do so. Specialty climbing prostheses and no prostheses may provide the best scenario with which to participate (5). To our knowledge, this report represents the first attempt to define the bioenergetic demands and relative difficulty of this activity in the amputee population. The implications have utility for sport enthusiasts and those with associated occupational demands. For instance, the U.S. military is retaining persons with amputation following injury, and these soldiers may encounter difficult environments, conditions, and tasks such as those previously discussed (8,9). The energy expenditure data for persons with TTA indicate that snowshoeing and ice climbing were performed with moderate (40% to 59% VO 2 peak) to vigorous (>60% VO 2 peak) intensity. Furthermore, Figure 3. (A) Mean VO 2 (circles and dashed line) and HR (squares and solid line) responses during maximal exercise test. (B) Mean HR during 1-h snowshoeing trek. (C) Mean HR during 18.3-m ice climb.

5 TRANSTIBIAL AMPUTEE ENERGY EXPENDITURE 315 the data indicate that energy expenditure was similar to current metabolic equivalent (MET) data reported for nonamputee subjects during moderate to vigorous intensity snowshoeing activities (approximately 8.6 to 35.0 ml*kg 1 *min 1 ) (1). While not represented in the data, additional relevant insights were observed. For example, the survival course required multiple days of camping and maneuvering on the glacier. The subject tended to remove the prosthesis from his residual leg to rest, but he did not remove his footwear from the prosthesis. This led to ice getting into the shoe and prosthetic foot where it eventually melted to water. This caused sanitary issues as well as slippage of the prosthetic foot shell upon the foot structure during movement. Additionally, issues associated with general hydration caused a surprising amount of volume loss of the residual leg, which required volume management strategies such as the addition of prosthetic socks (Fig. 2B). A third observation concerned the reduced amount of force that the TTA subject had available with which to kick the crampon into the ice during ice climbing compared to nonamputees in the group. Subjectively, this appeared to increase the effort when climbing up with the prosthetic side. However, nonamputee data would be necessary to determine if this is the case. Finally, related to both the aforementioned volume and reduced kick force issues, at times, when the TTA climber would attempt to kick the crampon/ prosthetic limb into the ice, the prosthesis would rotate laterally, and the leg required repeated and multiple attempts to land a secure kick and footing upon which to climb. Thus, while the task was able to be completed successfully, these factors should be taken into account when planning such tasks and preparing the associated gear. LIMITATIONS This is a case study that limits generalizability. Furthermore, not having comparable data on nonamputees limits the ability to compare the relative difficulty between these two groups. CONCLUSION Snowshoeing and ice climbing activities can be performed by some persons with TTA at moderate to vigorous intensity levels. There are challenges related to prosthetic side stability and kick force. Ultimately, with consideration to the aforementioned challenges, this study further demonstrates that high-functioning persons with TTA are capable of performing some sport and adventure-type activities at relative energy expenditure levels similar to nonamputee subjects. ACKNOWLEDGMENT: The authors declare no conflict of interest. REFERENCES 1. Ainsworth, B. E.; Haskell, W. L.; Herrmann, S. D.; Meckes, N.; Bassett, D. R. Jr.; Tudor-Locke, C.; Greer, J. L.; Vezina, J.; Whitt-Glover, M. C.; Leon, A. S. Compendium of physical activities: A second update of codes and MET values. Med. Sci. Sports Exerc. 43: ; Borg, G. A. Psychophysical basis of perceived exertion. Med. Sci. Sports Exerc. 14: ; Brown, M. B.; Millard-Stafford, M. L.; Allison, A. R. Running-specific prostheses permit energy cost similar to nonamputees. Med. Sci. Sports Exerc. 41: ; Czerniecki, J. M.; Turner, A. P.; Williams, R. M.; Hakimi, K. N.; Norvell, D. C. Mobility changes in individuals with dysvascular amputation from the presurgical period to 12 months postamputation. Arch. Phys. Med. Rehabil. 93: ; Highsmith, M. J.; Kahle, J. T.; Fox, J. L.; Shaw, K. L.; Quillen, W. S.; Mengelkoch, L. J. Metabolic demands of rock climbing in transfemoral amputees. Int. J. Sports Med. 31:38 43; Highsmith, M. J.; Kahle, J. T.; Quillen, W. S.; Mengelkoch, L. J. Spatiotemporal parameters and step activity of a specialized stepping pattern used by a transtibial amputee during a Denali mountaineering expedition. J. Prosthet. Orthot. 24: ; Kegel, B.; Carpenter, M. L.; Burgess, E. M. Functional capabilities of lower extremity amputees. Arch. Phys. Med. Rehabil. 59: ; Kishbaugh, D.; Dillingham, T. R.; Howard, R. S.; Sinnott, M. W.; Belandres, P. V. Amputee soldiers and their return to active duty. Mil. Med. 160:82 84; Stinner, D. J.; Burns, T. C.; Kirk, K. L.; Ficke, J. R. Return to duty rate of amputee soldiers in the current conflicts in Afghanistan and Iraq. J. Trauma 68: ; 2010.