Saige Hupman

Date of Award

5-2017

Document Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology

First Advisor

James Hokanson, Ph.D.

Second Advisor

Peter McGinnis, Ph.D.

Third Advisor

Larissa True, Ph.D.

Abstract

Lower body positive pressure (LBPP) treadmills are growing in popularity for rehabilitative use, as the benefits of exercising at partially supported body weight may induce faster recovery. It is unknown if there are certain practices that increase exercise intensity while maintaining positive effects of LBPP. Adding ankle weights when walking or running could increase intensity of rehabilitation programs while maintaining the comfort of supported body weight. PURPOSE: To measure metabolic response (VO2, RER, HR, Caloric expenditure), RPE, and lower limb electromyography (EMG) amplitudes of LBPP treadmill walking and running with and without ankle weights. METHODS: Sixteen participants (Age: 21.94 ± 1.44 years; Height: 1.66 ± 0.15 m; Weight: 66.86 ± 18.25 kg) completed two randomly-selected, separate sessions of 4 min. walking at 1.34 m·s-1 and 4 min. running at 2.68 m·s-1 in LBPP: (a) in a no weight (NW) condition and (b) an ankle weight (AKW) condition, both at 60% body weight (40% of body weight supported). RESULTS: Participants’ average (±SD) relative VO2 was 10.37±1.49 and 20.33±3.38 mlO2/kg/min for NW at the two treadmill speeds. AKW VO2 was 12.2±1.46 and 23.29±4.86 mlO2/kg/min. RER for NW was .89±.064 and .95±.063; RER with AKW was .87±.061 and .96±.077. HR at the NW condition was 103.2±17.3 and 140.0±21.1 bpm; AKW condition HR was 99.36±13.3 and 143.8±20.3 bpm. Caloric expenditure at the NW condition was 14.4±4.90 kcal at the fourth minute of walk and 28.1±9.16 kcal after the complete eight minutes. At the AKW condition caloric expenditure was 16.8±4.77 kcal at the fourth minute of walk and 31.9±10.2 kcal after the complete eight minutes. For the NW condition RPE was 7±1 and 9±2, and 7±1 and 11±1 at the AKW condition. EMG data RMS were calculated then normalized to 100% body weight and expressed as a percent. The maximum peak values from 30s recordings were averaged to represent final EMG amplitudes. EMG of the gastrocnemius at the NW condition was 560.5±181.9 for walk and 485.0±124.6% for run; at the AKW condition EMG of the gastrocnemius was 586.5±237.6% and 461.2±171.7%. EMG of the tibialis anterior at the NW condition was 570.4±158.9 and 647.7±443.5%. At the AKW condition EMG of the tibialis anterior was 581.2±363.3 and 546.9±377.2%. Lastly, the EMG of the vastus medialis at the NW condition was 606.7±441.8 and 448.2±316.0%; at the AKW condition EMG of the vastus medialis was 521.8±537.0 and 633.3±629.9%. A two-way repeated measures ANOVA indicated a statistically significant interaction of speed and weighted condition for RER, F (1,13) = 4.834, p < .05, partial η 2 = .271. RER was statistically significantly different between both speeds at both conditions. RPE was statistically significantly different at 2.68 m·s-1 between the weighted conditions, F (1,15) = 6.505, p < .05, partial η 2 = .303. The remaining variables did not have significant interactions between speed and weighted condition. CONCLUSION: The NW condition had slightly lower means than the AKW for metabolic and RPE data. Electromyography results did not show a large difference in muscle activity between the NW and AKW conditions. The most notable differences occurred at the running speed for the vastus medialis. It was concluded that the addition of ankle weights had a small effect on increasing metabolic response, rating of perceived exertion, and muscle activity but not enough to substantially increase exercise intensity of walking or running while in LBPP. This practice may be applied to those using the AlterG® that are not confident enough to raise body weight closer to 100%, but want to increase intensity via rating of perceived exertion.

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