Does Negative Heel Shoes Alter A Person's Exercising Metabolism As Advertised

PURPOSE: This study determined the effects negative heel (NH) shoes (3.7% negative heel design) had on walking metabolic efficiency, EMG, and gait in 17 subjects (13 male; 4 female). This abstract focuses on only the metabolic efficiency data. METHODS: Each subject completed 2 trials in both the NH and standard running shoes (SR), respectively. Maximal and submaximal metabolic responses were measured comparing VO2, VCO2, RER, heart rate, substrate utilization and total steady-state energy expenditure after a 7-10 day accommodation period. RESULTS: VO2 max test-retest results showed exceptional reliability for each shoe (NH r-value=.97, SEE=1.1 ml, P=.0001; SR r-value=.98, SEE= 1.1ml, P=.0001). The VO2 max correlation between NH and SR shoes showed a r-value=.89, SEE= 1.42ml, and P= >.0001. The VO2 max results showed there were no significant differences observed, indicating equal max performances for each shoe and all trials. Steady-state V02 results indicated no significant differences between NH and SR shoes' oxygen uptake at 0% grade and 3.7% grade at 3.0 mph. These results repudiate the manufacturer's claim that NH shoes, due to 3.7% negative heel design, will increase a person's metabolic demand during walking exercise. Fat and carbohydrate (CHO) substrate utilization responses at steady state were also not significantly different between shoes when walking at 3.0 mph & either 0% or 3.7% grade. However, as expected, there were a greater total amount of kcals expended and CHO utilized when walking at 3.7 % compared to 0% grade in both shoes. Steady state heart rate results showed near significant increases while wearing NH compared to SR shoes when walking at both 0% and 3.7 % grades (p =.06) However, this may only be due to using untrained muscles not in use when walking in normal running shoes. As expected, total kcal expenditure between shoe types showed no significant differences after 20 minutes of walking at a 0% grade (NH = 258kcals; SR= 253kcals). CONCLUSIONS: These results indicate negative heel shoe design did not alter a person's oxygen consumption, kcal expenditure, or substrate utilization usage (fat versus CHO) compared to standard exercise shoes as advertised by the NH shoe company.