Shoe Material Effects on Foot Temperature during Treadmill Running Erin M. Poss,1 Brogan L. Austin,2 Gwendolyn J. Baumgardner,3 Nicholas M. Budden4, Shauna-Kaye V. Campbell,4 Samantha J. Carlson,4 Ty C. Drake,5 Guy M. Eckman,4 Kelly L. Lawrence,4 Holly M. Nelson,4 Rachel M. Barkley,1 David S. Senchina6 1Biochemistry, Cell, and Molecular Biology Program; 2College of Education; 3College of Journalism & Mass Communication; 4College of Business & Public Administration; 5College of Pharmacy & Health Sciences; 6Biology Department, Drake University, Des Moines, IA, 50311 ABSTRACT: Running shoes are made from a variety of materials such as leather or mesh. Material type and assembly likely impact on foot heat dynamics during running. The purpose of this study was to investigate how foot temperature during running was modulated by different shoes. All protocols were approved by the Drake IRB (ID 2009-10088). Eleven male subjects (21.6 1.7 yrs) completed four 10-minute running trials at self-selected but constant speeds on a treadmill in four different running shoes (two mesh and two leather). Foot temperature was recorded at two sites on top of the right foot arch (against the skin and between the sock and shoe) for the 10 minutes during running and 5 minutes of resting recovery post-running. Heart rate and subjective ratings of perceived comfort and heat were recorded throughout. There were no statistical differences in foot heat accumulation during running between the shoes. During the 5 minutes postexercise, three of the shoe models accommodated heat dissipation whereas foot temperature in the fourth model significantly increased during rest (all p0.031). Temperature was always greater at the skin site versus the sock site, but fluctuation patterns between the two sites were congruent. Subjects’ rated the mesh shoes as more comfortable than the leather shoes (p=0.016); curiously, however, there were no differences in heat perception across shoes (p=0.184). These results suggest that (a) shoe material influences foot heat dynamics during and immediately after running and (b) subjects’ perceptions of foot temperature may not coincide with actual foot temperature. INTRODUCTION: • The ability of a shoe to dissipate foot heat generated during running may impact on performance in long-distance events and foot health long-term. Uppers can be made from leather or mesh; leather ventilates less but has better structure. Figure 2 Running shoes used in this study (left to right). (a) Adidas Uraha. (b) Adidas_1 DLX. (c) Nike Tailwind. (d) Nike T-Lite VIII. Adidas Uraha Adidas_1 DLX Nike Tailwind Nike T-Lite VIII Skin, 0-10 min +1.98 0.49 +2.18 0.55 +2.37 0.49 +2.06 0.47 Sock, 0-10 min +1.54 0.6 +1.86 0.68 +2.36 0.6 +2.75 0.59 Skin, 10-15 min -0.86 0.46 +1.35 0.52** -0.72 0.46 -0.67 0.45 Sock, 10-15 min +0.17 0.43 +1.65 0.48** -0.28 0.43 -0.6 0.44 Table 1—Changes in foot temperature (expressed as C mean standard error) by time point and site. Asterisks indicate a statistically significant difference (p<0.05) for that cell compared to others in its same row. • Since 70% of sweat production occurs on the upper foot (and hence the bulk of evaporative cooling; ), it is the best location for measuring foot temperature. METHODS: Figure 1. Sites for attachment of the 2 thermometers, 1 against the skin (top) and 1 at the same site between the sock and the shoe (bottom). Figure 3—Compared to the other 3 shoes, foot temperature in the Adidas_1 DLX shoe continued to increase during rest, resulting in a statistically-significant difference between this shoe and all others at both the skin and sock thermometers (all p0.031). Foot temperature in the other shoes generally decreased during rest (see also Table 1). Table 2—There were significant differences in subjects’ perceptions of shoe comfort (p=0.016). Subjects perceived the Adidas Uraha as significantly more comfortable than the Adidas_1 DLX (p=0.02) and Nike Tailwind (p=0.003) but not the Nike T-Lite VIII (p=0.156). There were no significant differences in subjects’ perceptions of foot temperature between shoes (p=0.184). However, it is notable that the Nike Tailwind (and not the Adidas_1 DLX) had the lowest comfort and highest temperature ratings. DISCUSSION: • During running, foot temperature increased in all shoe models and statistically there was not difference between shoes (Table 1), suggesting that all four models allowed for heat dissipation/retention equivocally whether the upper was made mostly of mesh (Adidas Uraha and Nike Tailwind) or leather (Adidas_1 DLX and Nike T-Lite VIII) (Figure 2). • No studies could be located that examined the relationship between shoe construction and foot temperature. The purpose of this study was to investigate how foot temperature during running was modulated by different shoes. Procedures were pre-approved by the Drake University Institutional Review Board (ID 2009-10088) . Eleven males (21.7 1.7 yrs; stature = 182.0 6.3 cm, 74.8 9.8 kg) who could exercise in size 11.5 shoe, could run for 30 min, and have no precluding medical conditions participated. Subjects visited the lab for one experimental session involving four 10-min treadmill runs (Sole, Inc.) spaced by sitting 10-min rest periods. Trial order was counterbalanced and subjects had to run the same self-selected speed for all 4 trials (average 7.6 0.3 mph). Flexible thermistors (thermometers; YSI, Inc.) were attached to the upper right foot, lateral side midway across the arch using electrical tape, one against the skin and one at the same site between the sock and the shoe (Figure 1). Temperatue was recorded from both sites during the 10-min run and the first 5-min of sitting rest. Subjects all wore a pair of brand new Adidas Climalite socks (53% polyester, 37% cotton, 8% olefin, 1% natural latex, 1% Spandex; Adidas, Inc.) throughout the session. Four different shoes were tested: two with an upper made mostly of mesh (Adidas Uraha and Nike Tailwind) and two with an upper made mostly of leather (Adidas_1 DLX and Nike T-Lite VIII). Shoe masses were as follows: Nike T-Lite VIII=318.8 g, Adidas Uraha=330.8 g, Nike Tailwind=430.9 g, Adidas_1 DLX=457.9 g. By comparison, subjects’ normal running shoes were 355.2 6.3 g. Heart rate was recorded throughout but no significant changes were documented and the data is not shown. Subjects’ self-rated perceptions of comfort and stability were assessed independently via 10-cm visual analogue scale (1) where subjects placed a mark along the scale where they perceived foot temperature or comfort, accordingly (see Table 2 for more explanation). Subjects were allowed water ad libitum. Univariate ANOVA was used for statistical analyses (SPSS, Inc.) RESULTS: Table 1—During running, there were no significant differences in foot temperature change at either the skin thermometer (p=0.945) or sock thermometer (p=0.514). During post-exercise rest, there were significant differences in foot temperature change at both the skin and sock thermometers (both p=0.012; see also Figure 3). Figure 3—Changes in foot temperature (expressed as C mean standard error) during rest at both the skin thermometer (a) and sock thermometer (b) sites. Adidas Uraha Adidas_1 DLX Nike Tailwind Nike T-Lite VIII Comfort 6.5 0.7 4.0 0.8 3.3 0.7 5.1 0.7 Heat 3.7 0.7 4.5 0.8 5.8 0.7 4.3 0.7 Table 2—Subjects’ perceptions of comfort and heat and assessed via a 10-cm visual analogue scale. A “0” indicates most uncomfortable/hot imaginable and a “10” indicates most comfortable/cool imaginable. Values are mean standard error • During post-exercise rest, foot temperature decreased in all shoe models except the Adidas_1 DLX at both skin and sock thermometer sites (Figure 3). Foot temperature in the Adidas_1 DLX increased during rest, suggesting that its upper did not allow for heat transfer like the uppers of the other 3 shoes did. The difference between heat dynamics when running or resting may be explained by ventilatory properties or how the shoe interacts with air flow during run or rest. • Subjects perceived differences in shoe comfort but, curiously, not heat (Table 2). The 2 most comfortable shoes were the Adidas Uraha with a mesh upper and the Nike T-Lite VIII with a leather upper. Other aspects of shoe construction such as the midsole or last may be bigger determinants of shoe comfort than the upper. • Subjects’ perceptons of how hot the shoes felt were not statistically different (Table 2) despite actual temperature differences (Table 1), suggesting that the runners’ perceptions of foot temperature were influenced by more than just actual temperature, congruent with others’ findings (2). REFERENCES: (1) Mills K, Blanch P, Vicenzio B (2010). Medicine & Science in Sports & Exercise 42(10): 1966-1971. (2) Purvis AJ and Tunstall H (2004). Ergonomics 47(15): 1657-1668. (3) Taylor NA, Caldwell JN, Mekjavic IB (2006). Aviation, Space, and Environmental Medicine 77(10): 1020-1027. Microbial Growth On Dining Hall Surfaces Erin M. Poss, James Ley Department of Biology, Drake University Figure 1: Microbial growth on (from left to right) 1. Nutrient agar plates inoculated at Hubble South 2. Nutrient agar plates inoculated at Spikes 3. Fecal coliform plates inoculated at Hubble South 4. Fecal coliform plates inoculated at Spikes.