The influence of environmental oxygen level on the development and histological characteristics of mammalian bones has only recently begun to be explored by the biological sciences. By utilizing bone histology as the methodology, this research works to identify and analyze the influence of environmental atmospheric hypoxia on the characteristics of the microstructure of mammalian femora. This study focuses on wild caught animals of the order Lagomorpha and the family Sciuridae, provided by the Burke Museum of Natural History. Data was collected on bone wall thickness and a wide variety of mechanical properties in order observe any possible patterns and trends as the amount of oxygen in the environment decreases. The comparison is intra-species, and each animal is collected from a discrete elevational point and compared to animals from higher or lower discrete elevations. By using paleontological preparation methods we can strengthen our ability to make assumptions through evolutionary history and into the fossil record. The implications of this research are possible inferences about the universal effects of elevation, and as a proxy, oxygen level, on the growth and mechanical properties of mammalian bone. Because oxygen is believed to be a macroevolutionary pressure, identifying the physical manifestations of oxygen’s influence within bones would further our broad level understanding of how an organism’s habitat and environment influences the mammalian body.

Understanding the energy expenditure required for the activities of daily living is a critical step in assessing the caloric needs both of those individuals whose body mass exceeds recommended standards and those who are chronically under/malnourished. Knowing how much energy people require to accomplish their activities of daily living, which typically includes walking with burdens (carrying excess weight) and on sloped surfaces, is a critical component in developing guidelines for appropriate caloric intake. Activity energy expenditure is the second largest component of daily energy use, after the energy required to maintain bodily function (usually called resting metabolic rate (RMR)). This study allows us to understand the relationship between burden, gradient and walking which is necessary to accurately account for the daily caloric needs of humans. To evaluate this relationship, data is collected from a large number of female participants. Participants walk at three self-selected velocities (slow, normal, and fast), on five gradients (flat, slight uphill and downhill at a gradient of (6.7%), and steep uphill and downhill at a gradient of (12.6%)) and two burdens (no burden and a burden of a 10 kg backpack).“Self-selected” velocity means that the subjects are able to choose their own pace, be it slow, normal or fast. This approach allows flexibility for the subjects to choose speeds that reflect their normal routine. The energy consumption is measured by the volumetric rate of oxygen consumption (VO2, inspiration) and carbon dioxide (VCO2, expiration) with a portable Cosmed K4b2 device. Unlike previous work that has used treadmills, this study is completed outside in an urban setting. Preliminary results indicate that walking outside requires different energy expenditure than walking on a treadmill. This study provides data collected from real-world experience, thereby providing more accurate understanding of the caloric needs to achieve more day-to-day activities.

 Most kinematic studies using modern human gait to provide insights into the movement of extinct hominins collect data from shod participants. Given that our hominin ancestors were habitually unshod, this methodology is potentially problematic if the kinematics of shod and unshod gait differ. We investigate whether or not differences are present by comparing the movement profiles of the lower limbs in shod and unshod walking. Kinematic data was collected on 20 women using an eight-camera motion capture system. Participants walked at self-selected slow, medium, and fast velocities, performing 30 shod and 30 unshod trials. Average velocities were calculated for each trial, as well as the maximum and minimum angles made by the foot, calf, and thigh during the stride cycle relative to the horizontal (foot) and vertical (calf, thigh) axes in the sagittal plane. Paired t-tests indicated that for all individuals, velocities differed between shod and unshod trials (p<0.01). Linear regression comparing shod and unshod lower limb angles was thus performed including velocity as a variable. Foot (p<0.001) angles differed between shod and unshod trials at all velocities. Additionally, the magnitude of the differences is positively correlated with velocity in all individuals (foot: p<0.001). These observed differences warrant a second look at previous kinematic studies. Future studies should consider using unshod participants to obtain data that is applicable to extinct bipeds.

Arm swing length has been observed to vary with walking velocity. The mechanical function of arm swing as a counterbalance to leg movement has been suggested as an explanation for these observations. If this explanation is valid, then step length should be a better predictor of arm swing length than velocity, even though velocity and step length are correlated. We hypothesize that the variation in arm swing length can be explained more by step length than by walking velocity in shod and unshod walking conditions. Thirteen women completed 30 shod and 30 unshod trials at self-selected slow, medium, and fast velocities. An eight-camera system collected kinematic data by tracking infrared reflective markers placed on participants. For each trial, we calculated average walking velocity and step length from the calcaneal tuberosity and measured two distances that the distal arm travelled in a step: arm swing length measured from the travel of the radial styloid process (RSAL) and the ulnar styloid process (USAL). Arm swing length does not differ between shod and unshod conditions (RSAL: p<0.69; USAL: p<0.74). Using linear regression, arm swing length is significantly associated with both step length (RSAL: p<0.001, r2=0.46; USAL: p<0.001, r2=0.53) and walking velocity (RSAL: p<0.001, r2=0.37; USAL: p<0.001, r2=0.43). In stepwise regression, walking velocity and the interaction of walking velocity with step length were removed in favor of step length. Our hypothesis is not rejected: arm swing length is more closely associated with step length than walking velocity in both shod and unshod walking conditions.

Although our pre-hominin ancestors almost certainly were climbers, most species of hominins infrequently used this ability. Recently, however people have begun to climb for recreation. With the growing popularity of rock climbing, we were interested in learning how the human body changes under these new forces. This study was designed to understand the relationship between hand proportion and hand strength in rock climbers and non-climbers. We hypothesized that rock climbers have stronger hands for their size than non-climbers. A hand dynamometer was used to test hand strength. The lengths of the carpals and metacarpals from the radial and ulnar styloid processes to the distal ends of each ray and the lengths of each digit and each phalanx were measured. In addition, the width and circumference of each hand was taken from the proximal phalanges, with the fingers resting against each other, and the circumference of each digit was measured around the proximal interphalangeal joing. We also measured the basic anthropometric variables of stature, body mass, and age and asked climbers how long they had climbed, the level of difficulty they usually climbed, and how often they climbed. Unsurprisingly, Student's t-tests revealed that the hands of men are bigger and stronger than those of women (all p's </= 0.004) and climbers are stronger than non-climbers (all p's </= 0.01). The circumference of the digits is ia significant predictor of hand strength when sex, side, and climbing status are controlled (all p's </= 0.03), with 67% of the variation in hand strength explained (r²=0.67).