Resonance in Human Walking Economy: How Natural Is It?

Locomotion and movement economy are cornerstone topics in movement science. Modeling the leg as a hybrid mass-spring pendulum shows walking economy should be optimized when stride frequency matches the resonant frequency of the limb. Human walking is described as self-optimizing because mean preferred (PSF) and modeled resonant (RSF) stride frequencies usually are statistically equivalent, but this depiction may not be fully justified. Purpose: To more thoroughly examine the self-optimization characterization and the consequences of obligating use of the RSF. Methods: Forty-seven individuals of diverse statures completed 3 consecutive days of preferred walking trials on a treadmill where stride rate, stride length, walking speed, heart rate and walking economy measures were made under steady state heart rate conditions. Anthropometric measures were taken to build a hybrid model of the leg and model the RSF. Reliability across days was evaluated via repeated measures analysis of variance (ANOVA) and intra-class correlation (á=.05) and correlations were calculated for PSF and RSF. A separate sample of 20 participants walked under 3 conditions, (1) completely preferred; (2) at the original preferred speed using the RSF; and (3) with the option to establish a new preferred speed while using the RSF. Results: Gait characteristics were fundamentally reliable across days and the correlation between PSF and RSF was weak (8% explained variance). Walking economy improved 14% when using the RSF and allowed to self-select the speed / stride length used at that cadence. Conclusions: The results raised slight questions about current self-optimization presumptions and further emphasized the role of resonance in walking economyFaculty Sponsor: Dr. Philip K. Scho

Treatment of Headache in the ED: Haloperidol in the Acute setting (THE-HA Study)

Background: Headache is the 4th leading complaint of patients presenting to the emergency department (ED). Treatment for headache varies, but patients are typically treated with a combination of nonsteroidal anti-inflammatory drugs (NSAIDs), metoclopramide, and diphenhydramine. Study Objective: To evaluate the efficacy and safety of a reduced dose of haloperidol in the treatment of undifferentiated headache in the ED. Materials and Methods: A Randomized, double-blind, placebo-controlled trial performed at a single teaching hospital in Kalamazoo, Michigan. Patients who presented to the ED with benign headache between the ages of 13 and 55 were enrolled. Between October 2015 and June 2016, the ED enrolled and randomized 118 patients. Five patients were excluded due to early discharge, leaving 113 patients in the final analysis cohort. Of this cohort, 60 patients were randomized to receive placebo and 53 received 2.5 mg of haloperidol, both administered intravenously. Individuals who did not exhibit a fifty percent reduction of pain at 60 minutes received 30 mg of intravenous (IV) ketorolac as rescue. Akathisia was treated with 25 mg of IV diphenhydramine if indicated. The primary outcome measure was a reduction of pain from baseline based on a ten-point visual analog scale (VAS). Pain scores were reassessed at 30, 60 and 90 minutes from baseline. Patients were evaluated for adverse events at each data collection point and follow-up was conducted 24 hours post discharge from the ED. QT measurement was performed at baseline and at discharge. Results: Of the 113 patients included, 53 patients received haloperidol versus 60 receiving placebo. Statistical analyses on demographic data were not statistically different with the exception of a greater proportion of males in the haloperidol group compared to the control. Patients in the haloperidol group reported a -2.60 reduction in VAS at 30 minutes versus -1.27 in the control group. Later time points showed a -4.76 reduction in VAS at 60 minutes in the haloperidol group versus -1.87 in the control group. Rescue treatment with ketorolac was required in 78.3% in the control group versus 32.1% in the haloperidol group. The most common adverse events were anxiety, nausea, vomiting and restlessness. At discharge, no patients in the haloperidol group were found to have any lengthening of their QT interval. Conclusion: This study presents new data that a low dose IV haloperidol is a safe and effective initial approach to managing benign headache in the ED