A study to compare strengths of cadaveric tendon repairs with round-bodied and cutting needles

This human cadaver study investigated whether flexor tendon repairs performed with round-bodied needles had a higher risk of pull-out compared with those performed with cutting needles. Forty human cadaver tendons were repaired (20 with each type of needle), subjected to tensile traction testing and evaluated by failure load and mode of failure. The average failure load was 50 N (SD 13 N) for tendons repaired with round-bodied needles, compared with 49 N (SD 16 N) for tendons repaired with cutting needles. Round-bodied needles resulted in more suture pull-out (18 out of 20 tendons) than cutting needles (6 out of 20 tendons). We found no differences in failure load, but significant differences in the mode of failure between round-bodied and cutting needles when used for cadaveric flexor tendon repair.

Increasing Running Shoe Traction can Enhance Performance

The outsole of a running shoe must provide enough traction for the athlete to avoid slipping during running. What is unknown is whether there is any point to designing running shoe outsoles with traction above this minimum required traction. The purpose of this study was to investigate whether performance could be enhanced by increasing the outsole traction of a running shoe. A commercially available running shoe (Control) was compared against the same shoe model with the outsole modified with a higher traction rubber (High Traction). The available traction of each shoe was measured with a traction testing system. Twenty male athletes completed a maximal effort timed running course in both shoes on two different surfaces. When wearing the Control running shoe, the athletes were able to complete the course on an asphalt road surface at maximal effort without slipping. When completing the same course wearing the High Traction shoe, the subjects were able to perform the course even faster. Therefore, the results show that the role of running shoe outsole traction is not to merely provide adequate traction to avoid large scale slips, but can also help athletes enhance performance of high-traction tasks such as accelerations and changes in direction.

Comparative Studies in Traction Concepts

The interaction between tires and soft soils is a complex process that has not yet been fully understood. Attempts to create analytical models which realistically simulate these interactions have proven to be exceedingly time consuming for each tire model and have achieved only limited success. Thus, the exploration and evaluation of traction concepts by analytical means is impractical. This paper posits that significantly more reliable, rapid, and cost effective development is achieved through the prototyping and experimental evaluation of traction concepts. Here, three traction prototypes are developed and evaluated by undergraduate teams in the course of an academic semester. These concepts explore the performance of grousers, inverted geometry (dimples), and cellular materials respectively using a wheel endurance and soft-soil traction testing system at Clemson University. Each concept is tested at different acceleration rates from 0–10km/h and at different loads while measuring the slip between the tire and soil surfaces. The results of experimental evaluation indicate that cellular materials present a unique slip profile which is superior to that of the two other purely geometric concepts studied. The worst performance was seen on the inverse geometry concept which presented a behavior of steadily increasing slip with respect to wheel velocity regardless of acceleration. Grousers also presented this behavior but only at higher accelerations. This suggests that not only that prototyping is preferable, but that traditional soft-soil traction approaches may be in error.

Forensic Engineering Use Of Walkway Traction Testing

Pedestrian Fall Events Are Frequently Linked To Slippery Walkway Surfaces. Friction Is The Measured Quantity At Issue In Traction Testing Which Has Been Conducted Using Various Devices For Over 80 Years. The Various Available Devices (Called Tribometers) Each Have Their Advocates, Resulting In A Certain Amount Of Controversy. Robust Analysis Of Walkway Traction Requires An Understanding Of Individual Tribometer Characteristics And Knowledge Of Potential Limitations In The Ability To Test Certain Surfaces & Contaminants. It Is Also Necessary To Understand The Status Of Relevant Traction Testing Standards And To Be Familiar With Current Research Which Links Tribometer And Human Subject Testing To Provide Required Friction Values For Safe Pedestrian Ambulation.