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MADISON - During a long bike ride, it's not unusual for cyclists to experience hand or finger numbness, a very common condition known as cyclist's palsy. The condition ranges from mild tingling to, sometimes, long-term nerve damage and hand muscle atrophy over time.
A team of University of Wisconsin-Madison engineers has scientifically measured hand pressure during cycling and studied potential solutions to reduce that pressure, which can cause problems like cyclist's palsy, a condition that Wisconsin-based Trek Cycling Corp. estimates affects as much as 70 percent of cyclists. Trek has incorporated the UW-Madison findings into the design of a new Bontrager cycling glove that it will release this winter.
Mechanical engineering associate professors Heidi-Lynn Ploeg and Darryl Thelen led the UW-Madison team, which studied the effects of seven glove (or no glove) types and three hand positions on the hands of 36 experienced cyclists. Ploeg and Thelen found that much of the pressure on cyclists' hands is concentrated over the ulnar nerve and gloves with proper padding density, thickness and placement are able to reduce pressure over this region of the hand. Also, the team found certain hand positions can alleviate pressure, such as holding the part of the brake attached to the handlebars, a position known as "hoods."
The glove project, which began in fall 2008, is the second time Ploeg and Trek have partnered to understand how cyclists' bodies interact with bikes. Prior to the glove study, Ploeg and Trek evaluated how bike saddle design affects pressure. That project determined saddle design should be based on a rider's size and sex, and Trek introduced new ergonomic products based on the research.
When Trek decided to update its glove line, it quickly decided to again approach UW-Madison. "There are a lot of claims out there about cycling gloves. We wanted to see what was real," says Trek's Bontrager product manager, Jennifer Retzlaff. "Based on the success Trek had with UW during the saddle project, we decided to go ahead with a similar process so we would have hard scientific evidence that we were doing the right thing for cyclists."
The UW-Madison team worked with a German-based novel GmbH to find a pressure mat that was the right size and could be worn under a glove while a subject rode a bike. The team also performed laser scanning to relate the measurements from the mat's more than 200 sensors to the subject's hand anatomy. This determined that pressure concentrations were located over the three muscles below the pinky finger that make up the hypothenar region of the hand, which is the source of cyclist's palsy.
Ploeg, a biomechanics expert and an avid cyclist, says partnering with Trek was a unique opportunity to look at the potential of cycling research. "Cycling is a really accessible activity for people. It's something a lot of people can do and could use to improve their health," she says.
Cycling also is a relatively simple model for biomechanical analysis. "Cycling is repetitive and predictable, so there are some basic questions you can ask about human motion and neuromuscular control of motion by using cycling as a model," Ploeg says.
For Trek, the benefits of gaining a scientific understanding of hand pressure outweighed the risk that the study could have determined cycling gloves don't actually make a difference. "We approached it from a point of truly trying to learn what happens at the intersection of the hand and the bike," says Trek designer Ryan Gallagher.
Bontrager brand manager Tom Kuefler says the study evokes Trek's Midwest roots. "We're a Wisconsin company, and one of our core company values is to have unyielding integrity and honesty in everything we do. Having a scientific understanding of how glove design affects pressure on a cyclist's hands allows us to create better products," he says.
In addition to Ploeg and Thelen, the UW-Madison team included School of Medicine and Public Health clinical assistant professor Mark Timmerman, mechanical engineering Ph.D. student Josh Slane, undergraduate students Caitlyn Collins and Yvonne Schumacher, and Memorial High School student Jane Lee.