Pultruded fiberglass rods enhance athletic training apparatus
Photo credit: Flexi-StiX
For sports that require jumping or running, athletic training will likely involve dynamic movements that not only strengthen certain leg muscles, but activate fast-twitch muscle fibers.
Gordon Brown, President of Flexi-StiX LLC (Anderson, SC, USA), began his career in the textile industry as an industrial engineer with Burlington Industries in 1968. Since then he has held various positions in textile and composites companies. While working for the pultrusion company Morrison Molded Fiber Glass Co. (now Strongwell, Bristol, Virginia, USA), Brown became interested in the use of pultruded fiberglass rods in gym equipment , for their ability to add “flexible resistance,” he says. Fiberglass pultruded rods and bars provide tailored flex resistance with the flexibility needed to train an athlete’s muscles.
Inspired by fiberglass composite pole vaults, exercise equipment and the Bodyblade – an oscillating therapy and exercise bar developed in the 1990s by physical therapist Bruce Hymanson – Brown developed and patented a collapsible bar comprising rectangular rods of pultruded fiberglass/epoxy contained within a flexible PVC tube.
Brown explains that in his patented process, he inserts long, thin fiberglass/epoxy-pultruded bars of rectangular cross-section into a round tube, where they fit securely but loosely into the tube. When the device is bent or shaken during a training exercise, the flexible tube oscillates around the fiberglass rod. “Having the fiberglass shapes float inside the extruded tube allows the shapes to automatically orient themselves so that they bend around the main axis of the fiberglass pultruded shape when the product is bent,” he said. The rectangular section is essential for the rods to stay in place, he adds. “When dealing with products that flex or wobble, you have to be concerned about flex fatigue, and one way to achieve sufficient flex stiffness with good flex fatigue resistance is to use a rectangular shape,” he explains.
Photo credit: C.W.
In 2003 Brown started Flexi-StiX LLC to market and sell his inventions. The first commercial iteration of Brown’s design was licensed for Body bar inc. (Louisville, Colorado, USA), a company that manufactures bars for step aerobics, as a more flexible alternative to the company’s traditional steel bars. In 2012, Brown developed and marketed the tsunami bar with Clemson University (SC, USA) strength and conditioning coach David Abernathy. Developed in multiple sizes and resistance levels, the Tsunami Bar is marketed as a flexible bar that can be weighted using traditional disc weights and used in the same way as traditional steel bars.
Brown says, “I consider myself an expert in using composite apparatus to help train athletes to perform at a higher level. I learned from exercise physiologists that to create “explosive force” or Powerful in athletes, a controlled amount of additional resistance must be provided to the muscles that are trained during rapid movements.
See the Furman University (Greenville, SC, US) Instagram post below for a demonstration of how to use Jump Sticks:
In 2020, Brown developed his newest invention, the Jump Stick, which is a version of his flexible composite bar specifically used to activate fast-twitch muscle fibers in the legs so athletes can practice jumping higher or to move with greater agility. The athlete holds a Jump Stick in each hand while jumping, using the weight and resistance of the bar to train the leg muscles to pull faster.
Each Jump Stick, which weighs less than five pounds, when bent into a U shape is said to produce approximately 40 pounds of bending resistance. Brown says that if an athlete jumps up and down five times as fast as he can putting as much force into the ground as he can using the Jump Sticks, he will jump between 1 and 5 inches higher during his jump. next standing vertical jump. For Jump Sticks, one to three pultruded fiberglass shapes, all 0.187 inches thick and 0.5 inches wide, and about half an inch shorter than the tube itself , fit into the tube depending on the weight and stiffness needed. Flexi-StiX uses Glasforms pultruded rods supplied by Avient (formerly PolyOne, Avon Lake, Ohio, USA). “In use, all shapes move to bend around their main axis when the device is bent as the athlete jumps quickly. If you are familiar with leaf springs on an automobile, my use of several fiberglass pultruded shapes is similar,” says Brown.
To test and validate the Jump Sticks, Brown worked with local high schools and coaches and athletes from Furman University (Greenville, SC, US). Currently, the product is available in two sizes, 35 inches and weighing 2 pounds with the addition of rubber weights, and 49 inches with 4 pounds of weight. The shorter, lighter version is ideal for young athletes, and the longer, heavier version is designed for college or professional athletes.