The Case for a Vibrating Saddle
The Following is a research project I recently did on Cycling Induced Erectile Dysfunction. It not only describes the mechanism by which cycling induced erectile dysfunction occurs but it also explores a possible solution to the problem
Cyclists perhaps more than other athletes have cause for concern with regards to lower extremity blood flow. Because cycling is a sport that depends largely on the aerobic energy system, must be readily available. Aerobic performance isn’t the only reason that cyclists require blood flow to the lower extremity. It is well documented that endurance cyclists often suffer from erectile dysfunction and decreased potency due to prolonged periods of decreased penile blood flow (Bressel, Reeve, Parker, & Cronin, 2007) (Spears et al., 2003). Additionally, there have been reports of severe, acute penile pain during endurance cycling events (Desai & Gingell, 1989). All of these ailments stem from hypoxia due to lack of blood flow in the lower extremity. Oxygen’s bioavailability is not only limited by the typical physiological limiting factors of like the partial pressure of oxygen ( ) (Allen & Jones, 1984) and the affinity or strength of the bond between oxygen and hemoglobin (Anderson & Kippelen, 2005). There are cycling specific mechanical limiting factors involved as well. The most well studied of these mechanical factors is that cyclists are seated on a relatively small and firm saddle. The pressure from this saddle causes compression of the lower body’s blood supply (Bressel, et al., 2007) leading to loss of blood flow to the lower extremity (Mayrovitz, Delgado, & Smith, 1998). It appears that the dimensions as well as the rigidity of the saddle combined with saddle alignment on the seat post can minimize the negative effects of this compression, increasing blood flow to the lower body (Jeong, Park, Moon, & Ryu, 2002).
One of the less studied mechanical factors contributing to change in localized blood flow is vibratory force. It has been documented that vibratory force has an effect on skeletal muscle blood flow (Kerschan-Schindl et al., 2001; Yamada et al., 2005) (Herrero et al., 2011). A team of researchers at the British Olympic Medical Institute published that they suggest two minutes of vibration platform warm up before every workout (Cardinale, Ferrari, & Quaresima, 2007). Not only is there an increase in blood flow to skeletal muscle but there is a corresponding increase in due to increased neuromuscular and metabolic activity (Rittweger et al., 2002) (Rittweger, Schiesel, & Felsenberg, 2001). Additional positive training responses that have been theorized with vibratory exercise include: soft tissue fiber realignment due to a mechanically induced massage, increases in maximal anaerobic power output and increase in maximal vertical leap. The latter two responses are believed to be caused by muscle spindle and Golgi tendon organ deactivation causing a decrease in mechanoreceptor inhibition. This in effect maximizes the stretch shortening cycle (Fallon & Macefield, 2007; Issurin, 2005) (Giszter & Kargo, 2002).
Vibration is however a double edged sword. The amount of vibration experienced, generally measured in Hz, determines the effect the vibration will have on blood flow. For example, compared to the non-vibration bouts, frequencies of 10-30 Hz increased mean blood cell velocity by approximately 33% (P<0.01) whereas 20-30 Hz increased peak blood cell velocity by approximately 27% (Lythgo, Eser, de Groot, & Galea, 2009) (Kerschan-Schindl, et al., 2001) Vibration doses smaller than 10 Hz have been shown to have very little effect and large doses of vibration have an inverse effect on blood flow. (Lythgo, et al., 2009). In the clinical setting, vibration is produced one of two ways. It is produced either through contact with a hand-held vibrating bar or rail, (Issurin & Tenenbaum, 1999) or by having the subject sit or stand on a vibrating platform (Rittweger, Beller, & Felsenberg, 2000). Currently, there are two types of vibration platforms available on the market. A platform that moves or oscillates in a vertical direction (fixed frequency and amplitude), and a platform that rotates about a fixed horizontal axis (variable frequency and amplitude) (Lythgo, et al., 2009). When trying to mimic the vibratory force experienced by a cyclist, the force plate is more practical.
In order for one to clinically test the effects of vibration on cyclist one would need to carefully mimic the types of vibration experienced by cyclists. One could mount a bicycle on a vibration platform and use a Doppler blood flow unit to measure blood flow with and without vibration. However, without the proper direction of oscillation, frequency and amplitude the results would mean nothing. Additionally, the amount of vibration experienced at the point of contact between the bicycle and the road will be significantly higher than what the rider is experiencing in the saddle. This indicates that the bicycle frame will have a huge effect on vibration absorption and transmission. As with any potential “first time” study it probably wouldn’t be perfect but it would get the ball rolling on a new idea to be researched.
ABOUT THE AUTHOR
Will Hawkins is the President of Will Hawkins Consulting LLC a company that provides cutting edge research collection and presentation packages for health and wellness companies of any size. Learn more about his company at www.willhawkinsconsulting.com or email him personally at will@willhawkinsconsulting.com.
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