How Choosing The Right Bike Can Help Avoid Injury

http://www.pponline.co.uk/encyc/cycling-injury-choose-the-right-bike-to-avoid-injury-33612


To ride at your best, your bike must fit you as snugly as your cycling shorts
Australian physio Sean Fyfe explains how to steer clear of road racing pitfalls by fine-tuning your body and your machine
Cycling is more often a benign force than a cause of trouble.Because it is low impact, it provides many people who otherwise wouldstruggle to perform regular exercise, with the chance to stay healthyand active. Nevertheless, injuries do happen, and a sound knowledge,both of how the body works when cycling and of bike set-up, canminimise your likelihood of getting hurt.


Acute injury
For any competitive cyclist, to train on the road is to accept therisk of serious injury, because of the twin hazards of vehicle trafficand speed. A multitude of orthopaedic injuries occur with high-speedaccidents, but of most concern are head injuries. As a result of fatalinjuries during competitive cycling, the compulsory use of helmets hasbeen in place for a number of years at the Tour de France, except forthe finishing climb in the mountain stages.
In Australia, all cyclists (from everyday users to pro competitors)are required to wear helmets or face hefty fines. Throughout Europe, bycontrast, there is no such compulsion. Despite legislation andcampaigns promoting awareness of cyclists to other road users, acuteinjuries in cycling will always be a big concern for thoseparticipating in the on-road sport.
Chronic injury
Several studies highlight the neck and back as the main sources ofoveruse injuries. After a six- to eight-day cycling tour forrecreational cyclists, Wilber et al reported that 54.9% of females and44.2% of males presented for medical treatment with neck pain, and 30%with back pain(1). Patterson et al(2) analysed the phenomenon of‘Cyclist’s Palsy’ (numbness or tingling in the hands or fingers) inriders after a 600km bicycle ride. Of the 25 cyclists assessed, 23 hadeither movement or sensory symptoms, mostly in the hands in the ulnarnerve distribution (thumb, fourth and fifth fingers).
Wilber et al found that 85% of cyclists suffered with one or moreoveruse injury: 48.8% had neck problems, 41.7% had knee trouble, 36.1%groin and buttocks, 31.1% hands and 30.3% backs. The study also foundthat female cyclists are 1.5 times more likely than males to developneck symptoms. Although neck symptoms are the most common, in myexperience knee injuries are of more concern, as they pose a greaterlong-term risk.
Cycling biomechanics
A single pedal cycle involves a power phase from 12 o’clock to 6o’clock and a recovery phase from 6 o’clock to 12 o’clock. The powerphase delivers most of the force that generates forward momentum. Thisforce is produced via the leg extensor muscles: quadriceps, glut max,hamstring (working at the hip) and calves (working at the ankle). Therecovery phase also contributes to overall power delivered in one cycleby the upward pull of the attached shoes via the flexor muscles: hipflexors, hamstrings (working at the knee) and the calves (working atthe knee).


At 12 o’clock, the knee is flexed to 110 degrees and then extends 75degrees through the power phase to 35 degrees flexion at the beginningof the recovery phase. During the power phase the knee naturally driftsslightly inwards.
The foot pronates (rolls inwards) during the power phase, impartingan internally rotating force to the knee, increasing the stress to theinner side of the knee. The opposite happens during the recovery phasein preparation for another power push. At the bottom of the power phasethe foot should be parallel to the ground. The low and mid back have totolerate prolonged bending forwards and the upper spine prolongedextension.
Bike set-up
Correct bike set-up is crucial both to maximise performance and toavoid injuries, but very few recreational cyclists are aware of this.If you venture on to the roads on a Sunday morning, you will see drovesof cyclists with their seats set too high or their knees grosslydeviating left and right.
Bike set-up can be assisted greatly by two small pieces ofequipment: full shoe-length leg raises compensate for the slightdifferences in length commonly found between our right and left legs;and forefoot varus wedges placed between the cleat and shoe willcorrect knee alignment by allowing the foot to operate in its normalposition. Specific cycling orthotics are also commonly used.
You should also be aware of the need to adjust your bike set-up tosuit variables such as the length of race or competitive goal in orderto achieve the best balance of efficiency and comfort. In enduranceraces, riders usually opt for a slightly less aerodynamic position toimprove comfort, whereas for a short time trial, the tightest possibleaerodynamic position and lowest trunk position will deliver maximumspeed advantage.
Knee injuries
When pedalling, the largest force produced acts through the knee upto 5,000 times an hour, so it is no wonder that the slightest incorrectdistribution in load can result in a serious knee injury, includingpatellofemoral pain, chondromalacia (damage to articular cartilageunder the kneecap), inflammations of kneecap, front of thigh andhamstrings, and iliotibial band friction syndrome.
Neck and back injuries
Neck pain usually relates to the prolonged time that cyclists spendin an extended position. Neck extension with shoulders in a depressed(downwards) position increases neural tension, which can be exacerbatedif your handlebars are set too low or you fail to keep your elbowsslightly bent. Excessive or prolonged stretching of the nerves canresult in pain, numbness or tingling in the nerve distribution down theneck and arms.
To prevent the build-up of tension, you should learn to do regularforwards and sideways neck mobility and shoulder shrugs while on thebike, as well as sitting upright from time to time. You also needadequate mobility through your thoracic (mid) spine, first rib mobilityand flexibility in all the upper back and neck muscles. In recalcitrantcases, surgery may be needed to widen the nerve space.
Lower back injuries are very similar in principle to neck pain incycling, except that the aggravating position is prolonged flexion(forward bending). Muscle fatigue, chronic tension to vertebralligaments and prolonged compression to intervertebral discs can all beresponsible for ongoing backache. It is imperative that you have goodflexibility through your low back and hips.
Your pelvic position during riding is also significant. Sitting in abackwards tilted position increases low-back flexion. This can becorrected through a combination of bike set-up and proper cyclingtechnique.
As you build up your training volume, it is common to suffer fromaches in the upper, mid or lower spine, because of the lengthy periodsfor which you have to maintain a flexed trunk position. This isnormally a matter of building up your tolerance. Ensure that a sportstherapist tackles any joint stiffness or muscle tightness you aresuffering. If you intend to build up to a high weekly mileage, yourtraining should be gradual and structured.
As with all postural problems, whether on a bike or not, corestability function is crucial. Regular abdominal and back exercisesfocusing on muscle endurance should be an integral part of treatmentand prevention. Postural exercises for shoulder retractors, andespecially lower trapezius activation, are essential to minimise neckproblems. The lumbopelvic stability muscles not only have to tolerateprolonged forward bending but also to continually stabilise the lowerspine and pelvis to provide a stable platform for the majorforce-producing muscles. Core stability exercises for the lumbopelvicarea are therefore crucial in the treatment and prevention of lumbarspine pain, especially if you are increasing training volume.
Good hip flexibility matters greatly, to relieve pressure on theknee and lower spine. The hip during cycling always remains in arelatively flexed position, so chronic tightness through TFL/ITB,iliopsoas (hip flexors) and adductors (inner thigh) is very common.This can also lead to hip and groin problems. You should performregular stretches and do trigger point work on these areas. Goodflexibility through gluteals (buttocks) and hamstrings is important toenable you to sit comfortably without falling too far into a backwardspelvic tilt. Although cyclists report a relatively high incidence ofhip and groin pain, my own experience is that, as with many sports,much of this is related to the low back and pelvis.
Urogential problems
Cyclists are also at risk of urogenital problems, such as erectiledysfunction and infertility, mainly affecting male riders who put inlarge training volumes. Pudendal neuropathy (numbness or pain in thegenital or rectal area) is the most common complaint, caused bycompression of the pudendal nerve against the pubic bone. Statisticsrange from 50% to 91% of cyclists reporting symptoms(3). A change ofsaddle to one with an increased width or padding, altering the tilt ofsaddle and using increased padding in the rider’s cycling shorts mayall help to relieve the pressure.
References
1. Wilber CA, Holland GJ, Madison RE, Loy SF ‘An epidemiologicalanalysis of overuse injuries among recreational cyclists’ Int J SportsMed 1995 Apr; 16(3):201-6
2. Patterson JM, Jaggars MM, Boyer MI ‘Ulnar and Median nerve palsy inlong-distance cyclists. A prospective study’ Am J of Sports Med 2003Jul-Aug; 31(4):585-9
3. Leibovitch I, Mor Y ‘The vicious cycling: bicycling related urogenital disorders’ Eur Urol 2005 Mar; 47(3):277-86