Velo Clinic Bike Fit

Bike fit

Bike fit is the process of optimizing the three dimensional configuration of the cleats, seat, and handlebars for the individual cyclist.

Permissive Bike Fit

The key to the veloclinic bike fit is a concept called permissive bike fit. Permissive fit means that the goal is to configure the equipment to allow the cyclist to function within a range of motion that is biomechanically sound for the individual. Although the fitter should attempt to accommodate any biomechanical issues, the fitter should be realistic that the bike fit is unlikely to “fix” underlying biomechanical problems and understands that attempts to do so may put the cyclist at greater risk of injury and diminished performance. First and foremost, the fitter should strive to do no harm.

Background

Cyclists are at particular risk for overuse injuries with 85% percent of cyclists surveyed reporting an overuse injury from a 1 year recall period (Wilber et al. 1995). Neck pain was most frequently reported by (49%), followed by pain in the knees knees (42%), groin/buttocks (36%), hands (31%), and back (30%). Similarly, high rates of overuse injury have also been reported during multi day bicycle tours (Weiss et al, 1985, Dannenberg et al, 1996). Given this risk, the prevention of injury must be of utmost importance to the bike fitter.

Unfortunately, no bike fit intervention has yet been scientifically shown to prevent or treat overuse injuries. Instead, current recommendations are largely based on “expert opinion.” These opinions are typically most heavily influenced by personal experience or personal theories extrapolated from limited scientific evidence. Although attempts to put the scientific evidence first are made, the sober reality is that in most cases solid evidence is lacking. This lack of evidence is the reason behind the permissive bike fit concept. The permissive bike fit is essentially a do no harm approach. In it, the fitter should strive to allow the cyclist to function within a sound biomechanical range, avoid the extremes of range of motion, and do not attempt to force the cyclist into an “ideal position or movement pattern.”

Below, some of the evidence behind saddle height and cleat wedges will be discussed. The point of the discussion is to illustrate the issues with even these basic fit parameters, and why a healthy skepticism for current bike fit systems is warranted.

Saddle Height

Of the bike fit parameters, multiple authors agree that correct saddle height is not only important for injury prevention but for performance maximization as well (Obrien 1991, Asplund et al 2004, Holmes et al 1994, Shanner and Halloran 2000, Wanich 2007, Bini et al 2011). At the time of this writing, the most recent recommendations from a comprehensive review of the scientific literature recommends assessing appropriate saddle height by measuring knee angle at bottom dead center (BDC) and achieving a target range of 25-30 degrees flexion (Bini et al 2011). However, these authors concede that current recommendations are based on incomplete evidence (Bini et al 2011).

The Initial recommendations for assessing appropriate saddle height are based on adjusting saddle height to match percentages of lower extremity (LE) measurements found to maximize performance parameters (Hamley and Thomas 1967, Shennum and deVries1976, Nordeen-Snyder, 1977). Experimental evidence also demonstrates that changes in seat height relative to these LE measurements affects both tibial femoral forces as well as patellofemoral forces (Ericson and Nissell (1986 and 1987). However, a limitation of this early work is that anthropometric measurement based methods result in a wide range of kinematic responses in terms of the knee joint angle achieved at the BDC (Peveler et al, 2005). More recent studies improve upon performance maximization using a target knee angle of 25 degrees BDC as compared to the traditional method (Peveler et al 2007, and Peveler 2008, Peveler and Green 2011). The use of a target knee angle at BDC to assess appropriate seat height is supported by studies describing strong kinematic relationships between knee angle at BDC and large 4 – 10% changes in seat heights (Nordeen-Snyder 1977, Price and Donne 1997, Sanderson and Amoroso 2009).

The major commercial fit methods of SICI and BIKEFIT also primarily use the 25 -35 degree knee angle at BDC to assess saddle height as part of a whole body optimization (SICI 2007, Swift and Schoenfeldt). Cyclists undergoing a bike fit are further instructed that they may need to adjust the seat up or down by up to 1 cm or approximately plus minus 1% of seat height to accommodate for individual comfort and functional status. While any change greater than 1 cm suggests that their position is out of range and needs reassessment (SICI 2007). In this author’s experience, cyclists are unlikely to tolerate any saddle height change of more than 2 cm from an otherwise optimized position.

Although knee angle at BDC is the current standard of practice, no study has demonstrated the superiority of this measure over other parameters.  A more recent study using smaller changes of 3% produced inconsistent changes at the knee for high and  low conditions relative to a reference condition (Tamborindeguy et al, 2011).  These authors speculate that their effect at the knee may have been lost due to accommodation at another joint. This hypothesis is supported by studies showing that knee ROM, ankle plantar flexion (PF) at BDC (Nordeen-Snyder 1977, Sanderson and Amoroso 2009, Price and Donne 1997), hip rocking, and pelvic tilt (Price and Donne 1997) have all been shown to increase with increasing seat heights. Further variability  which may obscure the effect measurable at a single joint is introduced by the normal hip forward and downward translation with pedalling (Sauer et al 2007). Interestingly, a retrospective study of cyclists with knee pain showed an association with increased ankle dorsiflexion (9 degrees versus 4 degrees) but failed to find an association with knee flexion (Bailey et al 2003). Taken together these study raises doubt as to whether knee angle at BDC in isolation is the most the appropriate measure to assess 1- 2 cm (1 – 2%) changes that are typically employed during a clinical bike fit.

Cleat Wedges

One prominent theory in bike fit is that knee pain is the result of  repetitive strain from shank abduction and subsequent medial motion of the knee in response to maximal loading during the powerphase of the pedal stroke(Francis 1988, Sanner and O’Halloran 2000, Hannaford et al 1986, Asplund et al 2004, Obrien 1991, Wanich et al 2007, SICI 2007, Swift and Schoenfeldt). Varus wedges mounted under the cleat are recommended as an intervention to support the medial column, decrease shank and knee motion during the power phase, and thereby reduce knee stresses and injury risk (Francis 1988, Sanner and O’Halloran 2000, Wanich et al 2007, SICI 2007, Swift and Schoenfeldt). Due to the presence of forefoot varus in 87% of normal people (Garbalosa et al 1994), it has been suggested that the normal foot will collapse medially when called upon to act as a rigid lever in cycling and that the majority of cyclists would benefit from a  varus cleat wedge (Sanner and O’Halloran 2000, Swift and Schoenfeldt). Bike Fit Systems and Specialized both market plastic cleat wedges for this purpose (bikefit.com, specialized.com). However, the kinematic effects of the commercially available wedges have not been evaluated.

Francis (1988) first put forward the the initial theory linking foot pronation, shank abduction, and knee injury. Based on theoretical modeling, his theory states that as the foot is loaded pronation results in shank abduction during the power phase of the pedal stroke, 30 to 150 degrees (Cavanagh et al, 1988), followed by the shank returning to a neutral position in the recovery phase as the foot is unloaded and pronation is no longer a factor. The power phase shank abduction is seen clinically as medial motion of the knee towards the top tube during the down stroke. The implication is that the normal non-driving moments acting on the knee (Davis et al, 1981, Ericson et al, 1984) would be increased. Effects would then be compounded by the interaction of varus/valgus moments with axial moments to produce more knee stress than either alone (Mills et al, 1991). This theory is supported by the finding that joint moments are significantly increased by forefoot varus, and that the shank follows the expected sequence of abduction during the power phase and adduction through the recovery phase (Ruby, 1992). Unfortunately, simply allowing multi degree freedom at the pedal is not effective in reducing joint moments (Boyd et al, 1997). Instead the authors conclude that pedal parameters needed to be adjusted on an individual by individual basis. Across the board use of the varus wedge may actually be detrimental as varus pedal angulation has been shown to increase forces affecting the knee under experimental conditions (Gregersen et al 2006).  Studies on injury are limited to one very small clinical study that showed increased medial lateral knee motion to be associated with knee pain pain (Hannaford et al 1986) and  a larger retrospective study did show that a more medial knee position  was associated with injury (Bailey et al 2003).

What is not clear from available studies is whether the commercially available cleat wedges are effective in altering shank abduction during the power phase or in reducing injury risk. The only study to specifically test the effectiveness varus valgus cleat wedges found a position shift in lateral extreme of motion but no clear effect on medial most position or range of medial lateral motion of the knee (Sanderson et al 1994). It is difficult to draw firm conclusions as this study reported significant variability which may have been caused by the failure to control for major parameters of bike fit or the use of pedal strap systems which are not as secure as clipless pedal systems.

To date, no study has evaluated commercially available wedges or established that varus wedges decrease injury risk.

Know Your Limits

As a bicycle fitter you ARE providing an invaluable service in assessing the cyclists needs and abilities and making appropriate bike fit recommendations. At NO point are you diagnosing medical problems or prescribing interventions. For any suspected medical problem recommend the cyclist see a licensed medical provider.

Assessing the Cyclist

Goals and History

Identify Primary Goal: Start by finding out what is most important to the cyclist. This goal may be anything from improved performance to accommodating an injury. This goal will take priority when balancing the various aspects of the fit.

Identify Secondary Goals: This is typically the point when the cyclist will tell you they want it all. It is a good point to begin to temper unrealistic expectations. For example if the primary goal is to relieve neck pain then a secondary goal of getting more aero is not realistic.

Identify the type of cyclist: Recreational vs competitive, crit vs stage racer etc. Look to make sure that their Primary Goal is in line with the type of riding they actually do. If its not, reassess the primary goal.

Identify previous injuries or surgeries: Look specifically for issues that may cause asymmetries or limit the normal range of motion. Make sure that their physical limitations are compatible with their primary goal. If there is a conflict, reassess their primary goal.

Screen for any pain discomfort or nerve symptoms going from head to toe.

Discuss their previous fit and how they arrived at their current position.

Physical Assessment

Measure height, inseam, AC width, and weight.

Neck: Have the cyclist tilt their head back as far as comfortable.

• Limited range of motion will require a more upright position.

Shoulder: Check to make sure that the shoulders are an even height.

• Uneven height may be due to scoliosis or a leg length discrepancy both of which may cause the cyclist to sit twisted on the bike or one leg may be functionally shorter than the other. The fit may need to compromise between the two sides or may require shims under the cleat to accommodate the functionally shorter leg.

Back: Have the cyclist touch their toes (or as far as they can). Check to make sure the spine is straight and that one side of the rib cage is not more prominent than the other. Note the flexibility of the lower back.

• Curving of the spine or prominence of one side of the rib cage may be due to scoliosis or a length discrepancy.
• Poor flexibility of the lower back will require a more upright position to prevent the pelvis from rocking forward and closing the hip angle. Alternatively, if an aero position is desired the hip can be kept open with a combination of higher and more forward seat position.

PSIS (Posterior Superior Iliac Spine): Check to make sure that both sides of the pelvis are an even height.

• Uneven height may be due to scoliosis, a leg length discrepancy, or rotated pelvis.

Leg length: Have the cyclist lay on their back with their feet on the table and knees bent to 90 degrees. Check to make sure that the knees are the same height. Measure from the ASIS (Anterior Superior Iliac Spine) to the medial malleolus with the legs straight.

• A leg length discrepancy of the lower leg may be accommodated with shims under the cleat of the shorter leg.
• A discrepancy of the femur may cause the cyclist to sit twisted on the bike or require the fit to be compromised between the two sides.

Hip Flexion: With the cyclist lying on their back, bend one knee toward their chest until you see the opposite leg start to raise up off the table.

• Poor hip flexibility will require a more upright position to maintain a more open hip angle.

Hip Rotation: With the cyclist lying on their back, with the knee and hip flexed to 90 degrees, rotate the lower leg outward then inward.

• Poor range of motion may affect their ability to tolerate difference in stance width/qfactor.

Hamstring: With the cyclist lying on their back flex their knee and hip to 90 degrees. Then straighten the knee until you feel tension.

• Significant tightness may affect their knee extension at the bottom of the pedal stroke in the aero position decreasing performance.

Single Leg Squat: Have the cyclist stand on one leg with their hands on their hips. Instruct them to do a half squat. Check to see if the knee stays in line with the hip and foot, or if it corkscrews in. Also check to see if they let the opposite hip slouch downward.

• Either of these suggest poor neuromuscular control of the hip. Theoretically this may cause the knee to track in towards the top tube and put the cyclist at increased risk for knee injury.

Box Drop: Have the cyclist stand on a 30 cm high stool with feet shoulder width apart. Have them jump down with both feet and perform a maximal vertical jump with arms overhead towards an overhead target as soon as they hit the ground. Observe from the frontal view for the degree to which the knees collapse into the midline. From the sagittal plane observe for whether they land stiff legged with poor flexion at the knees.

• Either of these suggest poor neuromuscular control and may put them at risk for knee injury.

Arch: With the cyclist sitting with knees bent to 90 degrees feet shoulder width apart and shins vertical, measure the height at the navicular bone. Then have the cyclist stand and re-measure the height.

• Very flexible feet may benefit from arch support.
• Arch support to take up volume and give a more secure fit may also be useful.

Foot Rotation: While the cyclists is sitting, note the orientation of the feet (imagine a line from the heel to the second toe).

• Significant external rotation may require pedals with longer spindles to allow enough heel and ankle clearance.

Review the assessment with the cyclist.

• Go over any asymmetries explaining that the fit may have to compromise between the two sides.
• Go over any limitations in the range of motion and explain how they may affect the fit.
• For any suspected medical problems advise them to see a healthcare provider.

Set up the bike on the trainer making sure the bike is perfectly vertical and that the front and rear axles are level.

Equipment Baseline

Measure the bike.

Measure and mark cleat placement.

On the Bike Assessment

Have the cyclist warm up for as long as is practical including several all out efforts.

Instruct the cyclist to switch into their big ring and find a gear that would match a long time trial effort or hard tempo pace. Instruct the cyclist to no longer shift the rear cogs. Instead they will switch into the little ring for an easier “spin” resistance.

For dynamic assessments give the cyclist the instruction “Go ahead and spin. When you are ready shift to your big ring and settle into a steady pace.” Make your assessment after the cyclist has settled into their steady pace.

For static assessments coach the cyclist on gliding to a stop from the light spin at the BDC and cranks horizontal position and holding in the same position as they were when pedaling.

All measurements should be relative to anatomical position, ie the cyclist standing comfortably with arms at the side, palms facing forward.

Static vs Dynamic

When available dynamic measurements (from video while pedaling) are preferred over static measurements (cyclist at a stop). One study comparing static versus dynamic at different efforts the following differences (Peveler, 2011):

• Knee Angle: Static goniometer 25 deg, Camera static 28 deg, Camera dynamic low effort 35 deg, Camera dynamic max effort 33 deg.
• Foot Angle Plantar flexion from horizontal: Camera static 15 deg, Camera dynamic low effort 27, Camera dynamic max effort 22 deg.

The implication of this data is that the target range should be shifted by 5 – 10 degrees for knee angle and 7 – 12 degrees for ankle angle when using static measurements.

Similarly it is preferred to perform a bike fit on a very well warmed up if not fatigued cyclist, at moderate to high intensities, as cyclists demonstrate less plantar flexion at the ankle and less knee flexion as they increase intensity or fatigue.

Sagittal Plane Assessment  (side view)

Ankle Dorsiflexion at BDC

Measure ankle dorsiflexion at the bottom of the pedal stroke (neutral is zero, toe down is negative toe up is positive)

Metatarsals Over Spindle at Horizontal

With the cranks horizontal and the measured foot forward, assess the location of the 1st and 5th metatarsals relative to the spindle.

Knee Angle BDC

Measure the knee angle at the bottom of the pedal stroke.

Knee Over Spindle at Horizontal

In the cranks horizontal position measure the knee over spindle of the forward foot using your plumb bob.

Sacral Tilt

Measure the forward tilt of the sacrum from vertical.

Trunk Tilt

Measure the forward tilt of the trunk from vertical.

Neck Extension

Check to make sure the neck is not fully extended when the cyclist is looking up the road.

Shoulder Forward Flexion

Measure the forward flexion of the upper arm relative trunk (a superman position would be 180 degrees forward flexed)

Elbow Flexion

Measure the flexion at the elbow.

Wrist Extension

Measure the extension at the wrist.

Frontal Plane Assessment (front/back view)

Foot Rotation

Note the internal/external rotation of the foot.

Float

Check the float at BDC and cranks horizontal.

Stance Width

Note the stance width of the feet relative to the hips and thighs.

Ankle AD/ABduction

Note the ankle AD/ABduction during the power phase

Shank AD/ABduction

Note the Shank AD/ABduction during the power phase

Frontal Plane Knee Motion

Note the medial lateral Range of Motion of the knee during the pedal stroke.

Look for any jerky movements at the top and bottom of the pedal stroke.

Hand Position Width

Note the position of the hands relative to the shoulders.
Fit Adjustments

Fix anything that is way off. There is no point in spending time on small adjustments on any are if there is a large adjustment to be made elsewhere as the large adjustment is likely to shift kinematics throughout the rest of the fit;

Always ask the cyclist how they feel after each adjustment. If they feel worse after any adjustment reassess the fit as a whole.

Cleat Fore-Aft

Adjust the cleats so that the spindle splits the difference between the 1st and 5th metatarsals.

Cleat Center of Rotation

Adjust the cleat medial lateral position to bring the center of rotation under the middle of the ball of the foot.

Cleat Rotation/Float

Adjust the float and or rotation of the cleats to allow some internal and external float throughout the pedal stroke. Take out excess float.

Varus/Valgus Wedges

Consider wedges to bring the ankle AD/ABduction to neutral.

Stance Width

If possible, adjust the width of the pedals to bring the feet in line with the hips and knees.

Seat Height

Adjust the seat height for a target knee angle of 25-30 degrees with the ankle neutral plus minus 5 degrees.

Saddle Fore-Aft

With the cranks horizontal adjust saddle fore aft until the knee (tibial tubercle) is 0 – 1 cm behind the spindle.

Saddle Tilt

Set the saddle level.

Handlebar Drop and Reach

Adjust the drop and reach until the trunk is forward flexed 40 – 45 degs, with the shoulders at 90 degrees, and a 15 degree bend at the elbows.

Handlebar Rotation

Adjust handle bar tilt and hoods to bring the wrists to a neutral position.

Handlebar Drop

For sprinters consider and deep drop bar. For everyone else chose a drop shallow enough that they can achieve a 90 degree bend at the elbow in the drops.

Handlebar Width

Choose handlebar width to bring the hands in line with the shoulders.

Reassess the Entire Fit

Always check both sides. And recheck all measurements when finished. Make sure you accommodated for any issues noted in the physical assessment.

Problem Fits

Asymmetries: In general split the difference between the two sides.

Lower leg length difference: You may try shimming up to half of the difference in leg length.

Knee ankle discoordination: Recheck cleat position and knee over BDC. Excess plantar flexion maybe a cleat too far back or seat too far forward. Excess dorsiflexion may be a cleat too far forward or a seat too far back. Note that this is purely theoretical so assess the effect with some skepticism. If discoordination persists split the difference on the seat height.

Overlap between the elbows and knees: Instruct the cyclist on tilting the pelvis forward to lengthen the back. A high bar position may be needed to keep the hip angle open as the pelvis rolls forward. A wider bar can be a temporary fix.

Problem movements at the top and bottom of the pedal stroke: Consider shorter cranks

Excess medial lateral knee motion: Advise the cyclist that they may have poor neuromuscular control at the hip.

Hip drop or pulling to one side: Reassess for asymmetries, if none are found advise the cyclist that it may be a neuromuscular control issue.

Saddle Discomfort: If a trial of several saddles fails, reassess the fit, asymmetries, and neuromuscular control.

Reassessment and Documentation of the Standard Fit

On the Bike Assessment

Sagittal Plane Assessment  (side view)

Ankle Dorsiflexion at BDC

Measure ankle dorsiflexion at the bottom of the pedal stroke (neutral is zero, toe down is negative toe up is positive)

Metatarsals Over Spindle at Horizontal

With the cranks horizontal and the measured foot forward, assess the location of the 1st and 5th metatarsals relative to the spindle.

Knee Angle BDC

Measure the knee angle at the bottom of the pedal stroke.

Knee Over Spindle at Horizontal

In the cranks horizontal position measure the knee over spindle of the forward foot using your plumb bob.

Sacral Tilt

Measure the forward tilt of the sacrum from vertical.

Trunk Tilt

Measure the forward tilt of the trunk from vertical.

Neck Extension

Check to make sure the neck is not fully extended when the cyclist is looking up the road.

Shoulder Forward Flexion

Measure the forward flexion of the upper arm relative trunk (a superman position would be 180 degrees forward flexed)

Elbow Flexion

Measure the flexion at the elbow.

Wrist Extension

Measure the extension at the wrist.

Frontal Plane Assessment (front/back view)

Foot Rotation

Note the internal/external rotation of the foot.

Float

Check the float at BDC and cranks horizontal.

Stance Width

Note the stance width of the feet relative to the hips and thighs.

Ankle AD/ABduction

Note the ankle AD/ABduction during the power phase

Shank AD/ABduction

Note the Shank AD/ABduction during the power phase

Frontal Plane Knee Motion

Note the medial lateral Range of Motion of the knee during the pedal stroke.

Look for any jerky movements at the top and bottom of the pedal stroke.

Hand Position Width

Note the position of the hands relative to the shoulders.

Equipment Standard Fit

Measure the bike.

Measure and mark cleat placement.

Measure the bike.

Advise the cyclist that some time may be necessary to adjust to changes but that they should stop riding and return for any pain.

Schedule a Follow Up

No fit is complete until the cyclist has successfully accommodated to the new position without any pain or significant discomfort.
Works Cited

Asplund C, St Pierre P. Knee pain and bicycling: fitting concepts for clinicians. Phys Sportsmed. 2004 Apr;32(4):23-30.

Bailey MP, Maillardet FJ, Messenger N. Kinematics of cycling in relation to anterior knee pain and patellar tendinitis. J Sports Sci. 2003 Aug;21(8):649-57.

Bini R, Hume PA, Croft JL. Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Med. 2011 Jun 1;41(6):463-76

Boyd TF, Neptune RR, Hull ML. Pedal and knee loads using a multi-degree-of-freedom pedal platform in cycling. J Biomech. 1997 May;30(5):505-11

Cavanagh PR, Sanderson DJ, The Biomechanics of Cycling: Studies of the Pedaling Mechanics of Elite Pursuit Riders.In: E.R. Burke and M.M. Newsom, Editors, Medical and Scientific Aspects of Cycling, Human Kinetics Books, Champaign, IL (1988), pp. 3–16.

Dannenberg AL, Needle S, Mullady D, Kolodner KB. Predictors of injury among 1638 riders in a recreational long-distance bicycle tour: Cycle Across Maryland. Am J Sports Med. 1996 Nov-Dec;24(6):747-53.

Davis RR, Hull ML. Measurement of pedal loading in bicycling: II. Analysis and results. J Biomech. 1981;14(12):857-72.

Dingwell JB, Joubert JE, Diefenthaeler F, Trinity JD. Changes in muscle activity and kinematics of highly trained cyclists during fatigue. IEEE Trans Biomed Eng. 2008 Nov;55(11):2666-74.

Ericson MO, Nisell R. Patellofemoral joint forces during ergometric cycling. Phys Ther. 1987 Sep;67(9):1365-9.

Ericson MO, Nisell R. Tibiofemoral joint forces during ergometer cycling. Am J Sports Med. 1986 Jul-Aug;14(4):285-90.

Ericson, M.O., Nisell, R. and Ekholm, J., 1984. Varus and valgus loads on the knee joint during ergometer cycling. Scandinavian Journal of Sports Sciences 6, pp. 39–45.

Francis PR, Pathomechanics of the lower extremity in cycling. In: E.R. Burke and M.M. Newsom, Editors, Medical and Scientific Aspects of Cycling, Human Kinetics Books, Champaign, IL (1988), pp. 3–16.

Gregersen CS, Hull ML, Hakansson NA. How changing the inversion/eversion foot angle affects the nondriving intersegmental knee moments and the relative activation of the vastii muscles in cycling. J Biomech Eng. 2006 Jun;128(3):391-8.

Hamley EJ, Thomas V. Physiological and postural factors in the calibration of the bicycle ergometer. J Physiol. 1967 Jul;191(2):55P-56P.

Hannaford DR, Moran GT, Hlavac HF. Video analysis and treatment of overuse knee injury in cycling: a limited clinical study. Clin Podiatr Med Surg. 1986 Oct;3(4):671-8.

Holmes JC, Pruitt AL, Whalen NJ. Lower extremity overuse in bicycling. Clin Sports Med. 1994 Jan;13(1):187-205.

Mills OS, Hull ML. Rotational flexibility of the human knee due to varus/valgus and axial moments in vivo. J Biomech. 1991;24(8):673-90.

Nordeen-Snyder KS. The effect of bicycle seat height variation upon oxygen consumption and lower limb kinematics. Med Sci Sports. 1977 Summer;9(2):113-7.

O’Brien T. Lower extremity cycling biomechanics. A review and theoretical discussion. J Am Podiatr Med Assoc. 1991 Nov;81(11):585-92. Review.

Peveler WW, Shew B, Johnson S, Palmer TG. A Kinematic Comparison of Alterations to Knee and Ankle Angles from Resting Measures to Active Pedaling During a Graded Exercise Protocol. J Strength Cond Res. 2011 Dec 8.

Peveler WW, Green JM. Effects of saddle height on economy and anaerobic power in well-trained cyclists. J Strength Cond Res. 2011 Mar;25(3):629-33.

Peveler WW. Effects of saddle height on economy in cycling. J Strength Cond Res. 2008 Jul;22(4):1355-9.

Peveler WW, Pounders JD, Bishop PA. Effects of saddle height on anaerobic power production in cycling. J Strength Cond Res. 2007 Nov;21(4):1023-7.

Price D, Donne B. Effect of variation in seat tube angle at different seat heights on submaximal cycling performance in man. J Sports Sci. 1997 Aug;15(4):395-402.

Ruby P, Hull ML, Kirby KA, Jenkins DW. The effect of lower-limb anatomy on knee loads during seated cycling. J Biomech. 1992 Oct;25(10):1195-207.

Sanderson DJ, Black AH, Montgomery J. The effect of varus and valgus wedges on coronal plane knee motion during steady-rate cycling. Clin J Sports Med. 1994;4:(2):120-4.

Sanderson DJ, Amoroso AT. The influence of seat height on the mechanical function of the triceps surae muscles during steady-rate cycling. J Electromyogr Kinesiol. 2009 Dec;19(6):e465-71.

Sanner WH, O’Halloran WD. The biomechanics, etiology, and treatment of cycling injuries. J Am Podiatr Med Assoc. 2000 Jul-Aug;90(7):354-76.

Sauer JL, Potter JJ, Weisshaar CL, Ploeg HL, Thelen DG. Biodynamics. Influence of gender, power, and hand position on pelvic motion during seated cycling. Med Sci Sports Exerc. 2007 Dec;39(12):2204-11.

Shennum PL, deVries HA. The effect of saddle height on oxygen consumption during bicycle ergometer work. Med Sci Sports. 1976 Summer;8(2):119-21.

SICI Personalized Class Companion Manual 2007

Swift P, Schoenfeldt V, The Bicycle Fitting System Manual, www.bikefit.com

Umberger BR, Martin PE, Testing the planar assumption during ergometer cycling. Journal of Applied Biomechanics, 2001, 17, 55-62.

Wanich T, Hodgkins C, Columbier JA, Muraski E, Kennedy JG. Cycling injuries of the lower extremity. J Am Acad Orthop Surg. 2007 Dec;15(12):748-56.

Weiss BD. Nontraumatic injuries in amateur long distance bicyclists. Am J Sports Med. 1985 May-Jun;13(3):187-92.

Wilber CA, Holland GJ, Madison RE, Loy SF. An epidemiological analysis of overuse injuries among recreational cyclists. Int J Sports Med. 1995 Apr;16(3):201-6.

Weiss BD. Nontraumatic injuries in amateur long distance bicyclists. Am J Sports Med. 1985 May-Jun;13(3):187-92.

Wolchok JC, Hull ML, Howell SM. The effect of intersegmental knee moments on patellofemoral contact mechanics in cycling. J Biomech. 1998 Aug;31(8):677-83.