The cycling shoe is unique among athletic shoes and serves to integrate the foot and lower extremity with the crank arm and drivetrain of the bike by way of the pedal. The typical cleated cycling shoe is designed around an adducted last which is comparable to a 2–4 in. dress heel. The typical European designed cycling shoe also tends to be narrower than their domestic counter parts. However, the anatomy of a typical triathlon cycling shoe is standard and can be subdivided into four primary areas of importance:

Similar to running shoes, comfort and performance can be enhanced when triathletes carefully select training and racing shoes.

Toe break angle and stack height are two variables unique to cycling shoes. Toe break angle is the degree of rise of the forefoot of the shoe. Shoes with greater toe break angles may permit the cyclist to generate greater power during the power and recovery phases of cycling and ease muscular fatigue. A moderate toe break angle will permit the downward force applied by the extending lower extremity to the crank arm to remain closer to perpendicular to the crank arm, thereby achieving a more efficient transfer of force to rotational torque as the ankle plantarflexes through late power phase. However, high toe break angles will preload the plantar fascia and potentially increasing its intrinsic tension through excessive tightening of windlast mechanism increasing the potential for plantar (fascia) forefoot pain. Stack height of a cycling shoe may vary by brand, model, and design. It is the thickness of the sole of the shoe at the cleat attachment point measured in millimeters. By maintaining the foot close to the pedal axle power transfer during both the power and the recovery phases of cycling will be enhanced. Higher stack heights are more typical of molded thermoplastic nylon soles which require greater thickness to achieve sole rigidity. Carbon and carbon composite soles achieve equal to greater sole rigidity while maintaining low stack heights and can improve the overall shoe pedal–drivetrain efficiency. High stack heights may adversely impact the triathlete during run transitions in cycling shoes. During the brief run through transition, a high stack height can potentially dorsiflex the foot at the ankle increasing the concentric tension imparted upon the Achilles tendon and calf muscles. High stack heights can also increase the potential for lateral instability of the foot and ankle during run transitions.

Numerous guidelines for the categorization of running shoes have been circulated in the popular press. The following list of general categories is the most widely accepted and used for running shoes:

Considerable overlap may exist; shoe authorities and manufactures may disagree on the assignment of a shoe to a category. However, based upon long-standing use and acceptance by the public this system provides a good starting point for the selection of an optimal training and racing shoe for the triathlete.

Shoes for cushioning represent designs which emphasize cushioning and flexibility. These shoes typically possess a uniform density midsole, limited shoe stabilizing add-in features, and an outsole which promotes flexibility while maintaining good traction with the support surface. These shoes promote an efficient running gait and rely on normal lower extremity and foot biomechanics. These shoes are best suited for the efficient lightweight runner with a normal to high-arched foot who demonstrates normal lower extremity biomechanics. The neutral shoe represents a design which promotes adequate cushioning, flexibility with the addition of limited stabilizing features. These shoes are best worn by a lightweight runner who exhibits normal lower extremity biomechanics. Stability running shoes are designed with the intent to augment the natural stability of the foot through all phases of gait. These shoes emphasize adequate cushioning and forefoot flexibility and enhanced motion controlling properties. These shoes are best worn by lightweight through normal weight runners with normal through moderately abnormal lower extremity biomechanics. Runners with normal foot biomechanics may elect to use this shoe to promote greater stability, especially during runs when fatigue influences normal running gait. Motion control shoes are intended to promote a maximum level of support and influence under the most extreme levels of excessive pronation of the foot during all phases of the running gait cycle. These shoes are better suited for runners with low-arched or a pes planus foot type and work well for individuals competing in the heavy weight class. These shoes are generally poorly suited for the lightweight runner due to the presence of very firm midsole materials which can promote excessive resistance to the normal foot function. Racing shoes represent a very special classification of running shoe; these shoes are intended to be lightweight and generally are poorly suited for the average triathlete.

Finding the best training or racing shoe can be a formidable task. Numerous options exist; each shoe type and category is rich with near equal choices and each manufacture provides proprietary technology designed to enhance each run or ride; considerable overlap exists between manufacturers promoting shoes within any given category. The process of selecting a suitable running shoe can be enhanced by following a few simple rules:

A few moments spent examining a new shoe can prevent the selection of a poorly constructed, designed, or possibly mismatched training or racing shoe.

To achieve an optimal fit, match the shape of the foot to the shoe last shape; fit an adducted foot and or cavus foot type to a curve-lasted shoe, a low/flat-arched pes planus foot type to a straight-lasted shoe, and fit the normal foot type to a combination-lasted shoe. The modern running shoe is built around a neutral position which places the heel counter of the shoe perpendicular to the support surface. Evaluate a shoe for neutral position on a flat and level surface; heel counters which are inverted or everted will impose an abnormal influence upon the foot through heel contact and can adversely effect the intended influence of foot orthoses throughout the gait cycle. Unnecessarily stiff or too proximal forefoot flexibility will increase the resistance to heel off leading to excessive momentary loads to the metatarsophalangeal joints and to the distal expansion of the plantar fascia. Midfoot torsional stability permits the rearfoot and forefoot to function independently in the frontal plain, yet provide resistance to sagittal and transverse plain movement. Excessive midfoot flexibility may increase the risks of overuse injuries linked to excessive and prolonged midstance and propulsive phase pronation of the foot. Heel counter stiffness relates to the rigidity or compressibility of the shoes rearfoot. Shoes with greater heel counter stiffness promote enhanced rearfoot stability at heel contact through midstance phases of gait. Heel counters with greater stiffness also provide a stabilizing influence to foot orthoses; enhancing orthoses heel cup influences directly to the foot and by providing a firm barrier against which the foot orthoses rearfoot posting may establish a predictable seating and a surface from which to establish leverage. Shoe upper (vamp and quarter) side-to-side stability is critical to maintaining the foot directly over the outsole and midsole of the shoe during all phases of running gait and under all circumstances of running surface and terrain. Excess shoe upper side-to-side movement will increase the risk of both chronic overuse injuries and even acute inversion (foot and ankle) injuries. Stable shoe uppers are well reinforced and exhibit minimal transverse plain (side-to-side) shift when stressed. Securing the shoe to the foot is the role of the shoe lacing system; important features for the triathlete to consider include adequate variability to the lacing system to suit the specific needs of the athlete, suitability of the lacing system to the introduction of elastic or speed laces, and a design which avoids pressure points across the dorsum of the foot. Triathletes train year round and under a wide variety of conditions. In many regions of the world training may occur on slippery, wet, or icy conditions providing far less than optimal footing and traction. Careful inspection of outsole traction design patterns and outsole composition should be considered when selecting a training/racing shoe. Bill Bowerman, Coach Oregon State University, was the first to introduce the waffle sole pattern which has given rise to a myriad of outsole designs. While waffle-type soles provided superb combination of flexibility and traction; its lack of surface area compromises its stability and traction on firm and slippery or icy surfaces. Mixed high–low horizontal and diagonal patterns with crisp edges and traction and flex channels will provide better traction on firm surfaces with poor traction but will become unsuitable when traction is required such as when running on trails. The firmness of the outsole will also influence flexibility, traction, and wear potential. Hard firm materials promote the greatest durability but may sacrifice traction, cushion, and flexibility while softer materials sacrifice durability. Most modern training shoes will accept foot orthoses; however, special considerations should be made for the suitability of the shoe to accommodate a foot orthoses. Shoes which will eventually be used with a foot orthoses should provide a versatile lacing system, alternatives to secure the rearfoot snuggly, adequately deep heel cup and rear quarter, removable sock liner, flat stable insole, torsional stability, minimal instep cut out, and adequate width and length. Many times the introduction of a foot orthoses will increase the shoe size need (length) by one half size.

When carefully selected, a well-designed cycling shoe can shave seconds off an athlete’s finishing time and help the athlete to avoid injury. While overlap exists between running shoes and cycling shoes, such as last shape, neutral position, heel counter rigidity, and orthoses suitability, features unique to cycling shoes should be considered separately when selecting a cycling shoe:

The heart of every cycling shoe is a comfortable upper that snugly fits to the foot without contributing to pressure points, promotes good air flow through the shoe, and minimizes irritating internal seams. The triathlete should carefully examine the closure system for durability, ease of use, adjustability, and security. A stable sole is critical for the transfer of power from the lower extremity to the bike drivetrain; examine the cycling shoe for longitudinal and torsional stability. The sole should resist torsional flexion when a twisting force is applied especially during climbing and sprinting out of the saddle. While longitudinal flexion will ease running and walking through transitions zones too much flexion will sacrifice power transfer to the bicycle. Avoid cycling shoes that permit longitudinal flexion. Examine the shoe sole for proper cleat anchoring; a secure and adjustable anchoring site/system that fits to the intended pedal system is important to optimize power transfer, comfort, and minimize the potential for overuse injuries of the foot, knee, and hip. Examine the shoe sole for toe break angle and stack height; avoid excessive toe break angles which may enhance power transfer when pushing big gears but are not well suited for spinning in lower gears as is more typical to triathlon training and racing. Avoid excessive stack height, by keeping the pedal/cleat close to the shoe sole power transfer from the lower extremity to the bicycle drivetrain will be improved through all phases of riding.

No discussion of cycling shoes should go without a brief discussion of pedal systems. Pedals serve as the link between the cycling shoe and the crank arms of the bicycle. Careful selection of a proper pedal system has been shown to reduce overuse injuries of the knee. Float is a terminology used to describe the ability of the cyclists foot to rotate in the transverse plain or for the shoe to be adjusted upon the pedal (in-toed or out-toed) to suite the structural/anatomical needs of the cyclists. Clip-type pedals into which the forefoot slips allow the foot to move side-to-side and to rotate in the transverse plane with limited resistance. However, this method of securing the foot to the pedal is inefficient and permits a significant loss of power during both the power and the recovery phases of the pedal cycle. Clipless pedals secure the foot directly to the pedal minimizing the loss of power during both phases of the pedaling cycle. Some clipless pedal systems permit the rider to adjust the angle of float necessary to achieve a neutral position of the lower leg (patella) to the pedal axle. Three basic systems are available and include unrestricted float, limited float, and fixed float angle; each permit transverse plane (in-toe or out-toe) adjustments of the shoe/cleat position in relationship to the pedal axle and when properly adjusted can reduce lower extremity overuse injuries resulting from transverse plane malalignment of the lower extremity. These pedal systems are especially effective when applied to reduce chronic overuse and torque strain exerted upon the knee and hip during the power phase of cycling. Common overuse injuries such as patellofemoral pain syndrome and iliotibial band syndrome will often respond favorably to a properly fit pedal system.

The primary role of athletic socks is to protect the exercising foot from excess moisture accumulations, such as perspiration or extrinsic moisture (rain and spray/mist stations), promote padding, accommodate anatomical irregularities, reduce pressure, and reduce friction and torque forces. The military has long held to the recommendation of a two-sock system to minimize the occurrence of friction blisters. The military has exerted a considerable effort to evaluate socks and boots in an effort to identify the best boot–sock system. Herring and Richie observed that sock fiber-type and sock construction properties could be linked to the frequency, size, and severity of friction blisters among runners, and with careful sock fiber and construction selection the frequency of potentially disabling friction blisters could be reduced. More recent evidence from the Office of Navel Research has associated the development of more serious lower extremity injuries including overuse injuries with military recruits suffering from frequent friction blister events. Based upon these data alone the triathlete should carefully examine the intrinsic and extrinsic circumstances associated with running and cycling in an effort to select an optimal sock to reduce the risk of skin and thereby other musculoskeletal injuries.

The human foot exhibits a significant potential to produce perspiration. The human foot possesses approximately 3300 eccrine sweat glands per square inch or approximately 200,000 eccrine sweat glands per foot. At rest the human foot is capable of producing approximately 1/4 cup of sweat in a 12-h period. With vigorous activities, such as running and cycling, the triathletes’ foot may produce vastly more perspiration in the same 12 h dramatically increasing the potential risk for friction blisters. This risk can be reduced by selecting socks which contain a high percent of CoolMax fibers; these synthetic polyester fibers are specially designed to minimize moisture regain (absorption) and possess a four-channel cross section which enhances the wicking potential of the sock. Polypropylene is another frequently encountered synthetic sock fiber used to manage moisture; however, due to these fibers’ extreme hydrophobic tendencies it can trap excess moisture on the skin and limit the wicking of moisture away from the skin and increase the risk of friction blisters. Synthetic acrylic fibers are also excellent fibers from which to make athletic socks. These fibers offer the distinct advantage of a soft feel, comfort, durability, and excellent wearability, but due to the fibers’ low moisture regain (absorption) and limited moisture wicking abilities they may leave the foot feeling slightly damp. Merino wool is an excellent natural fiber from which athletic socks are knit. Unfortunately, these wool fibers exhibit moderately high extensibility (stretch), poor overall elasticity (return to original shape during vigorous use), and moderately high moisture regain (absorption). The best sock would benefit from the properties of CoolMax, Merino wool, and acrylic blended together into one sock. This sock would exhibit the thermal benefit and moisture absorption properties of wool, the moisture wicking and low moisture regain properties of CoolMax, and the wearability and durability of acrylic.