Fitness Testing Assignment: Cycling

Fitness Testing Assignment: Cycling - by Linda Kuan

Contents

• Introduction
• Indications for Physiological Testing
• Features of off-road cycling
• Characteristics of a Successful off-road cyclists
• Testing procedures
• Other Testing
• Conclusion
• References

Introduction

During the last 10 years the sports of off-road (or mountain) bicycling has undergone a period of tremendous growth and development. Recent estimates indicate that there are currently over 25 million mountain bike riders in the United States compared to only 2000,000 in 1983. The number of registered off-road bicycle racers in United States is nearly equal to the number of registers road and track racers despite the fact that the national governing body for road and track cycling was found over 60 years before the governing body for off-road bicycling (Kronisch et al 1996). The 1996 summer Olympic Games included the first medal competition in cross-country off-road bicycling. The rise to this level of international competition is unprecedented for a sport so young. This review will focus on the physiological profile and monitoring of off-road cyclists who compete in cross country time trial (Pfeiffer and Kronish 1995).

Indications for Physiological Testing

Physiological testing provides an objective measure of sports performance, assesses sports specific components and identifies athletic strengths (MacDougall and Wenger 1991). It helps to plan training and develops specific rehabilitation program for the athletes (Backus and Reid 1991). The variables that are tested should be specific and relevant to the particular sports. Type of energy system and muscle action should be considered. In order to achieve a best reliability and validity of the test results, standard protocols, components that relate to the athlete's preparation, environment and equipment that are involved, should be set (MacDougall and Wenger 1991). Furthermore, the tests must be repeated or reassessed at regular intervals to determine the training effectiveness, yearly testing would be of little benefit to both athletes and coaches.

Features of off-road cycling

The cross country race is a mass-start endurance event lasting 2-3 hours (Kronisch et al 1996). They can be ridden under a wide variety of condition, on various types of terrain (ranging from unpaved roads to hiking trails) and on riding surfaces such as dirt, mud, sand and even snow (Pfeiffer and Kronisch 1995).

Characteristics of a Successful off-road cyclists

Kinanthropometry / Body Type

Kinanthropometry has been defined as an emerging scientific specialization that employs measurements to appraise human size, shape, proportion, composition, maturation and gross function and that explores problems related to growth, exercise, performance and nutrition (Ross WD and Marfell-Jones 1991).

There is no documentation in the literature reviewed specifically targeting on off-road cyclist's kinanthropometry. However, as this type of athletes need both sprint and endurance power. In 1989, McLean and Parker studied 35 elite male Australian sprint and endurance cyclists. The mean weight, thigh girth, calf girth and saddle height to lower limb length on sprint versus endurance group are 76.2 Vs 70.0kg, 57.5 Vs 54.3 cm, 37.8 Vs 36.2 cm and 98.2 Vs 92.4 cm respectively. The mesomorphic and ectomorphic ratios are 5.3 Vs 4.7 and 2.3 Vs 2.9 respectively.

In cycling, athlete's energy cost is related to two principal forces: air resistance when `traveling on flat terrain, and gravity when traveling uphill. As air resistance scales as body mass to about the 1/3 power, the difference in frontal drag (energy cost) is not in relative with VO_{2 max} (energy supply), since the mass exponent for drag (1/3) is closer to zero than that for VO_{2 max} (2/3). Therefore, if expressed relative to body mass, the frontal drag of small cyclists is considerably greater than the large cyclists. The energy cost of riding uphill also favors the large cyclist, because the weight of the bicycle represents a relatively smaller load than it does to a small cyclist (Swain 1994). Padilla et al (1999) compared the physiological capacities and performance in relation to morphotype-dependent speciality in 24 world-class cyclists, classified as flat terrain, time trial, all terrain and uphill groups. They found that uphill groups had the highest frontal area:body mass ratio and the highest maximal power output relative to body mass.

Aerobic Metabolism

The aerobic system replenishes ATP by aerobic metabolism of carbohydrate and fat. Aerobic capacity is virtually unlimited and is active in exercise of more than a few minutes duration (McArdle et al 1996). Aerobic power is the rate at which energy is provided for aerobic metabolism. It combines the abilities of pulmonary, cardiac, blood, vascular and cellular mechanisms to transport oxygen, and chemical ability of the tissues to use oxygen in breaking down fuels. Aerobic power commences after the lactic and anaerobic glycolytic pathways have been depleted. It is generally accepted that aerobic power can be determined by the maximum oxygen uptake (VO_{2 max}) or maximum heart rate (HR_max) or lactate threshold during vigorous exercises (Thoden 1991). Nichols et al (1997) indicated that power output at the lactate threshold was the best laboratory predictor of performance. Moreover, Smith et al (1999) stated that the critical power also is an indicator of aerobic fitness in trained cyclists.

Riding on various types of terrain surfaces make greater demands on the cyclists. It was shown that elite off-road cyclists possess physiological profiles that are similar to elite road cyclists in terms of maximal aerobic power, maximum heart rate and lactate threshold in both male and female groups. (Wilber et al 1997).

Several studies showed that elite cyclists had high VO_{2 max}, range from 64-76 ml.kg^-1.min^-1 (Sjogaard 1984). Thoden (1991) quoted from the Coaching Association of Canada that ranges of VO_{2 max} for international male cyclists was 56-72 ml.kg^-1.min^-1. In elite female from the United States Cycling Federation (USCF) the VO_{2 max} range was from 47.9 to 53.3 ml.kg^-1.min^-1 (Nichols et al 1997).

Anaerobic Metabolism

Off-road cycling is not a sport that required steady state work all the time. When racing on an unpaved course containing both uphill, downhill, difficult terrain and cross obstacles, anaerobic capacity is necessary. Anaerobic metabolism occurs when the level of muscular activity causes the demand for oxygen to exceed the body's ability provides it. In the absent of oxygen, the body will produce energy but at a cost. The waste product of anaerobic metabolism is lactic acid. The more intense the exercise, the faster that lactic acid is accumulated in the muscles and blood. Anaerobic metabolism is responsible for the majority of energy production in all-out efforts. The point at which lactic acid begins to quickly accumulate in the blood is known as the Lactate Threshold. Anaerobic systems can be categorized into the ATP-CP (adenosine triphosphate - creatine phosphate) and lactate systems. The ATP-CP system provides the immediate energy when exercise is commenced. While The lactate system contribute 60 to 180 seconds anaerobic energy by glycolysis to release ATP (McArdle 1996).

A Wingate anaerobic test in was held in 32 United States Cycling Federation male cyclists. Indicated that range of highest anaerobic power output was 12.39 to 14.09 W/kg and the mean power output 10.1 to 11.4 W/kg, respectively (Tanaka 1993).

Muscle fiber composition

Two types of muscle fibres can be classified by their contractile and metabolic characteristics. These are fast twitch fibres, in which energy is predominantly generated anaerobically for quick, powerful actions. The other one is slow twitch fibres, which shorten at a relatively slow speed and generate energy predominantly via aerobic metabolism (McArdle 1996).

Mackova et al in1986 found a high percentage of slow twitch muscle fibers in vastus lateralis in elite sprint cyclists. Moreover, a relatively high proportion of type I (slow twitch) muscles fibers, in quadriceps and calf, and muscle capillary density were also found in "elite-national class" cyclists by Coyle et al in 1991.

Testing procedures

Aerobic Capacity Testing

(Smith et al 1999)

VO_2max Testing

Data collection is done in the laboratory for six visits. VO_{2 max} is determined from incremental tests performed on an electronically-braked Ergoline cycle ergometer that provides constant work rates independent of pedal cadence. The ergometer is modified with dropped racing-style handlebars and a racing saddle, both similar to those uses by the cyclists on their own pedals. The seat and handlebars are adjusted to make the ergometer similar to each cyclist's own racing bicycle. These tests begin with 5 minutes warm-up at 125W. Thereafter, work rates are incremented at a rate of 25W min^-1 until the subject could not maintain a cadence of at least 50 rev min^-1. Throughout these tests, the cyclists are allowed to exercise at their preferred pedal cadence. Expired gases are analyzed on a breath-by-breath basis by a MedGraphics CPX metabolic cart. Breath-by-breath data are reduced to 15-s averages that are then used to calculate rolling 30-s averages. The highest rolling 30-s VO₂ average is taken to be VO_{2 max}.

Normative data

There are no measures of reliability or validity on aerobic test specifically for the off road cyclists in the literature. The normative data on VO_{2 max} available in the literature are lists in the national cycling teams is 65.7 to 79.3 ml.kg^-1.min^-1.

Critical Power Testing

Critical power is determined on the same modified ergometer. Athletes perform five all-out constant power tests for the incremental tests. Each test is done at a different work rate, and on different days. The first trial is performed at the highest work rate that is sustained for 30-s during the incremental test. This bout serves as a familiarization trial to reduce the practical effect known to be associated with this type of testing and the results are not used in subsequent analysis.

Work rates for the next four trials are selected to elect exhaustion in 90 to 600-s, and the order of their presentation is randomized across athletes. For each test, the cyclists warm-up for 5 minutes at 135W (female) or 150W (male) and then rest, seat on the ergometer, for 3 minutes. After the rest period, they pedale against zero resistance until a cadence of 100 rev x min^-1 is reached. At that point, the pre-selected work rate is imposed and timing begins. Athletes are allowed to select and within each exercise bout, vary their pedal cadence. Tests are terminated when a cadence of at least 50 rev x min^-1 cannot be sustained despite verbal encouragement. Time to exhaustion is recorded to the nearest second. Cyclists are not given any feedback concerning their performance until all tests have been completed.

Times to exhaustion and work rates from the four tests for each cyclist are fit to a hyperbolic model in the form:

Estimates of W_CP are expressed as W.kg^-1

Normative Data

There are no measures of reliability or validity on critical power test specifically for the off road cyclists in the literature.

Lactate threshold Testing

(Nichols et al 1997)

Although the concept of lactate threshold (LT) has been developing over at least 50 years, there is still some debate in the literature associating the metabolic characteristics of LT with respiratory events (Thoden 1991). LT is defined as the capacity to perform all out exercise for a periods of time (up to 60 seconds) depends mainly on ATP generated by the immediate and short term anaerobic energy systems (McArdle et al 1996).

Lactate threshold is determined on an electrically-braked cycle ergometer (Lode Excalibur), which is equipped with each subject's own pedals to allow each to use her own shoes. Before exercise, a baseline blood sample is obtained by finger prick, using 50µL heparanized capillary tubes and analyze immediately, induplicate, for whole blood lactate with the sport lactate analyzer. Calibrations are done immediately before testing each subject. Cyclists then warm-up for 5-10 minutes at approximately 50W at their prefer cadence. Following the warm-up, the resistance is increased to 100W and the teat is begun. The protocol consists of 25W increments every 3 minutes. At the end of each stage, the athlete stop pedaling for approximately 30 seconds while a blood sample is obtained. For each successive stage, the resistance is initially decreased to approximately 100W then increased gradually for approximately 30 seconds until the new power output is attained, at which point the clock is started for that 3-minute stage. The test is terminated one stage beyond that which elicit an abrupt rise in blood lactate greater than 1.0 mM. The athletes are fan-cooled during all exercises tests.

Anaerobic Capacity Testing

(Green and Dawson 1996)

All laboratory cycle tests are performed on a modified Monark cycle ergometer. Power output is computed every 15-s using a computer system which is interfaced with synchronized recordings of flywheel resistance, measured using a potentiometer and which generated a voltage per angular displacement of the pendulum, and the flywheel velocity which is measured from the impulses generated by the breaking of an infra-red beam by a disc, with radial cuts, attach to the hub of the flywheel. Adjustments to the configuration of the cycle ergometer can be made (at the seat, seat stem and head stem), so that it is configured according to the configuration of each cyclist's track cycle.

VO₂ measured during minute 3-4 of each power output is averaged and used to determine the submaximal VO₂ power regression for each cyclist. The power output is increased ≈22W.min^-1 to exhaustion for the determination of VO₂ peak, where exhaustion is defined as a fall in cadence of ≥3 rpm during the final work period. Using the VO₂ power regression, the power output corresponding to peak VO₂ is defined as VO₂peak (W).

Each cyclist performs three exhaustive cycle bouts, on separate occasions, at power outputs ranging (on average) between 104 and 117% VO₂peak. Following a 5 minutes warm-up at an intensity of 40% VO₂peak and 2 minutes rest, cyclists are instructed to achieve a cadance of 90 rpm, at which point the resistance is applied and timing initiated. Each cyclists is encouraged to continue cycling at a constant, predetermined power output until the power output decline to VO₂peak (W), at which moment the bout is stopped. Total work output (W_lim) during each supra- VO₂peak bout is calculated as the product of the mean power output, which is determined each 15-s, and the duration (T_lim) of the bout. The values of three W_lim - T_lim are plotted and described by the regression equation:

Where parameter a is termed Y-int (kJ; J.kg^-1) and is used as criterion work estimate of anaerobic capacity.

Normative data

Elite athletes should have the oxygen uptake from 69 to 77 ml/kg/min but there is no measure of reliability or validity on VO₂peak in the literature.

Alternative Anaerobic Capacity Testing

(Green and Dawson 1996)

Field test

All field tests are performed on an indoor 250-meter velodrome track made out of Siberian pine trimber. All cyclists are accustomed to riding on the track, using their own track bicycles that are adapted according to their discretion. Each athlete performs a 20-km time-trial (20TT), an all-out 1000m sprint (AOS) and a 2-by-2000 m ride. The 20TT is performed on one day, whereas the AOS and 2-by-2000 m are performed on the same day, separated by 60-minute recovery period, at least 48 hours after the 20TT. All performance rides are timed to the nearest 0.1s using a digital stopwatch.

20TT

After being instructed to achieve the best time possible, each cyclist completes 80 laps of the 250-m circuit and the average speed (ms^-1) for the 20TT is calculated.

2-by-2000 m

During a warm-up over 500 m the cycling speed is gradually increased to the average speed generates during the 20TT. The cyclists then completes 2000 m at the 20TT speed and continual feedback is provided so that each cyclist is within 0.5s of the time required to complete each 250m circuit. As the cyclist completes this initial 2000-m, the command "Go" is given and the cyclist then completes a 2000 m time trial in the fastest time possible, adopting an individual pacing strategy. The average speed for the maximal 2000 m time trial (TT _2000m) is calculated and the difference in speed between TT _2000m and 20TT is termed anaerobic distance (An₁) which is considered to represent anaerobic capacity.

All-out 1000 m sprint (AOS)

From a standing start, each cyclist perform an AOS, having been instructed to record the fastest time possible for the first 125 m and maintain the intensity (maximal) of effort for the remaining 875 m. accumulated time to each 125 m is recorded.

Frontal area

Each cyclist is suspended on his track bicycle whilst adopting the racing posture and wearing the clothing (including helmet) use during the track performances. The cyclist-cycle and a "metre stick" are photographed in the frontal plane from a distance of 8 m. The photograph is projected onto a draft board and the area of the tracings are determined using a Koizumi KP-90 digital planimeter. Using a "metre stick"of known area the actual frontal area (FA; m²) of the cyclist-cycle, as well as the body mass to FA ratio (BMFA), are determined.

Energy equivalent of anaerobic distance and Y-int

The metabolic energy (E_R) of cycling against air resistance is given by di Prampero as:

where v is the velocity of the cyclist and k' is a constant which is given as:

where CX is the drag coefficient [CX=0.75(7)], Ap is the projected area of the cyclist and cycle, ρ is the air density and η is the efficiency of cycling performance.

The energy equivalent for anaerobic speed (An_s; J.s^-1) is then the difference in energy expenditures between 20TT and TT_2000m and is equal to:

If An₁ = An_s.time

Then the E_R equivalent of An₁ is:

Normative data

There are no measures of reliability or validity for the field test in the literature.

Other Testing

Endurance performance testing

(Schabort et al 1997, Palmer et al 1996)

Kingcycle ergometry system

All testing is conducted on a Kingcycle ergometry system, which allows cyclists to ride on their own racing bicycles in the laboratory. After the front wheel is removed, the athlete's bicycle is attached to the ergometery system by the front fork and supported by an adjustable pillar under the bottom bracket. The bottom bracket support is used to position the rolling resistance of the rear wheel correctly on an air-braked flywheel. A photo-optic sensor monitored the velocity of the flywheel in revolutions per second (RPS), from which a computer calculated the power output (W) that would be generated by a cyclist riding at that speed on a level terrain, using the equation:

The Kingcycle is calibrated before both the incremental tests to exhaustion and the time trails.

There is no standardized fitness testing protocol available yet for in-line speed skating. The author attempts to formulate one comprising aerobic, anaerobic and flexibility tests specific to the sports, so as to evaluate the fitness of elite athletes and design appropriate training plans. Sport specificity of the tests maximizes validity and reliable testing procedures enable comparisons of the athletes in different places.

Preliminary testing

Athletes complete a progressive incremental test to exhaustion for the determination of peak oxygen consumption and peak power output on their own bicycles, where are mounted on the Kingcycle. After a 5 to 10 minutes warm-up at a self-selected intensity, the test commenced at a workload of 100W; the load was then increase by 20 W.min ^-1 until the athlete could no longer maintain the required power output. The athlete's peak power is taken as the highest average power during any 60 seconds period of the exercise test. During these incremental tests to exhaustion, athletes are requested to remain in a seated position.

During the maximal tests, athlete wears a mask covering their nose and mouth; the expired air passes through an on-line computer system attached to an automated gas analyzer. Before each test, the gas analyzer is calibrated. Analyzer outputs are processed into a computer, which calculate oxygen uptake and carbon dioxide production. During the peak oxygen consumption test and 100-km time trail, heart rate (HR) is recorded. The receiver records and stores the athlete's HR at 5 seconds intervals for incremental test and 60 seconds intervals for the time trials.

Time trials

Each athlete complete three 100-km time trials, separate by a minimum of four days and a maximum of seven days. They perform their time trials at the same time of day. Laboratory conditions remain constant during trials. Athletes are requested to perform the same type of training for the duration of the trial and to refrain from heavy physical exercise on the day before a time trial. They complete a nutritional information sheet on which they recorded the food and fluid intake for the day preceding a time trial as well as for the day on which they perform three time trials. They are then instructed to repeat this dietary regime before each subsequent trial. Only athletes who follow the standardized dietary and training protocol are included in the final analyses.

After a standardized 5-minute warm-up of easy cycling athletes commenced the 100-km time trial. To mimic the stochastic nature of cycle road races, the time trials include a series of sprints during which athletes are requested to ride "as fast as possible". there are four 1-km sprints after 10, 32, 52 and 72 km, as well as four 4-km sprints after 20, 40, 60 and 80 km. Athletes are instructed to complete the total distance in "the fastest time possible," taking into consideration the sprints that are included. Just before commencement of a sprint, the investigator gives a distance countdown and instructed the cyclist to complete the sprint in the fastest possible time as soon as they reach the specific distance at which the sprint start. Athletes view a diagram of the "course profile" which graphically illustrated where the 1-km and 4-km sprints occur before and during each ride. Instantaneous power output is recorded at each 500-m split of both 1-km and 4-km sprints to provide an estimate of the average power output for the sprint. The only feedback given to the athletes during the time trials is their elapsed distance and HR. They were not informed of the elapsed time or the times for the sprints until completion of the experiment. Throughout each trial, power output, speed and elapsed time are monitored continuously and stored in computer.

During the first time trials, subjects are allowed access to fluid and food. The quantity of fluid and food consumed during the first trial are recorded and athletes are required to repeat the same drinking/eating regimen for two subsequent rides. A fan is positioned to cool the athletes during their time trials. The average sweat rate (liters &mult; hours) is estimated by dividing average sweat loss (fluid intake + weight loss after trial) by the mean time of all athletes.

Self-evaluation Testing

Bragenzer in 1996 developed a self-evaluation test for mountain bike racer for assessing their strengths and weaknesses. He divided mountain bike racing into 5 fundamental elements:

Climbing

The ability to ride up medium or long climbs.

Endurance

The ability to hold the pace for the entire race.

Lactate Tolerance

The ability to maintain a high pace. Performing repeat hard efforts with little recovery in-between and riding at a sustained hard effort (2 minutes and over).

Technical Skills

The ability to ride single track fast, pass in single track, descend with abandon and negotiate obstacles.

Power

The ability to exert high force levels in a short period of time. In mountain biking, this translates into the ability to ride hard on short sharp hills, to accelerate quickly and sprinting.

Athletes then answer the following questions by rating their ability in each category on a scale of 1 to 10. 1-4 means really struggle, 5-7 means average and a 8-10 means excellent in this area.

Climbing	I usually pass more people on climbs than pass me.
	I can usually maintain my intensity during long climbs.
	I enjoy riding on courses with a fair amount of climbing.
	I hammer over the crest of hills.
Endurance	I usually pass more people at the end of a race than pass me.
	I do not usually "Blow-up" late in a race.
	I prefer races considered longer for my category.
	I am confident in my endurance at the start of a long race.
Lactate Tolerance	I can go hard shortly after my last hard effort.
	I can remain strong during repeat hard efforts.
	I pass more people than pass me during repeat hard efforts.
	I recover quickly after a hard effort.
	I can go hard shortly after my last hard effort.
	I can remain strong during repeat hard efforts.
	I pass more people than pass me during repeat hard efforts.
	I recover quickly after a hard effort.
Technical Skills	I am faster than most others I ride with in tight single track.
	I descend hills with abandon, only light use of brakes.
	I am comfortable riding off camber trails, tight single track turns, quick dismounts and remounts, negotiating obstacles.
	I do not fall very often.
Power	I can out sprint most of my peers.
	I can "hammer" up short steep hills.
	I drop more people than drop me on short steep climbs.
	I am usually with the leaders at the start of a race.

Conclusion

Cross- country off-road cycling is a sport requires a high aerobic and anaerobic capacity, therefore, performance measures are required to determine not only peak physiological responses but also the peak power. Five tests have been described in this paper, provide a basis from which to monitor improvements in individual performance.

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Exercise Physiology Educational Resources 1999