The information supplied regarding skeletal muscle and cardiopulmonary systems can only be beneficial if utilized effectively to monitor changes in training status and create effective training programs. Any monitoring system that is put in place should provide a physiological snapshot of an athlete’s training status. It should also be able to objectively evaluate the training load, identify the effects of a training (or even nutritional) intervention and further serve to refine training design.
The key factors that have been shown to predict triathlon performance are submaximal exercise economy and maximal velocity and power output. These factors can be evaluated for a triathlete through measures such as the blood lactate response to exercise, amount of oxygen consumed and the corresponding heart rate and rate of perceived effort (Figure 4.5, Table 4.3) that is necessary for an athlete to perform a specific workload. It is also beneficial to understand these parameters in relation to a relative percent of maximal exercise capacity. Maximal exercise capacity can be defined through maximal running and swimming velocity and power output while cycling. By understanding the relationship of perceived effort at submaximal levels in relation to the maximal velocity and power output achieved, this can provide an indication of the progress an athlete is making in adapting and improving economy.
Assessing Aerobic Economy
Aerobic capacity can best be determined through an incremental run or cycling test that is performed on a track (or set course) or in a laboratory setting. Regardless of the test chosen or the markers utilized to assess aerobic economy, they should all be able to be viewed in relation to a measure of maximal effort. Depending on the resources available and which testing parameters an athlete and coach deem beneficial, measures of oxygen consumption, work output, blood lactate and heart rate could be determined, as seen in Figure 4.6. From this information, objective markers for the blood lactate response to exercise can be determined for the aerobic threshold at 2 mmol/l-1 and the anaerobic threshold at 4 mmol/l-1 of blood lactate. The corresponding heart rate and rate of perceived effort should also be determined so that training zones can be developed, as depicted in Table 4.3. In addition, submaximal economy of the athlete can be determined by examining the amount of oxygen consumed per kilogram of body weight per minute (ml/kg/min) to perform the workload. This information can then be examined as a fractional percentage of maximal work capacity that may also include an assessment of VO2max. A set of information gathered from a pre and post test is displayed in Table 4.5.
Assessing Maximal Work Capacity
Maximal work capacity can be defined as the maximal power output or speed that can be obtained during a test to exhaustion. This measurement is typically done through an incremental step test that is performed following a short break or on the day after testing for aerobic economy. This involves an individual swimming, biking or running at faster and faster velocities until he can no longer sustain pace or a set cadence can no longer be maintained due to fatigue, as in the case of cycling. An example of a pre to post test is included in Table 4.4, indicating that training has resulted in an improved economy and maximal capacity.
Fatigue Curves In The Assessment Of Aerobic and Anerobic Training
Another means for assessing submaximal and maximal levels of work capacity is the ability of an athlete to cover two short distances (100/200 meter run; 50/100 meter swim) in which an all out bout of work is required. From this, a fatigue curve is calculated as the rate at which velocity or power output declines as the race distance increases when calculated as a percentage of a decrease in velocity or power every time the length of the performance is doubled (dallam, 108). This allows an individual to determine his potential for performance over a given distance and create training sessions that are a function of the maximal capacity the athlete has to do work. As the time decreases for the distances covered, it indicates an improvement in anaerobic power. As the rate of fatigue decreases, it is an indication that aerobic power is also potentially improving. The most indicative measure is the athlete’s perception of effort on the anaerobic and aerobic sessions that are created from the fatigue curve. As rate of perceived effort decreases, this indicates an improvement in work capacity.
Equally important to performance testing is the monitoring of an athlete’s ability to adapt to training and the training load needed to produce a given physiological response. There are three key tools that can provide the information needed to determine an athlete’s progress:
1. Recovery Score (Table 4.6)
2. Heart Rate and rPe from Criterion Training Sessions
3. Calculated Training load
In order to monitor training appropriately, a recovery score and calculated training load should be taken daily. A significant relationship has been shown between RPE and the recovery score achieved by the athlete. This becomes critical in monitoring athletes to ensure that overtraining does not occur, while also helping to determine whether the training load was significant enough to achieve the desired improvements in work capacity. The use of recovery and training load is discussed further in Chapter 10, which examines overtraining.
Monitoring the training load is an important tool that helps coaches understand how an athlete’s body is tolerating the physical training they are performing. Research has shown that individuals can have different tolerances to the same training load. Both heart rate and RPE can be utilized to calculate the training load. This is calculated as a function of training duration multiplied by the rate of perceived exertion or the average heart rate for the training bout. An example of monitoring the heart rate and rate of perceived effort for a criterion workout is provided in Table 4.7 along with the calculated training loads. Utilizing both methods, it can be seen that with adaptation to training (as indicated by decreased heart rate and rPe), the training load is decreased.
Heart Rate vs. Rate of Perceived Effort in Monitoring Training
Both heart rate and the rate of perceived effort are common tools for use in the field of endurance sport. It has been demonstrated that the rPe and heart rate response to a workload display a positive relationship that share the same pattern during training.
The use of one measure over the other in monitoring the training load and adaptations to training has been significantly debated. While heart rate has been promoted as one of the best indicators of the training load, the use of rPe has been suggested to be a more optimal factor that can be used in its place. With so much technology in today’s world, it is often forgotten to simply ask the athlete how a training session felt. When training and everything else in life is going well, the athlete can perceive a stimulus appropriately or even easier than it is intended to be. Conversely, when training or other aspects of life, such as social influences, school, weather or illness are not optimal, perception of the training stimulus can be much harder than the actual cardiovascular demand.
In general, aerobic training results in a lower heart rate and rPe for a given workload. Despite improvements in cardiovascular fitness, this relationship does not change. However, it has also been noted that heart rate alone does not regulate rPe. It has been shown that a number of psychological (mood state, stress) and physiological (breathing rate, muscular recovery rate) variables often influence the perception of effort associated with a training bout. As a result, it is most likely best to monitor both the rPe and heart rate response to training. One of the best reasons for doing this is the concept of overreaching, which is utilized with most endurance athletes to gain a training adaptation. Studies have shown that the HR to RPE relationship changes when athletes undergo periods of intense training intended to apply an overload (also known as overreaching). During a period of overreaching, higher rPes are reported for a given heart rate. Thus, the same heart rate early in a period of intense training is associated with higher rPes later on in the overreaching period. The monitoring of both heart rate and rPe for an endurance athlete should help to achieve the greatest gains possible from the training program.
About the Author
Krista Austin is an exercise physiologist and nutritionist. Her previous experience includes serving as a performance nutritionist with the English Institute of Sport where she provided services to 18 different Olympic sports and the England Cricket team. Most recently, Krista served as a physiologist with the United States Olympic Committee where she worked with multiple sports in preparation for the 2008 Olympic Games. She owns Performance & Nutrition Coaching, LLC, which provides physiological testing, nutrition and coaching education to professional and amateur athletes as well as Olympic national teams that include USA Track & Field, USA Taekwondo, USA Wrestling and USA Triathlon.
References / Recommended Readings
Dallam, George M. and Steven Jonas. Championship Triathlon Training. Champaign, IL: Human Kinetics, 2008.
McArdle, William d. et al. Exercise Physiology: Energy, Nutrition & Human Performance. 6th Edition. Baltimore, MD: Lippincott, Williams & Wilkins, 2007.
Sharkley, Brian J. and Steven E. Gaskill. Sport Physiology for Coaches. Champaign, IL: Human Kinetics, 2006.