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Curtin University
School of Physiotherapy

Swimming

Fitness Testing Assignment: Swimming - by Beate Lokken

Contents

Introduction

Swimming is a worldwide and popular sport, where you can participate at any level. Some enjoy the sport for fitness, some for recreation purposes while others compete. Competitive swimmers may cover 10,000 to 14,000 meter a day, 6 to 7 days a week. Becoming a successful swimmer takes time, skills, hard training and a love for the wet element. Different techniques are used - front crawl, butterfly, backstroke and breaststroke - and preferable distance varies. Swimming events rage from 50m (takes 22-26 sec.) and 1500m (takes 15-17 min.) Open-water or long-distance may range between 1 km (10-12 min.) to 25 km (5-6 hrs.) (Australian Swimming Inc. 1996) Shoulder problems and injuries are common in swimming, due to high repetition rate, extreme range of motion and the force required for propulsion. However, swimming is a very aerobic activity and enables people with musculoskeletal problems to train, and avoid impact forces like in closed chain activities (Zachazewski et al 1996).

The focus of this paper will first and foremost be on the physiological testing of the swimmer . A shorter overview of the sport and it's demands will be given as well.

Factors Influencing Swimming Performance

Sex Differences

Males tend to swim faster than females. Women have higher percentage of body fat than men, whereas men have more muscle weight. This results in women floating better and showing a greater swimming economy, 30 % lower energy cost than men have been reported (McArdle, Katch and Katch 1996).

Strength

Swimming power and especially upper body strength have been demonstrated to be crucial to success in sprint swimming. 86% of one's performance in a 25-m front crawl sprint result from the swimmers' strength and the ability to develop power. For the competitive distance swimmer the strength component is less. At 100, 200, and 400m, the contribution of muscular strength drops to 74, 72 and 58%, respectively. During slow, low-intensity swimming most of the muscle force is generated by slow twitch fibers. As the muscle tension requirements increase, the fast twitch fibers are incorporated. In sprint events (50-200m) demanding maximal strength, the second group of fast twitch fibers sets in. The tendency is that swimmers have higher percentage of slow twitch muscle fibers in their shoulders and particularly musculus deltoideus. However, muscle fiber composition appears not to be a deciding factor in successful competition. Swimming is performed almost totally with concentric contractions (Costill, Maglischo and Richardson 1992).

Swimming Performance

Dynamic strength is an important determinant of swimming performance. Studies have found that upper-body muscular strength and/or power output correlate highly with swim velocity over distances ranging from 23 to 400m. Also, swim and swim-specific resistance training (e.g. bio-kinetic swim bench training, reverse current hydrochannel swimming and in-water devices that the athlete push off from while swimming) improves a competitive swimmer's velocity in events up to 200m. This training can result in improved stroke mechanics, such as stroke force and distance per stroke. Research tends to conclude that stroke mechanics may be more important in determining velocity and swim success than upper body strength (Tanaka and Swensen 1998).

Energy Generation

The amount of energy required to swim is related to the intensity and strokes used. The demand for energy is reduced proportionally with the skill of the swimmer. Traditionally, monitoring the oxygen consumption during sub-maximal swimming, at speeds below those in competition has been the measure for energy use. However, swimming performance seems to be more dependent on the skill of the athlete than the VO2 max. values (Costill, Maglischo and Richardson 1992). Swimming fast is a matter of increasing propulsion while reducing the resistance of water to forward movement.

In swimming, energy is consumed both to maintain buoyancy, to generate horizontal movement through the use of arms and legs and to overcome drag forces in the water. The speed, size and shape of the swimmer and the fluid medium result in the degree of drag. The total drag force that the swimmer must encounter consists of wave, skin friction and viscous pressure drag. In comparison to running, swimmers have to use four times as much energy covering the same distance. In order to reduce the body drag, optimal technique especially of the arms is essential, and the use of wet suits have been introduced and show to decrease the body drag by 14%.

"Elite swimmers can swim a particular stroke at a given velocity with lower oxygen uptake than relatively untrained or recreational swimmers." That is, skilled swimmers use more of the energy produced per stroke to overcome drag forces. And secondly, they cover a greater distance per stroke than untrained, who use energy to move water (McArdle, Katch and Katch 1996).

Endurance

Endurance is defined as the ability to repeat muscular contractions without fatigue. Fatigue is a decline in the level of performance. The performance relates to muscular contraction and depends upon different energy sources. This again must be reflected in the duration and intensity of the contractions, and tests must seek the energy source used for these contractions (McLatchie 1993).

Aerobic Endurance

The ability of the body to support oxygen to the working muscles and to extract waste products which are transported with the bloodstream, to the airways is defined as aerobic endurance. Traditionally the Maximal Oxygen Uptake Test (VO2 max) described by Sinning in 1975, has been applied to measure aerobic capacity (McLatchie 1993).

Lactate Endurance

This is the ability of the muscle to rely on anaerobic metabolism at any given points of sub-maximal intensity of exercise. Lactic acid is the end product, and muscle fatigue will occur if it is not removed (McLatchie 1993). A study by Kesinen et al (1989) looked at different modes of lactate tests. They investigated swimming velocity, and blood lactate and heart rate responses with varying durations in separate swimming loads, and found that the most accurately evaluation of anaerobic capacity was using 2 × 100m or n × 100m modes (Keskinen, Komi and Rusko 1989).

Anaerobic Endurance

Anaerobic endurance is the ability to maintain high levels of work intensity (McLatchie 1993). The Anaerobic Threshold is the highest work intensity beyond which lactate begins to accumulate in the blood. The metabolic acidosis occuring above anaerobic threshold contribute to limitation in performance (Cellini, Vitiello, Ziglio, Martinelli, Ballarin and Concorni 1986). The aerobic training zone is differentiated into low-intensity and moderate-intensity efforts. This zone extends until the rate of lactate production exceeds the rate of removal, where the rate of lactate accumulation rises over the baseline, is termed the aerobic threshold. Once the threshold is crossed, the swimmer will not be in steady-state and cannot continue swimming at this pace for an extended period of time. At this stage hypo-aerobic fibers will dominate compared to hyper-aerobic fibers. Training over the aerobic threshold will affect the muscles ability to tolerate or buffer acid, and to remove lactate from the intra-cellular environment (Australian Swimming Inc. 1996).

Energy System Contribution

The intensity and duration of swimming determines the relative contribution of the anaerobic ATP-PC and lactate energy systems, and the aerobic energy system. "In the shortest swimming event, the 50m sprint, the relative contributions for each of the systems are: ATP-PC 65%, anaerobic glycolysis (lactate) 30% and aerobic 5%. For a 200m event the contributions are; ATP-PC 10%, anaerobic glycolysis 20% and aerobic 75-80%. Open water or long-distance events almost exclusively on the aerobic energy system" (Australian Swimming Inc. 1996).

Physiological Testing of Swimmers

The coach is an important person with his or her ability to observe and make subjective assessments of performance. But there is also a need to have objective measurements, being more valuable in giving some dimension to the result, e.g. time, distance, score (McLatchie 1993). The physiological tests are designed to follow the swimmer's physical capabilities, improvements achieved, and to assist in planning the training program (Costill, Maglischo and Richardson 1992). Total fitness consists of strength, speed, flexibility and endurance, and all of these aspects should be evaluated.

The following points should be considered before assessing fitness:

  • pre-test procedures
  • the purpose and intention of the test
  • the suitability of the test and the equipment used
  • the statistical criteria for the test
  • the use of the test results (McLatchie 1993).

The normally constant environment the swimmer trains in and the high degree of control that the coach has over the volume and intensity of training workloads, makes swimming an excellent model for applying information gained from physiological assessments (Draper et al. 1991). Information gained from testing during sub-maximal and maximal modes provides critical details for the coach to determine training loads and monitor performance improvements (Australian Swimming Inc. 1996).

The characteristics of a highly-trained swimmer are of high power and endurance. Endurance is related to the power and capacity of the aerobic energy system. This can be assessed indirectly with a graded incremental swimming test (7 × 200m step test). Power is a product of strength and speed. The use of a maximal effort 25m performance test (2 × 25m speed test) is applicable for power measurement. Muscular power may be defined as the power and capacity of the two anaerobic energy systems (ATP-PC and lactate energy systems). Speed and endurance can be estimated together in a 6 × 50m test.

Swimming is a very technical sport, and assessing the technique or stroke mechanics is important. A 7 × 50m incremental test, where stroke mechanics can be assessed from sub-maximal to maximal speeds has been suggested.

These four physiological tests have been suggested by the Australian Swimming Inc. to be performed by every swimmer. There exist several modes of testing a swimmers' fitness. Other tests that can be applied are blood testing, anthropometry, heart rate measurements, start test, turn speed test, strength tests, vertical jump test and subjective rating of effort. Three physiological tests of swimmers - one aerobic, one anaerobic and one ATP-PC test, will be described in detail later. A short description of stroke mechanics measurements will also be included (Australian Swimming Inc. 1996; Costill,Maglischo and Richardson 1992; Draper et al. 1991).

Australian Swimming Inc. 1996 is the reference for the following part.

Subject Preparation

A standardised pre-test preparation is necessary to obtain reliable and valid data. Consideration of the following factors should be made:

  • No highly stressful swimming training or weight training should be performed 24 hours before testing.
  • A normal high carbohydrate and low fat diet should be followed in the days before and on the day of testing. Avoid the intake of alcohol, caffeine and food two hours before testing. Adequate hydration is encouraged.
  • Water temperature and water quality must be checked before testing
  • A standardised warm-up of 1000-1500 m, with low-to-moderate intensity aerobic swimming, should be completed prior to testing.
  • Testing subject must be well-rested and free of illness and injury.

Aerobic Test (7 × 200m)

The aim of this test is to assess the aerobic or endurance fitness of the swimmer. Cardiovascular (heart rate) and metabolic (blood lactate) responses to increasing speeds of swimming are measured. Improvements in fitness are indicated by characteristic changes in the heart rate-velocity and lactate-velocity relationships. This has two purposes, for the prescription of training speeds and for longitudinal monitoring of changes in aerobic fitness with training. In swimming the basic interval in the various aerobic tests normally range from 100 to 400m. The longer intervals such as 300 and 400m are more likely to achieve a physiological "steady state". Intervals of 100 and 200m are more specific to the training and competitive requirements of swimmers. The 200m interval is a compromise involving both steady state achievement and speeds specific to competition levels.

Swimmers undertake a series of seven even paced 200m swims in their specialist stroke. This is performed in a five minute cycle, where the swims are graded from easy to maximal. Target times are calculated in advance and then discussed with the swimmer, coaching and testing staff. Guidelines for calculating times is as follows:

  • Determine the swimmers best 200m performance.
  • Add a 5 second differential to account for push start and training situation to estimate the time for the final swim.
  • Working in reverse order from the seventh and final swim. And add 5 seconds for each subsequent interval to establish the full test protocol.
  • All swims utilise a push start.
  • The time for each 100m is recorded.
  • Immediately upon completion of each swim, heart rate is measured immediately with an electronic heart rate meter.
  • The swimmer exits the pool after each swim and has a blood sample taken as soon as possible from the earlobe or finger tip.
  • The swimmer has a short break before commencing the next swim exactly 5 minutes after the preceding swim.
  • This cycle is continued until all seven swims have been completed.

Interpretation:

Analysis of test results should be made on a individual basis, indicated by gender and event specificity. The physiological demands also vary between each of the four strokes and within the individual medley event. Age, training background, immediate training history, injury and motivation are points justifying an individual interpretation as well.

Practically, the following aspects may assist in the interpretation of test results:

  • Has the curve moved and if so, in which direction?
  • Was the final time faster or slower than before and how does it relate to their personal best time for the 200m?
  • What were the increments in speed between each of the seven swims?
  • Were the swims completed with even or appropriate splits?
  • Were any stroke measures made? And if so are they consistent with the physiological data?
  • Was any biomechanical and/or subjective evaluation of the swimmers technique undertaken?
  • What was perception of the swimmer to their 7 × 200m test and the nature of recent training history of quality sets within the last week.

In Figure 1 (Australian Swimming Inc. 1996), a heart rate/velocity relationship derived from the 7 × 200m step test is shown. A "downwards and rightwards" shift in the curve is evidence of improvement in aerobic fitness. On the other hand, an "upwards and leftwards" shift in the curve may be evidence of deterioration in aerobic fitness.

Figure 2 shows the lactate-velocity relationship derived from the 7 × 200 step test. Computer-based analysis is used to indicate the speed at which the anaerobic threshold occurs (Australian Swimming Inc. 1996).

Speed - Endurance Test (6 × 50m)

This test assesses the ability of the swimmer to sustain near race speed over 6 × 50m intervals. It is a frequently used test in order to determine "race readiness" and as final preparation prior to competition. Indirectly, this test gives an estimation of the power and capacity of the anaerobic glycolysis system, which is the major contributor of ATP during maximal effort exercise of 1-3 minutes in duration.

  • Each swim utilises a push start. Every 50m is manual timed in a "wall-to-wall" timing process. All times are recorded to a tenth of a second.
  • Record stroke rate and count.
  • The final result is the average of the six times. The decrement be and slowest fastest and slowest time should be recorded as well.

Interpretation:

Interpretation of test results should be made on an individual basis, and compared to previous results and personal bests in the 200 and 400m events. Individual results can be compared to the group mean and range taking into account factors such as age, sex, event, distance and immediate training history.

Speed Test (2 × 25m)

The purpose of this test is to determine maximal swimming speed over 25m from a dive start and coaches use it to assess the maximal speed of a swimmer. Given the maximal intensity, but brief duration, of this test (11-15 seconds) it is assumed that performance is mostly dependent upon the ATP-PC energy system. The protocol for this test is 2 × 25m maximal effort swims.

Swimmers should use their preferred stroke, while individual medley swimmers should use butterfly (the lead-off stroke). A 25m long pool is neccessary for this test, and electronic timing is preferable. As part of the warm-up a number of dive starts and short sprints should be undertaken.

  • Each swim utilises a dive start.
  • A "wall-to-wall" timing process is used, starting timing with first observed movement and hand touch on the wall as the finish time.
  • All times to a tenth of a second is recorded.
  • Record stroke rate.
  • Some aerobic swimming is recommended between the two efforts.
  • Average of the two times is the final result for the test.

Interpretation:

The individual test results should be compared to the group mean and range taking into account the following factors: age, sex, event, distance and immediate training history. But the most valid comparison is made comparing this test's results with previous results.

Stroke Mechanics (7 × 50m)

Swimming is a technically demanding sport and much training time is devoted to refinement of a swimming technique. A series of 7 × 50m swims of progressivly increasing speed is used to establish relationships between swimming velocity( V), stroke rate (SR) and distance per stroke (DPS). This is calculated as following:

Velocity (V) = Stroke Rate (SR) × Distance Per Stroke (DPS)

Velocity (m.sec-1) = Stoke Rate (strokes.sec-1) × Distance Per Stroke (strokes.min-1)

Distance Per Stroke (DPS) = (V × 60) / SR (strokes per minute)

Interpretation:

This test gives a qualitative analysis of stroke mechanics during a series of progressively faster swims. Good technique should be maintained both at slow and fast swims.

Conclusion

Swimming is a sport that presents significant opportunities for the application of information gained from physiological testing. This paper has reviewed some of the physiological aspects connected to swimming, and the most current testing protocols used by Australian swimmers.

References

Cellini M, Vitiello P, Nagliati A, Ziglio P G, Martinelli S, Ballarin E and Conconi F (1989)
Noninvasive determination of the anaerobic threshold in swimming. International Journal of Sports Medicine 7:347-351.
Costill DL, Maglischo E.W and Richardson AB (1992)
Handbook of Sports Medicine and Science - Swimming. Blackwell Scientific Publications.
Draper J, Minikin B and Telford R (1991)
Test Methods Manual - Section Three - Swimming. National Sports Research Centre, Australian Sports Commision.
Keskinen KL, Komi PV and Rusko H (1989)
A Comparative Study of Blood Lactate tests in Swimming. International Journal of Sports Medicine 10:197-201.
McArdle W, Katch FI, Katch VL (1996)
Exercise Physiology. 4th edition, Williams and Wilkins.
McLatchie GR (1993)
Essensials of Sports Medicine. 2nd edition, Churchill Livingstone
Sports Science Advisory Group
Australian Swimming Inc. 1996, Testing Protocols 1997-2000.
Tanaka H and Swensen T (1998)
Impact of resistance training on endurance performance - A new form of cross-training? Sports Medicine 25(3):191-200.
Zachazewski J E,Magee D J and Quillen WS (1996)
Athletic Injuries and Rehabilitation. Chap. 16, W.B. Saunders Company.

Exercise Physiology Educational Resources 1998