Ergometry
With various methods of ergometry , physical performance must be precisely specified, repeated under the same conditions and the results assessed objectively. The word ergometry is a compound word from the ancient Greek words ἔργον érgon , German 'work' and μέτρον métron , German ' measure ' , 'scale' and means work measurement . With various ergometers, the individual physical performance can be documented as part of a performance diagnosis using step or endurance tests as well as cross-sectional and longitudinal examinations. Ergometry devices are also used as training aids in sport as well as in medical practice and rehabilitation. Similar devices have also found widespread use as home trainers or movement trainers in the private sector.
history
The Englishman Francis Lowndes patented an exercise machine called Gymnasticon at the end of the 18th century. The device was developed primarily for joint exercise. The first attempts with a braked crank handle were carried out by Max von Pettenkofer in 1866 and by Charles Richet in 1886 .
The first ergometers were developed in Germany at the end of the 19th century. The Hessian doctor C. Speck created an apparatus in 1883 for the purpose of exact dosing and precise reproducibility of physical work. It was a crank ergometer with work standing up. Four years later, the Viennese doctor Gustav Gaertner presented a mechanically braked ergometer on this basis. This device called Ergostat was later produced several times.
Nathan Zuntz developed the world's first treadmill in 1889. As a professor of physiology at the Agricultural University in Berlin, he initially only intended it for examinations with horses. In the period that followed, he and his colleagues created more ergometers for measurements on people.
The construction of the first bicycle ergometer is attributed to the French physiologist Elisée Bouny in 1896. He fitted a jacked up bicycle with no front wheel with a mechanical brake on the rear wheel.
In 1899, the Americans Wilbur O. Atwater and Francis G. Benedict had test subjects do a dosed work on a bicycle ergometer. This drove a dynamo, the power generation and heating of which served as a measure of the work performed. This working group also developed the first electromagnetic brake on a bicycle ergometer in 1912 .
Today there is an almost unmistakable range of the most varied devices for the individual application areas on the market.
Rotary crank ergometers manufactured in series
Pedal work for prisoners
The first bicycle ergometer in the world
Bicycle ergometer developed by Voigt and Zuntz in Berlin around 1900
Bicycle ergometry with examination of gas metabolism
Devices and designs
Exercise bike
Bicycle ergometers, also known as exercise bikes , are available in different versions. You don't use your own bike for the test or for training, as is the case with the training rollers . A distinction is made between the normal sitting position (upright) and the so-called recumbent bikes (recumbent ergometers), in which the legs are stretched forward. Recumbent bikes are said to be gentler on the spine thanks to the support function that comes from a seat / reclining shell. You originally come from the rehabilitation sector. Brake systems used are eddy current brakes , band brakes , magnetic brakes , electromotive brakes (electric generator brakes ), wind turbines and water brakes (can only be used with Aquacycling ).
The spin bike, also called speed bike , is a special form . This so-called indoor cycling bike features a large flywheel. The disc has a diameter of 65 centimeters and weighs around 20 kilograms. It creates a moment of inertia that is missing when the bike is stationary and provides a more realistic riding experience. In addition, the effort required when accelerating is significantly higher, which also adapts better to the specific sequence of movements and makes the movement more economical.
Treadmill
Today's users of treadmills include medical facilities (hospitals, rehabilitation centers, medical and physiotherapy practices, institutes at universities), sports clubs, biomechanics institutes, orthopedic shoe shops, running shops, Olympic training centers, universities, fire service training centers, NASA , test facilities and training rooms by the police and armed forces, fitness studios and also private users.
Safety standards for treadmills are EN 957-1 and EN 957-6. For medical treadmills, IEC 60601-1 and the Machinery Directive also apply . Today, treadmill ergometers are mainly equipped with a motor drive. Most treadmills have a running table with a sliding plate. There are two shafts in front of and behind the moving table. A running belt is stretched between the shafts and the running table.
The test subject moves on the running table and adapts to the adjustable speeds of the running belt. The walking table is usually mounted on damping elements so that the walking table gives way a little with every step so that the surface does not become too hard for the test person. A lifting element can be used to lift the entire treadmill frame, including the table, at the front, thereby simulating an incline angle for uphill runs. Some treadmills also reverse the direction of rotation of the running belt for the purpose of downhill loads. Most of the treadmills for professional use in the fitness sector have running table sizes of approx. 150 cm in length and 50 cm in width, a speed range of approx. 0… 20 km / h and an incline angle of 0… 20%.
Larger and more stable treadmills are necessary for athletes . Sprinters can briefly reach speeds of up to 45 km / h with some weight relief and must therefore have a large walking table up to 300 cm long and 100 cm wide. If the workload is high and the risk of falling is increased, a fall arrest device is required to prevent the test person or patient from falling. This fall arrest device is usually implemented by a safety bar to which a line with an electrical switch is attached. A chest harness catches the test person in the event of a fall and switches off the running belt.
In therapy centers , treadmills are also used with built-in seats on the left and right for therapists who then e.g. B. move the legs of a stroke patient in order to simulate walking movements and to relearn how to walk.
Oversized treadmills are also used for cyclists with speeds of up to 80 km / h, for wheelchair users and, in special designs with thick running belts, also for cross-country skiing and biathletes who complete training and tests on a running table up to sizes of 450 × 300 cm² with roller-ski equipment .
Special ergometers
As an ergometer, a device that is as similar to a sport as possible (bicycle ergometer, treadmill ergometer , rowing ergometer , paddle ergometer , swimming channel, etc.) is used. These are also used as training aids. In addition, hand crank ergometers are used for special loads on the arms and the muscles of the shoulder girdle .
In the scientific field, NASA uses ergometers in airplanes during parabolic flights to study the movement of astronauts in weightlessness or under reduced gravity. After returning from space missions, space travelers are rehabilitated again on instrumented treadmills with force measuring plates built into the running table and introduced to a natural gait pattern on earth.
Areas of application
Performance test
In competitive sports , in sports medicine and in occupational medicine , ergometry is used to determine the performance level of the person examined. The results are used for further planning of the training or the stress. The various examination and exercise programs are specified by the sports associations or by occupational medical diagnostic programs. A general distinction can be made between standard and step tests. While in the former, a load may be specified in several stages, which is terminated after completion, in stage tests the performance is gradually increased (e.g. every 3 minutes increase in performance by 50 watts on the bicycle ergometer or exercise ) until it is exhausted (exhausted ) . Increase in treadmill speed by 0.5 m / s).
Leisure area
Ergometers have also become widespread in the leisure and fitness sectors. The weather-independent training, the computer control with various training programs and the possibility of modern ergometers to connect them to the computer ensure a wide range of possible uses. By connecting to a PC or a mobile device, it is possible to record and compare performance data. Furthermore, cross trainers and movement trainers have found widespread use.
There are legally prescribed distinguishing features between ergometers and exercise bikes . Ergometers display the current output in watts as well as the converted energy in kJ (alternatively in the outdated unit kcal ) and must adhere to certain measurement tolerances. If this is not the case, it is a (usually cheaper) "exercise bike" which, according to DIN EN 957-1 / 5, may not display the power in watts, but an energy display in kJ or kcal is permitted.
medicine
In the medical field, ergometry helps in the detection and assessment of the progression of heart and lung diseases and is an important tool for risk and prognosis assessment . Rehabilitation doctors use them to be able to give specific therapy recommendations, to check the effectiveness of measures and to carry out specific exercises.
In cardiorespiratory diagnostics, ergometry is combined with measuring systems for lung function (spiroergometry / ergospirometry).
For patients in German-speaking countries, mainly bicycle ergometers, less often treadmill ergometers, are used. In Anglo-American countries, the exercise treadmill test (ETT) or graded exercise stress test (GXT) is usually completed on the treadmill or on standardized climbing levels . Movement therapy devices are primarily used in neurology .
indication
Ergometry is recommended for patients with a medium pretest probability . Patients with a high pre-test probability and typical symptoms should primarily be recommended invasive or radiological procedures. Patients with a low pretest probability often have a false positive result.
execution
Many different exercise protocols are common, depending on the objective of the investigation and the subject. In medicine, a gradual exercise over nine to twelve minutes is carried out either according to a scheme proposed by the WHO or by the Federal Committee for Competitive Sports (BAL). In addition, there has been a protocol in Austria that can be calculated based on the individual expected value since 2008. The WHO recommends starting with 25 or 50 watts and increasing by 25 watts after every two minutes, the BAL recommends starting with 50 or 100 watts and increasing by 50 watts every three minutes. The maximum achievable pulse rate is calculated using the formula 220 minus years of life (age) . An exertion upon reaching the lower standard deviation adopted (maximum frequency minus about 10-12 beats per minute), for example for a 60-year-old ie at a frequency of about 150 / min. The Bruce protocol is usually used for an ergometric test on the treadmill .
Contraindications
In the case of an existing acute myocardial infarction or unstable angina pectoris , no stress test may be carried out, and certain other manifest cardiovascular diseases are also contraindications : severe hypertension at rest, carditis , heart failure , severe cardiac valve defects, dangerous cardiac arrhythmias at rest or aortic aneurysm .
Termination criteria
The test must be terminated if the ECG shows deep ST segment depressions or elevations, angina pectoris symptoms, an increase in blood pressure above 220 mmHg, a drop in blood pressure below the baseline value or ventricular arrhythmias.
Findings
A at rest
B at 75 watts
C at 100 watts
D at 125 watts
The maximum load capacity is determined in absolute terms in watts and relative to the age, gender and weight-related target performance or target working capacity. It allows conclusions to be drawn about the life expectancy ( prognosis ) and the risk of planned operations in patients with heart disease . The certainty of proof of a coronary stenosis in need of treatment is around 70 percent. Myocardial scintigraphy or coronary angiography have a higher diagnostic certainty .
Angina pectoris and a decrease in the ST segment on the ECG are the typical findings in coronary artery disease . The main criterion for an abnormal response is a horizontal or descending ST segment depression of 0.10 mV . It is usually an expression of a stress-induced circulatory disorder ( ischemia ) of the heart muscle. ECG changes that are already present at rest and the influence of some drugs (e.g. beta blockers and digitalis ) limit the informative value of ergometry for this question.
Certain cardiac arrhythmias that begin or become more pronounced under stress can also be an indication of a circulatory disorder.
See also
literature
- K.-H. Arndt: Sports medicine in medical practice . JA Barth, Heidelberg / Leipzig 1998, ISBN 3-335-00542-2 .
- HH Dickhuth (ed.): Sports medicine . Ärzteverlag, Cologne 2007, ISBN 978-3-7691-0472-1 .
- W. Hollmann, K. Tittel: History of the German sports medicine . Druckhaus, Gera 2008, ISBN 978-3-9811758-2-0 .
- H. Löllgen, E. Erdmann, AK Gitt: Ergometry - Stress tests in clinic and practice . 3. Edition. Springer, 2009, ISBN 978-3-642-05384-9 .
Web links
- http://www.trainingandracingwithapowermeter.com/2010/04/brief-history-of-training-and-racing_1025.html
- http://www.leistungsstest.info/Ergospirometrie.html
- http://leitlinien.dgk.org/images/pdf/leitlinien_volltext/2000-05_ergometry.pdf
- http://www.oegth.at/wcms/ftp//o/oegth.at/uploads/praxisleitlinienergometriea2008.pdf
Individual evidence
- ↑ Wildor Hollmann: Sports medicine . Schattauer, Stuttgart 2000, ISBN 3-7945-1672-9 , p. 333 .
- ↑ Photo: RIA Novosti archive, image # 555848 / Vitaliy Arutjunov / CC-BY-SA 3.0
- ↑ Haas in MMW, 5 2013 p. 26
- ↑ J Kardiol: practice guideline stress test ; 2008; 15 (Suppl A): 3-17
