Isokinetic leg press for testing and training the lower limbs in closed kinetic chain
An innovative, ballistic control behaviour allows achieving higher accelerations and thus faster movement by pre-calculation of the movement to be expected. This results in significant reduction of the influence of the moments of inertia. In ballistic mode, higher speeds of movement or a defined speed for longer times, respectively, can be carried out isokinetically. The ballistic mode optimizes training and testing with functional and realistic movements and loads.
Patients with little strength are often unable to move individual segments of their bodies without assistance. This means that active compensation for these static weight influences is required over the entire motion amplitude. While the movement is being performed, the dynamometer can continuously reduce the external forces or even compensate for them completely; this produces a „gravity-free“’ situation for the patient where every movement can be performed with minimal expenditure of force.
The exceedingly high sampling rate of 4000 Hz ensures extremely precise control of the dynamometer and reduces unwanted jitter (temporal frequency deviation in the control system) to a minimum below the perception threshold. Thanks to the play-free drive train, no play can be felt during movement reversal, which is particularly relevant for highly dynamic movements (such as throwing). This also allows practice of unique movement sequences such as combination of continuous-passive movement (CPM) with concentric or eccentric loading.
The constant offset of 12 milliseconds at full sampling rate (4000 Hz) allows precise, easy and reliable synchronisation of the signals.
The continuously adjustable mechanical movement stops limit the range of movement directly at the dynamometer. In addition, the position of the movement stops is tracked by the system and constantly matched against the selected movement pattern. Thus, the software redundantly prevents exceedance of the movement amplitude.
In CON-TREX® systems, the dynamometer is moved to the patient. The flexible dynamometer head allows precise and very close adjustment of the rotary axis of the dynamometer in relation to the joint axis.
The products of the wide adapter range are made of high-strength stainless steel, combining maximum torsional stiffness with the lowest possible mass moment of inertia. Adjustment is continuous and time-saving thanks to a sophisticated and reliable clamping mechanism.
Individually customisable reports with a variety of presentation options and diagrams, and function for export as a PDF document. The export of the measurement data as an ASCII file allows further processing in other programs.
The isokinetic CON-TREX® WS was developed to imitate motions of working environments, sports and everyday domestic life. In order to be able to follow the unique and often extremely complex patterns of movement, the height of the dynamometer can be electronically adjusted from down close to the ground to up over the patient‘s head. For realistic simulation of unusual movements the CON-TREX® WS can be rotated and swivelled. The possibility of reproducible assessment of work capacity is thus provided. Various movements from the everyday life of a craftsman (such as screwing, lifting objects, butting levers or sawing) can be simulated and trained. In addition to preparing for difficult working conditions (such as working overhead), CON-TREX® WS can be used to compose a specific and highly effective muscular workout. In practice, a minimum working area of only 2 x 2 meters is sufficient.
The human kinetics software allows easy separation of databases, thereby enabling different internal departments or scientific areas within the same facility to work independently. The presentation of the numerous report designs can be customised. Export to other data processing programs is done easily via the ASCII interface. Anonymisation of the data for scientific work is easily possible.
The detailed online help provides direct notes on the current menu item or the operation being performed, with images and graphics. Above all, the detailed information on the numerous movement performances clarifies both the positioning of the subject / patient and the use of the required adapters.
CON-TREX® can be used in early diagnostic and preventative therapy for injuries to the musculoskeletal system in out-patient rehabilitation and in the clinic. It is also used in scientific research and performance optimisation and facilitates the careful and specific analysis of problems and thus the highly efficient training of top athletes.
CON-TREX® machines are suited to measurement and analysis thanks to the high levels of precision and are thus especially well-suited to scientific use. In training and therapy, they aim to improve muscle capabilities (in both the strength and stamina areas) as well as sensorimotor skills. Thanks to its versatile measuring capabilities and the intuitive exercise software, CON-TREX® is excellently suited to the following applications:
Orthopaedic rehabilitation and traumatology:
CON-TREX® enables the early diagnosis and prevention of damages or injuries to the musculoskeletal system in out-patient rehabilitation and in clinical use.
Diagnosis and rehabilitation of musculoskeletal deficiencies
Muscular disbalances can disrupt the ideal sequence of movements and may have damaging effects on the joints or, depending on the type of sport, can even be desirable or required. CON-TREX® helps to record, detect and analyse these disbalances. In addition, CON-TREX® machines can be used to efficiently eliminate muscular disbalances. One particular benefit is in the fact that the tested movement can be trained at the same time.
CON-TREX® machines can be used in the area of geriatric rehabilitation after artificial joint replacement in particular. Even at very low available muscular strength patients can actively train and improve their muscularity at a sensible speed of motion. This means that the loss of strength is kept to a minimum and the mobility of the joints either remains the same or is improved.
When performance is diminished for neurological reasons, for example, after a brain injury or a stroke, rehabilitation work focuses on restoring coordination and control of the work done by the muscles. The German Society for Neurology demands the early functional mobilisation of patients who are after having suffered a stroke. CON-TREX® is suited to this task thanks to its exercise and training function in a continuously passive motion mode: The affected patient's limb is moved by CON-TREX® while the patient can simultaneously attempt to autonomously control and move the limb. CON-TREX® simultaneously visualises the ongoing performance of the patient, that is, training can be followed in real-time on the monitor and even the smallest of advances is immediately reproduced on the screen. This adds to the patient's motivation to increase the effectiveness of the rehabilitation through their active cooperation. This can only be achieved to a limited extent using "classic" training methods. Bio-feedback training, especially with a submaximal load, not only enables efficient correction of muscular deficiencies, but is also an excellent method of improving coordination abilities.
Optimised performance in competitive sports:
CON-TREX® machines are used in competitive sport, most of all when it comes to objectively evaluating physique and optimising the progression of training of competitive and top-level athletes. Various strength tests which can be carried out at regular intervals provide both trainers and athletes with precise feedback on the effectiveness of their training methods. Within the framework of motion analyses for the optimisation of motion sequences specific to particular sports, precise problem analyses can also be generated using combined EMG evaluations. When rehabilitating top athletes after injuries, CON-TREX® machines facilitate highly efficient training sessions and contribute towards the sensible use of the injury period.
Science and research:
Thanks to the high levels of precision of CON-TREX® machines, the objective evaluation of every patient at the highest validity rates possible is given. CON-TREX® archives all relevant system parameters which could be of importance to scientific evaluation. In addition, the unique ballistic mode ensures the smooth execution of both motion sequence and measurement. This active gravity compensation facilitates both absolute and relative observation of the values. When used in science and research, the CON-TREX® machines set previously unequalled high standards in regard to accuracy of measurement and reproducibility of the collected parameters.
Caruso J., Brown L.E., Tufano J.J. (2012): The reproducibility of isokinetic dynamometry data. Isokinet Exerc Sci 20:239–53. doi:10.3233/IES-2012-0477.
Cotte T., Ferret J.M. (2003): Comparative study of two isokinetic dynamometers: CYBEX NORM vs. CON-TREX® MJ. IOS Press Isokinetics and Exercise Science 11(1), 37-43.
Guilhem G., Giroux C., Couturier A., Maffiuletti N.A. (2014): Validity of trunk extensor and flexor torque measurements using isokinetic dynamometry. J Electromyogr Kinesiol http://dx.doi.org/10.1016/j.jelekin.2014.07.006.
Maffiuletti N.A., Bizzini M., Desbrosses K., Babault N., Munziner U. (2007): Reliability of knee extension and flexion measurements using the Con-Trex isokinetic dynamometer. Clin Physiol Funct Imaging 27, 346-353.
Müller S., Baur H., König T., Hirschmüller A., Mayer F. (2007): Reproducibility of isokinetic single- and multi-joint strength measurements in healthy and injured athletes. Isokinetics and Exercise Science 15, 295-302.
Müller S., Mayer P., Baur H., Mayer F. (2011): Higher velocities in isokinetic dynamometry: A pilot study of new test mode with active compensation of inertia. IOS Press, Isokinetics and Exercise Science 19, 63–70 63, DOI 10.3233/IES20110398.
Müller S., Stoll J., Müller J., Mayer F. (2012): Validity of isokinetic trunk measurements with respect to healthy adults, athletes and low back pain patients. Isokinet Exerc Sci 20, 255–66. doi:10.3233/IES-2012-00482.
Müller J., Müller S., Stoll J., Fröhlich K., Baur H., Mayer F. (2014): Reproducibility of maximum isokinetic trunk strength testing in healthy adolescent athletes. Sports Orthop. Traumatol. 30, 229–237.
Baray A.L., Philippot R., Farizon F., Boyer B., Edouard P. (2014): Assessment of joint position sense deficit, muscular impairment and postural disorder following hemi-Castaing ankle ligamentoplasty. Orthop Traumatol Surg Res 100 (6 Suppl), 271-4. doi:10.1016/j.otsr.2014.02.014. Epub 2014 Aug 22.
Baray A.L., Philippot R., Neri T., Farizon F., Edouard P. (2016): The Hemi-Castaing ligamentoplasty for chronic lateral ankle instability does not modify proprioceptive, muscular and posturographic parameters. 24(4), 1108-15. doi:10.1007/s00167-015-3793-3.
Baur H., Müller S., Hirschmüller A., Huber G., Mayer F. (2006): Reactivity, stability and strength performance capacity in motor sports. Br J Sports Med 40, 906-911.
Baur H., Müller S., Pilz F., Mayer P., Mayer F. (2010): Trunk extensor and flexor strength of long-distance race car drivers and physically active controls. J Sports Sci 28: 1183–1187.
Edouard P., Castells J., Calmels P., Roche F., Degache F. (2010): Cardiovascular and metabolic responses during isokinetic shoulder rotators strength testing in healthy subjects. ISSN 0959-3020/10 Isokinetics and Exercise Science 18, 23–29 23. doi:10.3233/IES-2010-0363 IOS Press 23-29.
Edouard P., Bankolé C., Calmels P., Beguin L., Degache F. (2013): Isokinetic rotator muscles fatigue in glenohumeral joint instability before and after Latarjet surgery: a pilot prospective study. Scand J Med Sci Sports 23(2), 74-80. doi:10.1111/sms.12011. Epub 2012 Nov 1.
Edouard P., Degache F., Oullion R., Plessis J.Y., Gleizes-Cervera S., Calmels P. (2013): Shoulder strength imbalances as injury risk in handball. Int J Sports Med 34(7), 654-60. doi:10.1055/s-0032-1312587. Epub 2013 Feb 26.
Francis P., Toomey C., Mc Cormack W., Lyons M., Jakeman P. (2016): Measurement of maximal isometric torque and muscle quality of the knee extensors and flexors in healthy 50- to 70-year-old women. Clin Physiol Funct Imaging 28, n/a–n/a. doi:10.1111/cpf.12332.
Hirschmüller A., Konstantinidis L., Baur H., Müller S., Mehlhorn A., Kontermann J., Grosse U., Südkamp N.P., Helwig P. (2011): Do changes in dynamic plantar pressure distribution, strength capacity and postural control after intra-articular calcaneal fracture correlate with clinical and radiological outcome? Injury 42, 1135–43. doi:10.1016/j.injury.2010.09.040.
Hirschmüller A., Andres T., Schoch W., Baur H., Konstantinidis L., Südkamp N.P., Niemeyer P., (2017): Quadriceps Strength in Patients With Isolated Cartilage Defects of the Knee: Results of Isokinetic Strength Measurements and Their Correlation With Clinical and Functional Results. Orthopaedic Journal of Sports Medicine 5:232596711770372. doi:10.1177/2325967117703726.
Liebensteiner M.C., Platzer H.P., Burtscher M., Hanser F., Raschner C. (2012): The effect of gender on force, muscle activity, and frontal plane knee alignment during maximum eccentric leg-press exercise. Knee Surg Sports Traumatol Arthrosc 20, 510–516. DOI 10.1007/s00167-011-1567-0.
Mueller J., Mueller S., Stoll J., Baur H., Mayer F. (2014): Trunk Extensor and Flexor Strength Capacity in Healthy Young Elite Athletes Aged 11–15 Years. Journal of Strength and Conditioning Research 28, 1328–34. doi:10.1519/JSC.0000000000000280.
Mueller S., Mueller J., Stoll J., Cassel M., Hirschmüller A., Mayer F. (2017): Back Pain in Adolescent Athletes: Results of a Biomechanical Screening. SMIO 01, E16–E22. doi:10.1055/s-0042-122713.
Mueller S., Mueller J., Stoll J., Engel T., Mayer F. (2017): Back pain risk factors in adolescent athletes: suitability of a biomechanical screening tool? British Journal of Sports Medicine 51, 364–5. doi:10.1136/bjsports-2016-097372.205.
Rahm S., Spross C., Gerber F., Farshad M., Buck F.M., Espinosa N. (2013): Operative treatment of chronic irreparable Achilles tendon ruptures with large flexor hallucis longus tendon transfers. Foot Ankle Int 34(8), 1100-10. doi:10.1177/1071100713487725. Epub 2013 Apr 26.