Scientific effects of EMS training
By Dr. Kleinöder, Sports University Cologne (2010)
Static endurance: the average increase is 30.3% at an average stimulation frequency of 75 +/- 44 Hz. (1, 2, 3)
Dynamic endurance: the average increase is 41% at an average stimulation frequency of 76 Hz +/- 10 Hz (2, 4, 5, 7).
Long-term stimulation with low frequency stimulation of skeletal muscle in experiments on animals (rabbits) resulted in the development of mainly slow twitch muscle fibres with a high proportion of mitochondria (6).
- Alon, G., McCombre, S.A., Koutsantonis, S., Stumphauzer, L.J., Burgwin, K.C., Parent, M.M., & Bosworth, R.A. (1987). Comparison of the Effects of Electrical Stimulation and Exercise on Abdominal Musculature. Journal of Orthopaedic and Sports Physical Therapy, 8(12), 567-573.
- Ballantyne, E., Donne, B. (1999): Effect of neuromuscular electrical stimulation on static and dynamic abdominal strength and endurance in healthy males. Sport Science, 431.
- Kahanovitz, N., Nordin, M., Verderame, R., Parnianpour, M., Yabut, S., Viola, K., Greenidge, N., Mulvihill, M. (1987). Normal trunk muscle strength and endurance in women and the effect of exercises and electrical stimulation. Part 1: Normal endurance and trunk muscle strength in 101 women. Spine, 12 (2): 105-111.
- Kim, C. K., Takala, T. E. S., Seger, J. & Karpakka, J. (1995). Training Effects of Electrically Induced Dynamic Contractions in Human Quadriceps Muscle. Aviat Space Environ Med, 66, 251-255.
- Marqueste, T., Hug, F., Decherchi, P. Jammes, Y. (2003). Changes in neuromuscular function after training by functional electrical stimulation. Muscle Nerve 28, 181-188.
- Pette, D., Vrbova, G. (1985) Neural control of phenotypic expression in mammalian muscle fibres. Muscle Nerve 8, 676.
- Porcari, J., Miller, J., Cornwell, K., Foster, C., Gibson, M., McLean, K., Kernozek, T. (2005). The Effects of Neuromuscular Electrical Stimulation Training on Abdominal Strength, Endurance and Selected Anthropometric Measures. J of Sport Science and Medicine, 4, 66-75.
Whole body EMS: Current research and application in theory and practice
Dr. Kleinöder, Sports University Cologne
1. Possible applications
Low-frequency electrical stimulation (below 1 kHz) is used in many fields. These include medical-therapeutic applications such as prevention of muscular atrophy or quicker convalescence. It is used in other areas such as training aimed at preventing (or reducing) back pain and urinary incontinence. In amateur and professional sport, low-current EMS is also used in the areas of strength and endurance training. It can also be used for whole body or muscle relaxation and massage.
2. Forms of training
In strength training in particular, low-frequency EMS leads to an increase in voluntary contractions, which can be at a specific angle, or dynamic within a certain range of motion (ROM). In practice, those undergoing training tighten their musculature or move it simultaneously with the intensification of the electrically induced stimulation. The stimulation is of local muscles, several muscle groups or whole body EMS training. Another option is combined training where a mechanical stimulus (e.g. weight training) and low-frequency EMS are used simultaneously or successively.
3. Current level of research
Low-frequency EMS is used in the above fields with training taking various forms. The investigation by Fritzsche et al. (2010) showed for the first time the effects of low-frequency whole body EMS training in patients with cardiac insufficiency in secondary prevention efforts. The improvements to objective performance capabilities and optimisation of muscular-physiological and metabolic parameters were significant. They exceeded the results of established aerobic forms of training as part of primary and secondary cardiological rehabilitation of patients with chronic heart insufficiency (CHI). It was proven that oxygen consumption at the anaerobic threshold was increased by up to 96% (VO2at 19,39 [± 5,3] ml/kg body weight [KG] before beginning training; VO2at 24,25 [±6,34] ml/kg KG at end of training phase; p < 0,05). Diastolic blood pressure dropped significantly (psyst < 0.05; pdiast < 0.001), muscle growth amounted to up to 14% with weight constancy. The training method had a 100% acceptance rate (no attrition) and the patients experienced significantly increased performance capabilities (see Fritzsche et al. 2010).
Kemmler et al. (2009) investigated the influence of low-frequency whole body EMS training on body composition and cardiac size in older men with metabolic syndrome in accordance with IDF. The most important findings of this controlled, randomised and partially blind-tested intervention study were significant effects concerning abdominal fat, total body fat and appendicular skeletal muscle mass (ASMM) as a criterion of sarcopenia (Baumgartner et al., 1998).
Low-frequency EMS can also be effective at increasing strength in untrained people and those keen on getting fit. The average improvement in maximum isometric strength following EMS training with untrained subjects was 23.5% (Filipovic 2011). It should be emphasised that this training form does not involve high loads on the joints as with mechanical training; the frequency level can be altered incrementally and various positions can be used. Furthermore, combinations with other forms of strength training are possible. Mixed training (hypertrophy using machines) combined with EMS was shown to have the greatest effects on maximum strength (Kreuzer et al. 2006). Muscle size increased by around 10% after 8 weeks using isokinetic training (eccentric and concentric) combined with EMS (Ruther et al. 1995; Stevenson et al. 2001).
Trained athletes from various disciplines experienced increases in maximum isometric strength of between 15% and 40%, with an average of 32.6% (Filipovic et al. 2011). Using MVC (maximum voluntary contraction), competitive swimmers achieved improvements in the eccentric and concentric contractions of their latissimus dorsi and quadriceps femoris muscles and better freestyle swimming times (Pichon et al. 1995). Many authors have confirmed a positive effect on contraction speed in terms of elasticity and performance (Alon et al. 1987, Balogun et al. 1993, Cabric et al. 1987). The EMS training groups also saw the greatest gains in movement speed thus significantly increasing performance (Kleinöder 2007). A combination of classic strength training (hypertrophy) and EMS training increases both performance elements (movement speed and strength) (Cabric et al. 1987; Dörmann 2011; Mester/Kleinöder et al. 2010). This is of particular importance to those practising sports since an increase in speed is a decisive factor for success in a wide variety of disciplines.
Sprint studies showed that sprinting and jumping performance following EMS training saw gains in speed within a time period of 3 weeks in 3.1% of sports people. Brocherie et al. (2005) improvement of 4.8% in the sprint time of ice hockey players over 10m. For swimming, the time to cover 25m reduced by 1.3% and for 50m freestyle, 1.45% (Pichon et al. 1995). With combined strength training (plyometrics/EMS), Herrero et al. recorded (2006) recorded a 2.3% reduction in time needed to sprint 20m among untrained individuals. After EMS training, jumping abilities improved by between 2.3% and 19.2%; after isometric EMS training (an average of +10%); and 6.7% to 21.4% after dynamic EMS training (Babault et al. 2007, Kots et al. 1971, Maffiuletti et al. 2000, Paillard 2008). After combined EMS and classic strength training, the literature states that there was an average increase in jumping ability of 11.2±5.5% (Maffiuletti et al. 2002, Herrero et al. 2006).
Two conclusions can be drawn based on the various applications of low-frequency EMS:
EMS training improves strength, endurance and movement speed significantly. Low-frequency EMS has also been successfully used to support endurance training efforts. This form of training looks very promising for the therapy of patients with cardiac insufficiency (see Fritzsche 2010). For the body composition of older people, short low-frequency whole body EMS training sessions (approx. 45 min/week) and short intervention durations (14 weeks) showed significant effects. This leads to the conclusion that for people with low cardiac and orthopaedic capacity, GK-EMS can be an alternative to conventional training programs (see Kemmler et al. 2009).
For amateur and endurance sports, there were many improvements to fundamental static and dynamic strength parameters (maximum strength, elasticity and performance). Dynamic forms are preferable in that the controlling of intensity is made easier through movements and all the muscles are trained using the full range of movement.
Whole body EMS training is a very interesting form of low-frequency training since all the muscle groups can be trained with different emphases. It allows a great deal of flexibility in planning the training of individual muscle groups and is a time-saving form of training (15-20 minutes). Low-frequency whole body EMS training can be used to follow a range of goals (from building muscle to relaxation, see above) and is thus suitable for both amateurs and professionals.
Although a variety of different training programs led to training success, further studies are needed to further improve training choices for the various fields of application.