Galileo^® Training – the Muscle-Bone Relation 

During our lifetime bone adapts to the daily maximum forces, which act upon it. These maximum forces cause small, elastic deformations of the bone (typically about 0.1% to 0.2% of its length). If these deformations exceed a certain threshold, it stimulates bone growth, but if this deformation is below a second (lower) threshold, the bone is resorbed. Examples of this effect are the bone loss in astronauts during long-term space flights and in old people when they adopt a sedentary lifestyle. Both will suffer from a function-related bone loss, which can be easily confused with a pathological osteoporosis. Selective Galileo Training can compensate for the functional bone loss.

Resulting maximum forces during everyday movements

Somewhat surprisingly, the maximum forces acting on bones are not created directly by external influences, but by the muscles themselves.

This becomes clear when one takes the typical leverage ratios in the body into account. A good example is the ankle. A healthy person hopping on one leg (like when using a skipping rope) generates a force, which is roughly equivalent to 3.5 times the body weight.  Mainly the calf muscle, obviously, generates this force.

If we consider that the ratio between the distance from the forefoot to the ankle and the distance from the ankle to the Achilles tendon that is attached to the calf muscle, is approximately 3:1, the calf muscles must generate a force that corresponds to 10.5 times body weight in order to produce a force of 3.5 times the body weight at the forefoot (ground reaction force). Since the calf muscle requires an abutment, this force must therefore also act on the bone. So during everyday movements a force of 14 times body weight or more can act easily on the lower leg bones. For a person with a body mass of 80 kg this would correspond to over one ton, i.e., the weight of a small car.

For comparison: Hitting the ground with straight leg, a force equal to typically 2 or 3 times body weight is generated. In this case, however, there is no leverage, so that the same force acts on the bone. This simple example shows that, normally, the contribution of muscle forces on bone is significantly larger than external forces.

The peak forces described above in a healthy fit subject result in a deformation of bone between 1000 µStrain and 2000 µStrain. In a tibia length (shin-bone length) of about 40 cm this corresponds to a deformation between 0.4 mm and 0.8 mm. This shows the magnitude of the impact of everyday movements in bone strength.

This fact makes it clear that appropriate daily exercise is needed to avoid bone resorption. Targeted Galileo Training can help prevent this bone loss.

J Electromyogr Kinesiol. 2012 Feb;22(1):21-30. doi: 10.1016/j.jelekin.2011.09.009. Epub 2011 Oct

Resistive vibration exercise during bed-rest reduces motor control changes in the lumbo-pelvic musculature.

Belavý DL, Wilson SJ, Armbrecht G, Rittweger J, Felsenberg D, Richardson CA.

Source:  Charité Universitätsmedzin Berlin, Zentrum für Muskel- und Knochenforschung, Hindenburgdamm 30, 12200 Berlin, Germany. belavy@gmail.com

Abstract

Purpose:  To understand the effects of a resistive vibration exercise (RVE) countermeasure on changes in lumbo-pelvic muscle motor control during prolonged bed-rest, 20 male subjects took part in the Berlin Bed-Rest Study (in 2003-2005) and were randomised to a RVE group or an inactive control group.

Method:  Surface electromyographic signals recorded from five superficial lumbo-pelvic muscles during a repetitive knee movement task. The task, which required stabilisation of the lumbo-pelvic region, was performed at multiple movement speeds and at multiple time points during and after bed-rest.

Results:  After excluding effects that could be attributed to increases in subcutaneous fat changes and improvements in movement skill, we found that the RVE intervention ameliorated the generalised increases in activity ratios between movement speeds (p⩽0.012), reductions in lumbo-pelvic extensor and flexor co-contraction (p=0.058) and increases in root-mean-square electromyographic amplitude (p=0.001) of the lumbar erector spinae muscles. Effects of RVE on preventing increases in amplitude-modulation (p=0.23) of the lumbar erector spinae muscles were not significant. Few significant changes in activation-timing were seen.

Conclusion: The RVE intervention during bed-rest, with indirect loading of the spine during exercise, was capable of reducing some, but not all, motor control changes in the lumbo-pelvic musculature during and after bed-rest.

Copyright © 2011 Elsevier Ltd. All rights reserved.

PMID: 22018458

Study Introduction:

Bed-rest represents a unique model of extreme musculoskeletal disuse, particularly of the lower quadrant (Booth and Gollnick,1983). The methodology of prolonged bed-rest was originally developed to act as a simulation of the effects of spaceflight on the human body (Nicogossian and Dietlein, 1982).

An additional aim of space agencies in implementing bed-rest studies is to better understand the effect of ‘‘inactivity’’ on the human body and in so doing aiming to improve our management of illness on Earth. Specifically in the musculature, the muscle groups most affected by bed-rest are those involved in upright posture and locomotion, such as the triceps surae, vasti and lumbar spine extensors (Belavy´ et al., 2011, 2009b).

In recent works, we have attempted to gain a better understanding of the effects of bed-rest on motor control at the lumbo-pelvic region (Belavy´ et al., 2010, 2007a,b). Some of the findings have included development of generalized over activity in the superficial lumbo-pelvic muscles, more phasic activation of the lumbar erector spinae and shift to higher median activation frequencies in this same muscle.

However, aside from gaining a better understanding of the effects of bed-rest on the human body, another goal of bed-rest studies is the development of countermeasures against the changes seen in spaceflight simulation. This information will help not only in the development of (exercise) programs for preventing musculoskeletal deterioration in spaceflight, but may also better insight into treatment regimes on Earth for deconditioned patients.

In the Berlin Bed-Rest Study (Armbrecht et al., 2010; Rittweger et al., 2006), a high-load resistive exercise program with whole-body vibration (RVE) was implemented. This exercise program was targeted predominately at the bones (Armbrecht et al., 2010; Rittweger et al., 2010) and muscles (Belavy´ et al., 2009c; Blottner et al., 2006; Mulder et al., 2006) of the lower limbs.  Nonetheless, indirect loading of the lumbar spine occurred via shoulder straps. Magnetic resonance imaging investigations in these same subjects showed that the RVE subjects exhibited less atrophy of the short lumbar spine extensor muscles than in the control subjects (Belavy´ et al., 2008). Hence, we hypothesized that the RVE countermeasure would ameliorate the extent of motor control changes, as measured by electromyography, seen in the lumbo-pelvic muscles of the inactive control subjects.

J Endocrinol Invest. 2012 Jan;35(1):54-62. doi: 10.3275/7606. Epub 2011 Mar 21.

The effects of bed-rest and countermeasure exercise on the endocrine system in male adults: evidence for immobilization-induced reduction in sex hormone-binding globulin levels.

Belavý DL, Seibel MJ, Roth HJ, Armbrecht G, Rittweger J, Felsenberg D.

Source:  Charité University Medical School, Center for Muscle and Bone Research, Berlin, Germany. belavy@gmail.com

Abstract

BACKGROUND AND AIM:  There is limited data on the effects of inactivity (prolonged bed-rest) on parameters of endocrine and metabolic function; we therefore aimed to examine changes in these systems during and after prolonged (56- day) bed-rest in male adults.

SUBJECTS AND METHODS:  Twenty healthy male subjects underwent 8 weeks of strict bed-rest and 12 months of follow-up as part of the Berlin Bed Rest Study. Subjects were randomized to an inactive group or a group that performed resistive vibration exercise (RVE) during bed-rest. All outcome parameters were measured before, during and after bed-rest. These included body composition (by whole body dual X-ray absorptiometry), SHBG, testosterone (T), estradiol (E2), PRL, cortisol (C), TSH and free T3 (FT3).

RESULTS:  Serum SHBG levels decreased in inactive subjects but remained unchanged in the RVE group (p<0.001). Serum T concentrations increased during the first 3 weeks of bed-rest in both groups (p<0.0001), while E2 levels sharply rose with re-mobilization (p<0.0001). Serum PRL decreased in the control group but increased in the RVE group (p=0.021). C levels did not change over time (p≥0.10). TSH increased whilst FT3 decreased during bed-rest (p all ≤0.0013).

CONCLUSIONS:  Prolonged bed-rest has significant effects on parameters of endocrine and metabolic function, some of which are related to, or counteracted by physical activity.

PMID:  21422800