In the previous article [5] we wrote about the necessity of relaxing the patient’s muscles before the manual therapy session and about the expediency of using the ‘Gravitrin’ device for this purpose. But a number of questions connected with the specific peculiarities of using this device were not covered. In particular, the duration of a single correction on the ‘Gravitrin’ was not substantiated. The substantiation of the rational duration of a single stretching on ‘Gravitrin’ is an important scientific-practical task. The insufficiently long duration of the correcting procedure results in an incomplete effect of the treatment. Consequently more procedures will be needed for the complete recovery and restoration of the functional condition of the patient’s spine. The course of correction will become longer and the efficacy of the treatment according to the ‘price-quality’ criteria will lessen. Conversely, the unjustified prolongation of the therapy session with the help of the ‘Gravitrin’ also worsens the economic indicators of using this method: during any one shift fewer patients can get the treatment. One potential danger remains, connected with ‘over-dosing’ of the stretching. This is the possibility of reducing the therapeutic effect of the treatment and even developing complications. That is why it is necessary to clearly imagine the dynamic of the functional condition of the patient during the treatment session with the help of ‘Gravitrin’

Working method

The substantiation of the duration of a single stretching on the ‘Gravitrin’ was conducted in experiments with 16 patients with obvious clinical signs of osteochondrosis of the spine (nine women and seven men). The average age of the men was 41.6 years and that of the women 43.8 years. The patients were put on the apparatus in accordance with methods [2] and stretching with the help of ‘Gravitrin’ went on for 35-45 minutes. During the procedure they were asked every five minutes about their subjective feelings, one point being awarded for complete comfort - the ‘feeling of relaxing’ - two points for a feeling of satisfaction, three points for a ‘feeling of tension’ and four points for reporting some discomfort and expressing a desire to stop the procedure. At the same time a measurement was taken of the muscle tonus in the region of the middle chest part of the spine on the left side – midway between the corner of the shoulder blade and the spinous protuberance of the seventh chest vertebra. The measuring was made with a miotonometer of original construction, the principle of its work conforming to that described by G. A. Ivanichev [1]. The results of the research were arrived at using traditional methods of statistics [3], and a personal computer and the Microsoft Excel-98 package of programs.

Research results

A regular dynamic of the subjective evaluation of the duration of the stretching was noted. For the first 5 – 15 minutes the patients felt some tension (three points) and, in our opinion, that was connected with overcoming the resistance of the muscles of the back and small of the back during their axial stretching with the aid of the ‘Gravitrin’. Later some patients felt complete comfort (one point), but in the majority of cases during 5 – 10 minutes of the intermediate phase patients reported a ‘feeling of satisfaction’ (two points). By the 30 th minute of treatment the complete comfort again changed to a feeling of satisfaction, and for some of the patients after 30 minutes (12.5% of patients) and after 35 minutes (for half of the patients) there was a feeling of discomfort and a wish to stop the procedure (four points). After the 40 th minute all patients felt discomfort. The average dependence of the subjective feelings during treatment is shown in Figure 1.The changing of the patients’ muscle tonus during stretching with the help of the ‘Gravitrin’ also proceeded according to intermediate rule: at first the magnitude of muscle tonus sharply decreased and then, after a period of stability at that low level, again increased (see Figure 2). Because the initial values of the researching indicator differed greatly from patient to patient (from 1.0 to 4.1kg/cm2) for greater accuracy of the results we analysed relative figures and for 100% the level of muscular tonus was taken measured on the particular person immediately after being placed on the ‘Gravitrin’. A reliable inverse correlation was established between the subjective evaluation of the procedure and the muscle tonus (see Figure 3); r= - 0.521; p<0.01).points time, minutes.
 

 
100% is the level of the muscles’ tonus measured at once after laying the patient on the ‘Gravitrin’.  

Discussing the results

The reduction of back muscles tension during correction with the help of the ‘Gravitrin’ was caused, in our opinion, by three main factors. Firstly, the procedure is conducted with the patient lying on the supportive surfaces. So that load is removed from the anti-gravitational extensor muscles of the back. Secondly, the ‘Gravitrin’ supportive surfaces take the form of the adjacent parts of the patient’s body, minimizing pressure on the soft tissues. Evidently, these circumstances condition the quick reduction of the tonus of the muscles in the first five minutes of treatment (see Figure 1). Thirdly, a definite role is played by the axial stretching of the patient’s torso. The traction generated by ‘Gravitrin’ is aimed at stretching most of the back’s extensor muscles. The prolonged passive (in relation to muscle) effort causes (a) powerful proprioceptive afferentation at the expense of activation of the receptors of muscles, ligaments and tendons, normalizing nerve control of the muscles tonus, (b) the mechanical straightening of the shortened (by spasm) muscles formation. Of particular interest is the increase of muscular tonus following 30-35 minutes of stretching on the ‘Gravitrin’, which coincides with a lowering of patients’ subjective evaluation of the comfort of the treatment. The nature of this phenomenon calls for additional scrutiny. We consider that it can have a number of reasons. In the first place there is a gradual pressure on those soft tissues of the patient that are touching the ‘Gravitrin’s ‘ hard ribs. Although the supportive surfaces of the bed are assuming the form of the adjacent part of the patient’s body, lessening the total pressure, the patient lies during the procedure practically without movement and because of high mechanical pliancy of skin and muscles in due course there develops squeezing of blood vessels and nerves in the most critical zones. All this leads to reflex muscular tension (hardening of the tissue) and the appearance of feelings of discomfort. In the second place, as the axial stretching of the spinal column progresses, some physiological barrier appears (resilient barrier [4]), which also leads to a reflex protective increase of muscle tonus. The received results help to establish a scientifically grounded standard for the length of the ‘Gravitrin’ correcting procedure. It is obvious that the effectiveness of the spinal stretching session depends on overcoming the muscles’ resistance. As follows from the data previously given, the maximum reduction of the muscles tonus (i.e. their maximum relaxing) occurs in 5-15 minutes after the start of the procedure. This means that in every case the duration of the correction cannot be shorter than 15 minutes. If ‘Gravitrin’ is used for preparing the patient for manual therapy, the session can be limited to ten minutes. In the case of functional correction the stretching must be carried out throughout the period of maximum relaxing of the musculature – i.e. it must continue during 30 minutes.

Conclusions

1. The dynamic of subjective evaluation by patients of the procedure of stretching on the ‘Gravitrin’ is complicated: after a brief (5-15 minutes) feeling of ‘tension’ comes a feeling of comfort (in the following 15-25 minutes) which in the 30th to 40th minute of the procedure turns into a feeling of discomfort.
2. The back muscles tonus of patients undergoing correction on the ‘Gravitrin’ changes, depending on the duration of the procedure according to intermediate rule: at first sharply decreases (up to the fifth minute), stays at the low level for the next 20-25 minutes, and increases to the 35th – 40th minute.
3. There is a reliable inverse correlation between patients’ perception of the ‘Gravitrin’ correction procedure and the tonus of the back muscles: the lower the tonus the more comfortable the procedure.
4. The duration of the preparation of patients on the ‘Gravitrin’ for manual therapy treatment is 10 – 15 minutes.
5. The duration of the correcting session on ‘Gravitrin’ is 30 minutes.