SUMMARY1. The purpose of the present study was to analyse the incidence and type of coordination between breathing rhythm and leg movements during running and to assess the effect of co-ordination on the running efficiency, as well as to compare the results with those found during cycling.2. The experiments were carried out on thirty-four untrained volunteers exercising at two work loads (60 and 80% of subject's physical work capacity 170) on a treadmill. In addition nineteen of the subjects exercised at the same two work loads on a bicycle ergometer. The subjects were running at both work loads in three different modes in randomized order: with normal arm movements, without arm movements and with breathing paced by an acoustic signal which was triggered by the leg movement.3. Respiratory variables, oxygen uptake and leg movements were continuously recorded and evaluated on-line. The degree of co-ordination was expressed as a percentage of inspirations and/or expirations starting in the same phase of the step or pedalling cycle.4. The average degree of co-ordination was higher during running (up to 40%) than during cycling (about 20%) during both work loads. The difference in the degree of co-ordination between running and cycling is probably not due to the lack of arm movements during cycling since the degree of co-ordination during running with and without arm movements was the same.5. The degree of co-ordination during running increased slightly but not significantly with increasing work load and could be increased significantly by paced breathing.6. The co-ordination between breathing and running rhythms occurred in three different patterns: (a) breathing was co-ordinated all the time with the same phase of step, (b) co-ordination switched suddenly from one phase of step to another and (c) co-ordination ensued alternatively once on the right and once on the left leg movement. During cycling the pattern described in (a) occurred almost exclusively.7. During running with a high degree of co-ordination, oxygen uptake for a given work load was slightly but significantly lower than during running with weak coordination.MS 1640 23 PHY 471 P. BERNASCONI AND J. KOHL

The results of this study suggest that ADAMs are differentially expressed in human breast cancer and are capable of modulating tumour cell growth.

The influence of the degree of coupling between the breathing and cycling rhythms (K) on oxygen uptake (Vo2) was examined in 30 volunteers. They cycled on an ergometer with a load equal to 50% of their work capacity 170 in two experimental runs with spontaneous breathing rhythm, and in a further two runs with acoustically triggered breathing. K was continuously ascertained. Vo2 and other respiratory parameters were measured by an automatic "breath-by-breath analysis" system. In 16 subjects, Vo2-differences between runs were correlated with the differences in K. In the majority of these subjects (12), Vo2 decreased significantly with increasing K. In 14 subjects, Vo2-and K-variations within individual runs were analyzed. Phases with higher K were regularly accompanied by a decrease in Vo2. It is concluded that coupling the breathing and cycling rhythms reduces Vo2 for a given moderate work load, although the magnitude of the Vo2-reduction varies considerably between individuals.

No abstract

The relationship between pedalling- and breathing rhythm was studied in 34 medical students (non-cyclists") and 10 racing cyclists on an electromagnetic bicycle-ergometer, the effective work load of which (50 W, 100 W, 150 W, 200 W) was independent of the pedalling rate. The criteria used were integer p/b ratios (pedalling rate being a multiple of breathing frequency) and phase coupling (the breathing phases starting preferentially at a certain angle of the pedalling cycle). Unconsciously occurring coordination of pedalling and breathing rhythm was found in the majority of the test persons; 70%-100% of the racing cyclists, 50%-63% of the regularly breathing and 25%-33% of the decreased with increasing work load. Phase coupling was even more frequent than integer p/b ratios and was not affected by increasing work load. The majority of racing cyclists (unlike the non-cyclists) coupled the inspiration-onset with the onset of either the left or the right leg movement. Expiratory phase coupling, however, was analogous in all groups; expiration began preferentially at mid-contraction of either leg. The results are discussed in terms of relative (nervous) coordination. It is concluded that the tendency to coordination between pedalling- and breathing rhythm increases with pedalling training and with regularity of breathing.