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Good vibrations and strong bones?
Power Plate Studies
THE HUMAN PHYSIOLOGY of bone perfusion has been neglected.

The issue may be explained in part by technical difficulties in assessing bone blood flow in vivo. Currently available techniques may be rather expensive, and the access of interested scientists to these techniques may be limited. Another possible explanation for the neglect is the fact that the integration
between cardiovascular and bone research fails because each research area is narrowly focused on its own organ or tissue system. This state of affairs is unfortunate given the potentially important interactions between the cardiovascular system and bone. Indeed, bone and vascular disease frequently coexist in the same patients. Osteoporosis risk is increased in patients with atherosclerosis and vice versa. The correlation is probably explained in part by a common underlying mechanism rather than a spurious association. Bone perfusion may be such a common mechanism.

Perfusion appears to be matched to the metabolic demands of the bone. For example, increased bone turnover and inflammation are associated with an increased blood flow. Blood flow decreases as bone turnover normalizes or the inflammation has resolved. Failure of the vasculature to respond to metabolic needs of the bone might predispose to bone disease. Alterations in vascular function and in intraosseous angiogenesis may be contributory. Several studies suggest a correlation between bone perfusion and bone density. Studies used different methodologies and are, therefore, difficult to compare. In one study (8), magnetic resonance imaging was used to obtain an indirect measure of bone marrow perfusion at the level of the lumbar
spine. Bone marrow perfusion was correlated with bone mineral density in postmenopausal but not in premenopausal women. In another study (2), decreased bone marrow perfusion was associated with progression of collapse of fractured vertebra in patients with osteoporosis.

Perhaps “bone vascular disease” contributes to osteoporosis. One might further speculate that interventions that improve bone vascular function may have a beneficial effect on bone structure. The anatomic structure of blood small blood vessels within the bone is similar to the structure of blood vessels in other tissues. These vessels may be susceptible to the same genetic and environmental risk factors. If bone vascular disease and, thus, alterations in perfusion were a cause of excessive bone loss, atherosclerosis risk factors should also increase the risk for osteoporosis. Indeed, smoking, diabetes mellitus, elevated low-density lipoprotein cholesterol, reduced high-density lipoprotein cholesterol, and hyperhomocystinemia are associated with increased cardiovascular risk and reduced bone mineral density(4). Both the risk for cardiovascular disease and the risk for osteoporosis increase sharply after menopause. A study in rabbits suggests that experimental “postmenopause” through oophorectomy leads to changes in bone vascular function. In this study (1), oophorectomy increased the responsiveness of isolated vascular rings from small bone arteries to norepinephrine and to endothelin. However, whether vascular damage to the bone vasculature explains the association between osteoporosis and cardiovascular risk factors in humans is unknown.

Interestingly, treatment of some cardiovascular risk factors appears to have a beneficial effect on osteoporosis. For example, smoking cessation leads to an improvement in markers of bone turnover within a 6-wk period (5). Lipid-lowering therapy increases bone mineral density (3). Thiazide diuretics appear to lower the bone fracture rate (7). Moreover, beta blockers appear to do the same (6). Finally, estrogen replacement therapy improves bone density and endothelial function in humans.

If bone perfusion has an important effect on bone density, could an increase in bone perfusion also increase bone density? How can bone blood flow be increased? In this issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Stewart et al. (9) reviewed the literature on bone perfusion and bone mass. The few available publications seem to suggest that increased venous pressure and increased perfusion
tend to increase bone mass. They reasoned that an increase in leg and, perhaps, bone perfusion may contribute to the recently described increase in bone mass with whole body vibration (10).

To address this issue, they assessed changes in leg hemodynamics and fluid shifts using strain-gauge and impedance plethysmography
before and during whole body vibration. The vibration was elicited by placing the subjects on a vibrating platform. Whole body vibration increased blood flow to the lower body while subjects were in the supine position. Furthermore, the intervention reversed the decrease in leg blood flow in the upright position.

Finally, leg vibration shifted the microvascular filtration relation to higher pressures, both in the supine and in the upright position. The shift is probably explained by improved lymphatic drainage. Thus whole body vibration substantially altered leg hemodynamics. The study by Stewart et al. (9) necessarily has some limitations. The authors did not measure bone perfusion directly. It is difficult to know whether the change in leg blood flow is associated with a change in bone perfusion. I would suggest comparing “cheap” leg blood flow measurements with “costly” more direct measurements of bone blood flow in future studies. It would be tremendously helpful to have inexpensive methods that could be used to obtain hemodynamic measurements that
are relevant for bone hemodynamics. Furthermore, the authors did not provide data linking changes in hemodynamics and bone turnover. Perhaps more questions were raised than answered. Nevertheless, the study is of importance because it may generate interest in studying the interaction between bone and the cardiovascular system. Promising clinical and epidemiological data linking vascular disease and osteoporosis ought to be supported by solid physiological work. Equally important, the study suggests that even in the era of molecular medicine, a simple and “old-fashioned” physiological method is still useful to raise new scientific hypotheses. A final question for those who will not be interested in bones: Do good vibrations add to angiogenesis elsewhere?
 
Good vibrations and strong bones?
Power Plate Studies

Jens Jordan
Franz-Volhard Clinical Research Center, Charite´, Campus Buch and HELIOS Klinikum, Berlin, Germany
 
 
THE HUMAN PHYSIOLOGY of bone perfusion has been neglected. The issue may be explained in part by technical difficulties in assessing bone blood flow in vivo. Currently available techniques may be rather expensive, and the access of interested scientists to these techniques may be limited. Another possible explanation for the neglect is the fact that the integration between cardiovascular and bone research fails because each research area is narrowly focused on its own organ or tissue system. This state of affairs is unfortunate given the potentially important interactions between the cardiovascular system and bone. Indeed, bone and vascular disease frequently coexist in the same patients. Osteoporosis risk is increased in patients with atherosclerosis and vice versa. The correlation is probably explained in part by a common underlying mechanism rather than a spurious association. Bone perfusion may be such a common mechanism. Perfusion appears to be matched to the metabolic demands of the bone. For example, increased bone turnover and inflammation are associated with an increased blood flow. Blood flow decreases as bone turnover normalizes or the inflammation has resolved. Failure of the vasculature to respond to metabolic needs of the bone might predispose to bone disease. Alterations in vascular function and in intraosseous angiogenesis may be contributory. Several studies suggest a correlation between bone perfusion and bone density. Studies used different methodologies and are, therefore, difficult to compare. In one study (8), magnetic resonance imaging was used to obtain an indirect measure of bone marrow perfusion at the level of the lumbar spine. Bone marrow perfusion was correlated with bone mineral density in postmenopausal but not in premenopausal women. In another study (2), decreased bone marrow perfusion was associated with progression of collapse of fractured vertebra in patients with osteoporosis. Perhaps “bone vascular disease” contributes to osteoporosis. One might further speculate that interventions that improve bone vascular function may have a beneficial effect on bone structure. The anatomic structure of blood small blood vessels within the bone is similar to the structure of blood vessels in other tissues. These vessels may be susceptible to the same genetic and environmental risk factors. If bone vascular disease and, thus, alterations in perfusion were a cause of excessive bone loss, atherosclerosis risk factors should also increase the risk for osteoporosis. Indeed, smoking, diabetes mellitus, elevated low-density lipoprotein cholesterol, reduced high-density lipoprotein cholesterol, and hyperhomocystinemia are associated with increased cardiovascular risk and reduced bone mineral density(4). Both the risk for cardiovascular disease and the risk for osteoporosis increase sharply after menopause. A study in rabbits suggests that experimental “postmenopause” through oophorectomy leads to changes in         bone vascular function. In this study (1), oophorectomy increased the responsiveness of isolated vascular rings from small bone arteries to norepinephrine and to endothelin. However, whether vascular damage to the bone vasculature explains the association between osteoporosis and cardiovascular risk factors in humans is unknown. Interestingly, treatment of some cardiovascular risk factors appears to have a beneficial effect on osteoporosis. For example, smoking cessation leads to an improvement in markers of bone turnover within a 6-wk period (5). Lipid-lowering therapy increases bone mineral density (3). Thiazide diuretics appear to lower the bone fracture rate (7). Moreover, beta blockers appear to do the same (6). Finally, estrogen replacement therapy improves bone density and endothelial function in humans. If bone perfusion has an important effect on bone density, could an increase in bone perfusion also increase bone density? How can bone blood flow be increased? In this issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Stewart et al. (9) reviewed the literature on bone perfusion and bone mass. The few available publications seem to suggest that increased venous pressure and increased perfusion tend to increase bone mass. They reasoned that an increase in leg and, perhaps, bone perfusion may contribute to the recently described increase in bone mass with whole body vibration (10). To address this issue, they assessed changes in leg hemodynamics and fluid shifts using strain-gauge and impedance plethysmography before and during whole body vibration. The vibration was elicited by placing the subjects on a vibrating platform. Whole body vibration increased blood flow to the lower body while subjects were in the supine position. Furthermore, the intervention reversed the decrease in leg blood flow in the upright position. Finally, leg vibration shifted the microvascular filtration relation to higher pressures, both in the supine and in the upright position. The shift is probably explained by improved lymphatic drainage. Thus whole body vibration substantially altered leg hemodynamics. The study by Stewart et al. (9) necessarily has some limitations. The authors did not measure bone perfusion directly. It is difficult to know whether the change in leg blood flow is associated with a change in bone perfusion. I would suggest comparing “cheap” leg blood flow measurements with “costly” more direct measurements of bone blood flow in future studies. It would be tremendously helpful to have inexpensive methods that could be used to obtain hemodynamic measurements that are relevant for bone hemodynamics. Furthermore, the authors did not provide data linking changes in hemodynamics and bone turnover. Perhaps more questions were raised than answered. Nevertheless, the study is of importance because it may generate interest in studying the interaction between bone and the cardiovascular system. Promising clinical and epidemiological data linking vascular disease and osteoporosis ought to be supported by solid physiological work. Equally important, the study suggests that even in the era of molecular medicine, a simple and “old-fashioned” physiological method is still useful to raise new scientific hypotheses. A final question for those who will not be interested in bones: Do good vibrations add to angiogenesis elsewhere?
 
 
Whole body vibration training IMPROVES SPRINT PERFORMANCE
Power Plate Studies
Effects of whole body vibration training on sprint running kinematics and explosive strength performance.

This is a summary of a study published in the international scientific journal “Journal of Sports Science and Medicine” (2007) 6, 44 – 49.
By Giorgos Paradisis and Elias Zacharogiannis. Track and Field Unit, Department of Sport and Exercise science, University of Athens, Greece

Study Conclusions:Figure 1. Squat and Wide Squat positions exercised

Performance on the 10 m, 20 m, 40 m, 50 m and 60 m sprint improved significantly after 6 weeks of whole body vibration training, with an overall
improvement of 2.7%.

Step length and running speed improved by
5.1% and 3.6% respectively.

Countermovement jump height increased by 3.3%, and explosive strength endurance improved by 7.8% overall.

The whole body vibration training period of 6 weeks
- performed on the “classic” Power Plate® machine
- produced significant changes in sprint running kinematics and explosive strength performance.


Introduction

Sprint performance is determined by the ability to attain maximum running speed as fast as possible, achieving the highest running speed and by maintaining this speed for the required time or distance. By improving specific kinematics such as step length, step rate and running speed, as well as increasing explosive strength, sprint performance can be improved. These kinematics can be trained by improving optimal motor neuron excitability and fast twitch fiber recruitment.



Previous studies suggest that whole body vibration trainingFig. 2 A whole body vibration training period of 6 weeks produced significant positive changes in kinematical characteristics of sprint running. The results of the present study indicate that the gain of the step length was greater than the decrease of step rate (5.6% vs. - 3.9 %), so the net effect was an improvement of running speed, resulting in enhanced sprint performance.
causes length changes in the muscle which stimulates receptors,
most likely muscle spindles, eliciting the ‘tonic vibration reflex’.

This reflex plays a part in making movements more efficient.
Additionally, there are indications that the recruitment
thresholds of motor units of muscles during vibration are
lower, compared to voluntary contractions.

This means your
muscles will contract with a smaller stimulus, resulting in
faster reactions. As whole body vibration training is also
reported to improve fast twitch recruitment, it was hypothesized that whole body vibration training would result in a significant increase in sprint running kinematics and explosive strength/jumping performance in non-experienced
athletes.






Method

Twenty-four volunteers were randomized into two groups.
One group performed a 6-week training program on the Power Plate® machine; the control group did not participate in any training. The training group performed a warming up followed by a session on the Power Plate® machine for 16 to 36 minutes, three times per week. They performed 4 static exercises (squat, wide squat, one-legged squat for both legs, see fig. 1). For the first weeks, all of the exercises were performed at 30 Hz low and an acceleration of 2.28 g. During the course of their training, the program was intensified according to the overload principle:


Week Exercises Time
(sec)		 Repetitions Rest
between
exercises
(min)		 Sets Rest
between
sets
(min)
1-3 4 40 2 1 3 2
4-6 4 60 3 1 3 2





Results and conclusion

It can be argued that increasing step length could produce more velocity. However, if step length increases and muscle force remains the same, step rate should decrease.

Accordingly producing a slower step rate should lose the gain from a greater step length.

The results of the present study indicate that the gain of step length was greater than the decrease of step rate (5.6% vs. - 3.9 %), so the net effect was an improvement of running velocity (see fig. 2).


The whole body vibration training period of 6 weeks produced significant positive changes in kinematical characteristics of sprint running and explosive strength characteristics in non experienced sprinters, most likely due to the improved muscle contractions it provokes. The whole body vibration group showed improvement in all of the parameters that were tested: running time, running speed, step length, step rate and counter movement jump. The explosive strength endurance improved by 7.8 % (see fig. 2).


Sprint performance was enhanced, with a net effect of improvement of running velocity and decreased time interval over 60 meters. Jump height and explosive strength endurance also improved in the group that used the Power Plate® machine.



Overall, the conclusion of the researchers is that whole body vibration stimulates the sensory receptors and the afferent pathways, leading to a more efficient use of the stretch reflex. It allows for specific training of the fast-twitch fibers, contributing significantly to high-speed movements. In everyday life, improving these qualities will allow people to increase efficiency of movement and to prevent injuries.
 
Oxygen Uptake During Whole Body Vibration in Overweight Women
Power Plate Studies
OXYGEN UPTAKE DURING WHOLE BODY VIBRATION IN OVERWEIGHT WOMEN

DIRK VISSERS, KRIS IDES, CARL VERCRUYSSE,
STEVEN TRUIJEN and LUC VAN GAAL.university Antwerp logo

1University College of Antwerp , Dept. Of Health Sciences, Belgium
2 University of Antwerp and Antwerp University Hospital, Belgium

INTRODUCTION
  • Acceleration training or whole body vibration training has been described as an effective method for strength training.
  • To the best of our knowledge there are no studies on oxygen ventilation and energy expenditure during whole body vibration in overweight women.

AIM OF THE STUDY
To assess the effect of additional whole body vibration on the ventilation of oxygen which can be regarded as a measure for energy expenditure

METHODS
A controlled randomized trial.
  • Anthropometric measurements were taken in twenty adult overweight premenopausal women.
  • Ventilation of oxygen (VO2)and carbodioxide (VCO2) and heart rate were measured using a portable gas-analysis system (Cortex Metamax 3B) and a Polar heart rate monitor.
  • After each exercise a Borg scale score was assessed.
  • Exercises were performed on a vibration platform (Power-plate, Next Generation) with a frequency of 35 Hz and the intensity set on ‘high’ (amplitude of 4 mm).
  • Two dynamic exercises (standing on toes and squatting) and 1static exercise (standing) were performed during 3 minutes with and without vibration in a randomized order with 10 minutes rest between exercises. Mean values of the third minute of exercise were compared.
Overweight Women exercising on power plateStatistics of the resultsPower Plate Results Studying on Women

RESULTS
Ventilation of oxygen, carbon dioxide and heart rate were consistently significantly higher in the exercises with vibration
compared to the exercises without vibration.


CONCLUSIONS
The addition of whole body vibration to both static and dynamic exercises seems to increase the oxygen ventilation significantly in overweight women.

More research is needed to find out what is causing this increase and whether this increase is clinically relevant.

 
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