A common question over the last few weeks.
Does it matter, where I mount the MOXY unit.
A; Yes and no.
If you look at trends it does not matter. We did test on the quadriceps on vastus lateralis , medialis and rectus with three moxy's at the same time.
Result: Different " absolute " SmO2 numbers, . Same trends in all. ( As usual exceptions.
depending on your leg extension angel the vastus medialis is different , when you restrict the extension to the last 5 - 10 degrees. In the neutral zero international ROM language meaning if you go form Ext/ Flex ( 0/0/10 ). Than you have very little information in the other two but only if you have a 90 degree hipflexion.
. For users on a bike or running or rowing very little difference . So if you test on a specific area than keep the same area when you work it as close as possible and you will have a very accurate repetition of the trends as well as of SmO2.
In this cases you can see changes and can make some conclusions.
Can you make a conclusion , what may happen in the other leg or in the upper body.
Same again, yes and no.
The best is to actually compare the two legs in sports , where a symmetrical work is crucial for performance. ( Biking , running, rowing and so on. Here you can use left and right leg MOXY as you easy can afford this now, in fact you can buy 12 moxy for the same cost as a traditional NIRS and still be cheaper.
Same wave length so same info in trend for sure.
. Examples what we do.
Left and right leg moxy in sports like Speed skating , rowing cycling for example.
Upper and lower body MOXY in sports like cross country skiing , rowing, wrestling for example.
MOXY in upper , lower body and on a respiratory muscle to see, when an how core stability may fall apart due to priority to breathing than core stability.
Here accepted studies who support our crazy ideas.
First symmetric question, second Postural challenge when respiration is the Limiter.
Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.
Hesford CM, Laing SJ, Cardinale M, Cooper CE.
Department of Biological Sciences, University of Essex, United Kingdom. firstname.lastname@example.org
It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters.
Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS.
Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P < 0.05) in the final lap. Total muscle blood volume decreased equally in both legs at the start of the simulation. However, during subsequent laps, there was a strong asymmetry during cornering; when skaters traveled solely on the right leg, there was a decrease in its muscle blood volume, whereas an increase was seen in the left leg.
NIRS was shown to be a viable tool for wireless monitoring of muscle oxygenation. The asymmetry in muscle desaturation observed on the two legs in short-track speed skating has implications for training and performance
Postural activity of the diaphragm is reduced in humans when respiratory demand increases
Prince of Wales Medical Research Institute and University of New South Wales, Sydney, Australia
Received April 27, 2001; Accepted August 29, 2001.
- Respiratory activity of the diaphragm and other respiratory muscles is normally co-ordinated with their other functions, such as for postural control of the trunk when the limbs move. The integration may occur by summation of two inputs at the respiratory motoneurons. The present study investigated whether postural activity of the diaphragm changed when respiratory drive increased with hypercapnoea.
- Electromyographic (EMG) recordings of the diaphragm and other trunk muscles were made with intramuscular electrodes in 13 healthy volunteers. Under control conditions and while breathing through increased dead-space, subjects made rapid repetitive arm movements to disturb the stability of the spine for four periods each lasting 10 s, separated by 50 s.
- End-tidal CO2 and ventilation increased for the first 60–120 s of the trial then reached a plateau. During rapid arm movement at the start of dead-space breathing, diaphragm EMG became tonic with superimposed modulation at the frequencies of respiration and arm movement. However, when the arm was moved after 60 s of hypercapnoea, the tonic diaphragm EMG during expiration and the phasic activity with arm movement were reduced or absent. Similar changes occurred for the expiratory muscle transversus abdominis, but not for the erector spinae. The mean amplitude of intra-abdominal pressure and the phasic changes with arm movement were reduced after 60 s of hypercapnoea.
- The present data suggest that increased central respiratory drive may attenuate the postural commands reaching motoneurons. This attenuation can affect the key inspiratory and expiratory muscles and is likely to be co-ordinated at a pre-motoneuronal site.
The central nervous system co-ordinates the motor activities of all trunk muscles, including the diaphragm, during both postural and respiratory tasks.
Exercise-induced respiratory muscle fatigue: implications for performance
1. Lee M. Romer1 and
2. Michael I. Polkey2
+ Author Affiliations
1. 1Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge; and 2Respiratory Muscle Laboratory, Royal Brompton Hospital, and National Heart and Lung Institute, London, United Kingdom
1. Address for reprint requests and other correspondence: L. M. Romer, Centre for Sports Medicine and Human Performance, Brunel Univ., Uxbridge UB8 3PH, United Kingdom (e-mail: email@example.com)
It is commonly held that the respiratory system has ample capacity relative to the demand for maximal O2 and CO2 transport in healthy humans exercising near sea level. However, this situation may not apply during heavy-intensity, sustained exercise where exercise may encroach on the capacity of the respiratory system. Nerve stimulation techniques have provided objective evidence that the diaphragm and abdominal muscles are susceptible to fatigue with heavy, sustained exercise. The fatigue appears to be due to elevated levels of respiratory muscle work combined with an increased competition for blood flow with limb locomotor muscles. When respiratory muscles are prefatigued using voluntary respiratory maneuvers, time to exhaustion during subsequent exercise is decreased. Partially unloading the respiratory muscles during heavy exercise using low-density gas mixtures or mechanical ventilation can prevent exercise-induced diaphragm fatigue and increase exercise time to exhaustion. Collectively, these findings suggest that respiratory muscle fatigue may be involved in limiting exercise tolerance or that other factors, including alterations in the sensation of dyspnea or mechanical load, may be important. The major consequence of respiratory muscle fatigue is an increased sympathetic vasoconstrictor outflow to working skeletal muscle through a respiratory muscle metaboreflex, thereby reducing limb blood flow and increasing the severity of exercise-induced locomotor muscle fatigue. An increase in limb locomotor muscle fatigue may play a pivotal role in determining exercise tolerance through a direct effect on muscle force output and a feedback effect on effort perception, causing reduced motor output to the working limb muscles.
the purpose of this minireview is to address the question of whether the respiratory demands of exercise contribute significantly toward exercise limitation, either directly through limitations of the respiratory muscle pump or indirectly through effects on limb blood flow and locomotor muscle fatigue. We describe the mechanical and metabolic costs of meeting the ventilatory requirements of exercise. We then ask whether the respiratory muscles fatigue with exercise, what factors contribute to any such fatigue, and what the implications of these factors are for exercise tolerance. Finally, we deal with the potential mechanisms by which respiratory muscle fatigue could compromise exercise tolerance and whether it is possible to overcome this potential respiratory limitation. Our review focuses on the healthy young adult exercising near sea level. However, we also consider special circumstances that determine the balance between metabolic demand and respiratory system capacity in the highly trained endurance athlete and the clinical implications for respiratory limitations to exercise in patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF).