Category: muscle physiology

New article published #3: whole body vibration effects on obese subjects

This article was published on Obesity Facts. It is the result of a collaboration i have with the Italian Auxological Institute. An organisation working every day to help obese patients and trying to develop innovative approaches to weight management. In this experiment we showed how whole body vibration with and without additional loading can induce acute increases in Growth Hormone which is very difficult to obtain with other forms of exercise in this population. In the obese, some endocrinological disturbances during acute endurance and resistance exercise have been identified inmany studies: a blunted growth hormone response, atrial natriuretic peptide and epinephrine release, and greater cortisol and insulin release. These hormonal disturbances might contribute to a suppressed lipolytic response, and/or suppressed skeletal muscle protein synthesis, as a result of acute endurance or resistance exercise, respectively. Our finding suggests that this form of exercise has the potential to be effective at least in the initial stages of an exercise programme in this population.

Obes Facts. 2012 Aug 24;5(4):567-574. [Epub ahead of print]

Growth Hormone-Releasing Effects of Whole Body Vibration Alone or Combined with Squatting plus External Load in Severely Obese Female Subjects.

Giunta M, Cardinale M, Agosti F, Patrizi A, Compri E, Rigamonti AE, Sartorio A.


Istituto Auxologico Italiano, Laboratorio Sperimentale di Ricerche Auxo-endocrinologiche, IRCCS, Milan, Italy.


Background: Whole body vibration (WBV) has been reported to exert growth hormone(GH)-releasing effects in healthy subjects. Despite the potential of WBV to positively affect body composition changes via lipolytic effects, few studies have been performed in obese subjects to date. Methods: This study evaluated the acute effects of WBV alone or in combination with squatting plus external load (WBV+S) on serum GH levels and blood lactate concentrations in 7 severely obese women (age 22 ± 5 years; BMI 39.9 ± 2.9 kg/m(2)). Results: WBV and WBV+S determined a significant GH increase (mean GH peaks 5.1 ± 1.9 ng/ml, p < 0.001 vs. basal, and 6.5 ± 3.7 ng/ml, p < 0.001 vs. basal, respectively), GH peaks occurring immediately after both exercise sessions. No significant differences were observed between GH peaks and GH net incremental area under the curve (nAUC) after both conditions (p = 0.39 and p = 0.53, respectively), the whole pattern of GH responsiveness being comparable among all the subjects. Lactate concentrations increased after both conditions (mean lactate peaks 2.0 ± 0.5 mmol/l, p < 0.05 vs. basal, and 4.5 ± 2.0 mmol/l, p < 0.001 vs. basal, respectively). The lactate response was significantly higher after WBV+S than after WBV (p < 0.05). Baseline GH and GH peak values positively correlated to baseline lactate and lactate peak concentrations in both conditions (R(2) = 0.64, p < 0.001, and R(2) = 0.52, p < 0.05, respectively). Conclusions: WBV alone stimulates GH release and lactate production in severely obese female subjects, with no additive effect when combined with squatting plus external load. Further additional studies are required to verify the chronic effects of WBV exercise on the GH/IGF-1 system, which could represent a potentially effective approach for weight management in obese subjects. Copyright © 2012 S. Karger GmbH, Freiburg.

New article published #2: Near Infrared Spectroscopy

This is published online first and will appear in print in 2013. Here we showed how good NIRS is when assessing elite athletes.

Adv Exp Med Biol. 2013;765:81-6.

NIRS Measurements with Elite Speed Skaters: Comparison Between the Ice Rink and the Laboratory.

Hesford C, Cardinale M, Laing S, Cooper CE.


Wearable, wireless near-infrared (NIR) spectrometers were used to compare changes in on-ice short-track skating race simulations over 1,500 m with a 3-min cycle ergometry test at constant power output (400 W). The subjects were six male elite short-track speed skaters. Both protocols elicited a rapid desaturation (∆TSI%) in the muscle during early stages (initial 20 s); however, asymmetry between right and left legs was seen in ΔTSI% for the skating protocol, but not for cycling. Individual differences between skaters were present in both protocols. Notably, one individual who showed a relatively small TSI% change (-10.7%, group mean = -26.1%) showed a similarly small change during the cycling protocol (-5.8%, group mean = -14.3%). We conclude that NIRS-detected leg asymmetry is due to the specific demands of short-track speed skating. However, heterogeneity between individuals is not specific to the mode of exercise. Whether this is a result of genuine differences in physiology or a reflection of differences in the optical properties of the leg remains to be determined.

[PubMed – in process]

New article published: Near Infrared Spectroscopy

This was recently published. Here we demonstrated how local measures of muscle oxygenation can provide clever information on metabolic demands and help the coaching process identify the appropriate training modalities to improve performance.

The abstract is below:

Med Sci Sports Exerc. 2012 Aug 14. [Epub ahead of print]

Effect of Race Distance on Muscle Oxygenation in Short-Track Speed Skating.

Hesford CM, Laing S, Cardinale M, Cooper CE.


1 Centre for Sport and Exercise Science, School of Biological Sciences, University of Essex, UK; 2 British Olympic Medical Institute, University College London, UK; 3 University of Aberdeen, School of Medical Sciences, Aberdeen, Scotland (UK), 4 School of Sport, Health and Exercise Sciences, Bangor University, UK.


Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown.


6 elite male skaters (age = 23 ± 1.8 years, height 1.8 ± 0.1m, mass = 80.1 ± 5.7kg, mid-thigh skin fold thickness = 7 ± 2mm), and 4 elite female skaters (age; 21 ± 4 years, height; 1.6 ± 0.1 m, mass; 65.2 ± 4.3 kg, mid-thigh skin fold thickness; 10 ± 1mm), were studied. Subjects completed time trials over 3 race distances. Blood lactate concentration and O2 uptake measurements were combined with NIRS measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis (VL).


Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSImax). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances local muscle desaturation reached maximal values much more quickly than global VO2peak.


The use of wearable NIRS devices enabled measurement of muscle oxygenation during competitive race simulation; thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.