Compression Sleeves Significantly CounteractsMuscular Fatigue During Strenuous Arm Exercise (P124) Thibaud Thedon1,2, Nicolas Belluye2, Stéphane Perrey1 Topics: Exercise physiology, muscular performance, textile, engineering processes.
Abstract: The principle of external compression (EC) regularly used in people with
peripheral venous insufficiency has been shown to exhibit an increased oxygenation in
healthy subjects at rest on gastrocnemius muscle (Bringard et al. 2006). During exercise, EC
allows decreasing electromyography activity (EMG) of hamstrings (sprint; Ringaud et al.
2003) and increasing arterial flow in forearm (task of handgrip; Bochmann et al. 2005).
However, no study has underlined the benefit of EC during strenuous exercise, known to
alter neuromuscular (force, EMG) and haemodynamic (blood volume, oxygenation) func-
tion. After a standardized warm-up, 4 healthy subjects were required to maintain with or
without forearm EC (randomised order) a handgrip force equal to 60% of their maximal
voluntary force (MVF) until exhaustion. Before and after this task, they realized three MVF.
The blood volume (Hbtot) and oxygenation (HbO2) of forearm flexor digitorum superfi-
cialis muscle was recorded by near infrared spectroscopy. The EMG RMS activity of flexorcarpi ulnaris muscle was recorded with A/D system (MP30, Biopac systems, Inc, USA). WithEC, the time to exhaustion was improved of 8% (P > 0.05). After fatigue, our results showeda less important decrease of MVF (11%, P < 0.05) and a higher neuromuscular efficiency(force/EMG) of 22% (P < 0.05) with EC. Hbtot was higher of 61% (P = 0.06) and HbO2 value increased of 90% (P > 0.05) during exercise with EC. As a conclusion, EC over an active
muscular region seems to counteract efficiently the deleterious effects of muscular fatigue.
Keywords: Muscular fatigue, blood circulation, exercise, compression.
1- IntroductionMuscle fatigue can be caused by repeated or prolonged isometric or concentric musclecontractions. It is commonly defined as a decrease of the physiological efficiency duringa prolonged task that can lead to the stop of the exercise after a certain time. This “failuretime” or “endurance time” strongly depends on the force exerted and more generally on 1. Motor Efficiency and Deficiency Laboratory EA 2991, UFR STAPS, 700 avenue du Pic Saint Loup, 34090 Montpellier,FRANCE - E-mail: thibaud.thedon, [email protected] Décathlon, 4 Bd de Mons, 59650 Villeneuve d’Ascq - E-mail: nicolas.belluye, thibaud.thedon}@decathlon.com 642 The Engineering of Sport 7 - Vol. 1
the physiological and mechanical work performed by the subject. During sustainedsubmaximal contractions, three main markers of fatigue can be observed (Bigland-Ritchie et al. 1986): the increase of the electromyography (EMG) amplitude, the decreaseof the frequency content of the EMG signal, and the gradually increasing voluntaryeffort needed to maintain the force output. During a sustained voluntary submaximalcontraction there is a progressive increase in motor unit activity that can include achange in the number of active motor units and a modulation of discharge rate(Bigland-Ritchie at al. 1986, Lippold et al. 1960). The mechanism by which the slowingof motoneuron firing occurs has been the subject of many investigations but remainsunclear. During muscle contraction, it is well known that if the supply of O2 is not adap- ting quickly enough to the needs, because of low perfusion pressure, adaptation ofoxydative metabolism will decrease (Perrey et al. 2001). Changes in muscle oxygen deli-very and muscle perfusion are known to affect force or power output of the muscle(Wright et al. 1999). When blood flow is diminished, both muscle endurance and oxyge-nation decrease, leading to muscle fatigue (Tachi et al. 2004). Motor unit firing andrecruitment patterns have been shown to be altered during ischemia (Moritani et al.
1992), suggesting that the lack of oxygen availability increases motor unit discharge rateof high- threshold units (i.e. which are more likely to lead to a fatigue state).
The technique of near infrared spectroscopy (NIRS) has been used for several years to evaluate oxygenation during physical work. NIRS has been used initially as a researchtool to assess dynamic changes in the status of tissue oxyhaemoglobin (HbO2), deoxy- haemoglobin (HHb), total blood haemoglobin (Hbtot) in brain and muscle. It is a non- invasive method for monitoring oxygen availability and use by the tissues. Humanforearm muscle blood flow by NIRS has been compared with venous occlusion plethys-mography showing a good correlation (Edwards et al. 1993, DeBlasi et al. 1994). In afatigue task induced by sustained isometric contraction, Hicks et al. (1999) displayed areduction of venous blood O2 saturation of the forearm at 30% of maximal voluntary force (MVF). With the elbow flexor muscles (brachioradialis muscle) the maximaldeoxygenation was obtained at 50% MVF (Kahn et al. 1998). On the back muscles, signi-ficant variations of blood volume and tissue oxygenation were also demonstrated(Yoshitake et al. 2001). In their study, McGill et al. (2000) suggested that the oxygenationdecrease arises from an alteration of blood flow in capillary bed during isometriccontraction. Finally, Tachi et al. (2004) demonstrated that isometric exercise performedin a leg up condition (i.e. with reduced perfusion pressure) induced a decrease in muscleoxygenation.
A recent study on external compression (EC) products usually used in people with venous insufficiency showed an increase in tissue oxygenation of calf muscle, measuredby NIRS, in healthy subjects at rest (Bringard et al. 2006). In this study, an appropriatebut moderate pressure of 20 mmHg applied over the calf resulted in an increased muscleoxygenation and decreased Hbtot and HHb in comparison with regular shorts andelastic tights. Their findings suggest that EC may improve significantly blood supply tomuscles and could enhance muscle function when fatigue occurs. If most studies showeda positive effect of EC on lower extremity, few have worked on upper limbs. Recently,Bochmann et al. (2005) have tested the hypothesis that EC increased forearm blood flow.
The Engineering of Sport 7 - Vol. 1
According to these authors, external compression pressure increases tissue pressure andconsequently decreases transmural vascular pressure. This decreased transmural pres-sure may trigger a myogenic response resulting in vessel relaxation. This may in turn leadto a flow rise in small arteries and arterioles. With different applications of pressuresfrom 20 to 30 mmHg, Bochmann et al. (2005) found a significant increase of arterialinflow. In addition, when this range of pressure was used during a task of handgrip (5-10% MVF, 1 s contraction / 2 s relaxation duty cycle for nearly 70 min), the arterial flowincreased significantly. However their measurement was not continuous.
Based on the aforementioned studies, this study aimed to evaluate continuously haemodynamic changes and muscle oxygenation with NIRS during a fatiguing task ofhandgrip. EMG and forearm flexor muscle force were measured to assess fatigue. Wehypothesised that the use of EC may counteract muscle fatigue by an enhanced O2 deli- 2.1 SubjectsThe effects of compressive sleeves on haemodynamics and muscle fatigue during andafter a fatiguing forearm exercise was tested during a pilot study in 4 healthy young andnormotensive males (age of 28 ± 3 years). Subjects were requested to refrain fromphysical exercise and any treatment for muscle soreness or damage for 48 hours prior toand during the study. The protocol complied with the Helsinki declaration for humanexperimentation and was approved by the local human ethics committee. Possible risksand benefits were explained and written informed consent was obtained from eachsubject before the experimentation.
2.2 Experimental proceduresThe subjects seated on a comfortable adjustable chair in front of a table, such that theirforearms were laid in a resting pronation position on the table at roughly heart level. Forall conditions, the subjects rested in a quiet room with constant temperature (~22 °C)to avoid changes in blood volume. The right side of the upper body was used for allsubjects. The elbow angle was flexed 90°. Subjects grasped a handle equipped with a forcetransducer (Dec 200, Captels, France). The two conditions (with and without EC) wererandomly performed in 2 separate sessions. The compression sleeves were made by acommercial manufacturer specialised in that field to deliver an appropriate compressionprofile to the largest cross-section area of the forearm (Bochmann et al. 2005). Externalpressure applied by sleeves on the skin was controlled by a validated pressure transducer(Kikuhime, TT Medi Trade, Soleddet 15, Sorro, DK). This small and flexible pressure-measuring device has an air-filled pressure bladder of 30 x 38 mm dimension and 3 mmthick when calibrated to zero.
After a short standardized warm-up (i.e., repeated contractions of moderate-inten- sity of the wrist muscles), subjects realized three MVFs separated by 60 s of passive rest.
644 The Engineering of Sport 7 - Vol. 1
The mean of the three MVFs values was used for analysis. The fatigue protocol consistedin a sustained isometric contraction of wrist flexors until exhaustion (i.e., task of hand-grip). The workload was fixed at 60% of the MVF measured at the beginning of theexperiment. A visual feedback was projected on a computer screen to allow subjects tocontrol their force level. Subjects had to continue the fatigue task until exhaustion, whenthey were unable to maintain the workload for at least 5 s. MVFs were also performedat the end of the experiment, in order to evaluate the effect of fatigue on force genera-tion capabilities.
2.2.1 EMG and force measurements
The force transducer was connected to an acquisition A/D board (MP-30 Bipoac Inc., USA). Force signal was recorded simultaneously with EMG activity. EMG of theflexor carpi ulnaris muscle was picked-up using 9-mm diameter bipolar Ag/AgCl elec-trodes (Contrôle Graphique Medical, Brie-Comte-Robert, France) with an inter-elec-trode distance of 25 mm. The reference electrode was placed on the wrist. Lowimpedance between the two electrodes (<5 k ) was obtained by abrading slightly theskin with emery paper and then by cleaning it with modified alcohol. All signals weresampled at 2,000 Hz and amplified and filtered (band pass 30– 500 Hz, gain = 1,000).
The MVF was quantified as the average value over a 1 s interval centered around the peak force. Root mean squared (RMS) and mean power frequency (MPF estimated by afast Fourier transform with Hanning window processing) of EMG were determined overthe same 1 s interval.
2.2.2 Muscle oxygenation measurements
Muscle oxygenation was assessed using the NIRS technique. The NIRS signal provides continuous, non-invasive monitoring of the relative concentration changes in HbO2 and HHb. Hbtot are the sum of HHb and HbO2 concentrations and give an index of the blood volume of the interrogated tissue region. In the present study, changes in Hbtot, HHb and HbO2 of the right forearm flexor muscles were continuously monitored at 2 Hz using a near-infrared spatially resolved spectroscopy oximeter (NIRO-300, HamamatsuPhotonics, Japan). Data were simultaneously transmitted to a personal computer using aRS-232C wire. NIRO-300 optodes were housed in an optically dense plastic holder, ensu-ring that their position relative to each other was fixed and invariant. The probe (i.e. theoptodes support) was secured on the cleaned skin surface with tape. The probe was placedover the muscle belly. The position of the probe on the muscle was marked carefully. Thedetector in the NIRS probe was separated from the light source by 40 mm. The lightemitted by the near infrared probe is assumed to depth tissues at 50% of the interoptodespacing (space between emitting and receiving probes). Skinfold thickness was measuredbetween the NIRS optodes using a skinfold caliper (Holtain Ltd., Crymmych, UK), andwas divided by 2 to determine the adipose tissue thickness (i.e. fat + skin layer) coveringthe muscle. The obtained values of adipose tissue thickness were 2.8 ± 0.9 mm, allowingthe NIRS photons to penetrate through the muscle. The absorption of light at differentwavelengths (775, 810, 850 and 910 nm) was analysed according to the modified Beer- The Engineering of Sport 7 - Vol. 1
Lambert’s law. Because the differential path length factor (DPF) reported in the literatureis estimated from a particular group of subjects, and hence it just represents a mean valuefor that group, no DPF was utilized in the present study. Changes in HbO2, HHb and Hbtot concentration were reported as a change from baseline values in micromolar units per centimetre (µM.cm). The HHb signal can be regarded as being essentially blood-volume insensitive during exercise, thus it was assumed to be a reliable estimator ofchanges in intramuscular oxygenation status and O2 extraction in the field of interroga- tion. Moreover, the NIRO-300 provides directly tissue haemoglobin oxygen saturation[tissue oxygenation index, TOI=HbO2/(HbO2+HHb) ҂ 100, expressed in percentage] calculated independently by using the spatially resolved spectroscopy method, whichexploits the source detector multidistance approach.
Since subjects realized different times of exercise, NIRS-derived variables were averaged each epoch of 10% of total time to exhaustion. Then, individual data each 10%were averaged together to obtain a mean group response.
2.2.3 Statistical analysis
Differences between EC and fatigue conditions (with and without) on NIRS-derived
variables, EMG and force values were assessed using a two-way (timeÍcondition)
repeated measures analysis of variance (ANOVA). The difference in time to exhaustion
with and without EC was tested using a paired t-test. Any differences were further
analysed with a Newman-Keuls post-hoc test. A two-way ANOVA was systematically
performed if data distribution fails the normality or equal variance tests. All values are
presented as mean ± SE. Statistical significance was accepted at P < 0.05.
3.1 Endurance timeNo significant difference was found among EC conditions although the time to exhaus-tion tended to increase with EC by 8%.
3.2 Neuromuscular fatigueAfter fatigue, a decrease of MVF of 40% was noted. The decrease of force was lesspronounced with EC than without (-12%, P < 0.05). For the flexor muscles, EMG MPFtended to decrease less with EC than without (-14% vs. -24%, respectively, P > 0.05).
Meanwhile EMG RMS normalised by RMS measured during MVF before exerciseincreased less with EC (+68% vs. +90%, respectively, P > 0.05). Finally, neuromuscularefficiency (Force/EMG RMS) was higher by 22% (P < 0.05) with EC.
3.3 NIRS variablesDuring exercise, HbO2, HHb, Hbtot, TOI were greater with EC than without (difference of +110%, +1.5%, +61%, +0.7%, respectively). Statistical analysis revealed no significantdifference (P > 0.05) for HbO2, HHb and TOI while P = 0.06 for Hbtot.
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4- DiscussionIn numerous occupations today the challenge on whole body human muscle power isvery small. Instead, small muscles in the upper extremities are repetitively and forprolonged periods of time performing low static forces relative to their maximumstrength. Consequently, the aim of this study was to evaluate haemodynamic changes(especially, Hbtot and TOI) during sustained handgrip exercise until exhaustion with and without an ergonomic interplay (i.e. EC) over the forearm flexor muscles. The mainresult of this study was that the use of EC sleeves during the sustained forearm exercisesignificantly diminished muscle fatigue without improving significantly enduranceperformance (+8 %).
Subjects were able to hold the initial 50% MVF for 98.1 s without EC and for 106.1 s with EC. These endurance times are well in the range of those previously published inthe literature in the absence of EC (Blackwell et al. 1999). It is worth noting that even ifthe endurance time was higher with than without EC in some subjects, this value wasgreater than or equal to that observed with EC in the other subjects, and there was there-fore no statistically significant difference between the overall endurance times observedwith and without EC. This finding is in agreement with the study of Maton et al. (2006)but is partly in contradiction with the decrease in the endurance time reported by Styf(1999) in subjects wearing contention braces. The discrepancy between these data andours may be attributable to differences in the pressure exerted by the garments testedand the limbs studied. Here, we used deliberately the human forearm because it is notinfluenced to hydrostatic pressure differences as much as lower limbs.
During sustained moderate force contractions, the decreased oxygen availability is associated with decrease in muscle activation and force production, i.e. fatigue develop-ment. Measurement of MVF is one direct method to assess muscle fatigue. The lowerdecline in MVF with EC (-12%) for equivalent endurance time suggests that EC coun-teracts muscle fatigue during strenuous forearm exercise. In the present study, musclefatigue was based on EMG recordings during the MVF and spectral analysis of theserecordings. During a long-lasting isometric force maintenance task, a decrease in EMGMPF accompanied by an increase in EMG RMS is known to reflect muscle fatigue(Bigland-Ritchie et al. 1986). This was the case in all trials tested. But again, EC tends tobetter overcome fatigue development with a lower decrease in MPF (10%) and a lowerincrease in RMS (22%). The decrease in MPF suggested that a decrease in muscle fibreconduction velocity had been induced by local metabolic changes (anaerobic compo-nent), i.e. those resulting from peripheral muscle fatigue. However, the possibility thatthese changes may have been of central origin (firing of the groups III and IV afferentssensitive to metabolic products and O2) cannot be ruled out, since MPF depends partly on motor unit recruitment. In the present study, we hypothesized that an increase inexternal pressure by sleeves and a subsequent increase in oxygenation and blood volume,measured within the muscle tissue by NIRS, resulted in lower muscle fatigue andpossibly underlined changes seen in the EMG responses during the sustained maximalforce contractions. Bochmann et al. (2005) showed an increase of arterial inflow as soonas EC is applied on forearm. In our study we have measured tissue oxygenation by NIRS The Engineering of Sport 7 - Vol. 1
method. At the beginning of exercise HbO2 and Hbtot were greatly enhanced with EC.
This can explain why subjects with EC increased their endurance times (+8%) becausemore oxygen was available. Moritani et al. (1992) suggested that if O2 availability decreases, time of endurance decreases too, because fast twitch fibres are recruited prefe-rentially. Supply in O2 is very important at the beginning of exercise to meet the ener- getic demand. Finally, during the MVC, we calculated the neuromuscular efficiency asthe ratio of the force developed divided by RMS activity of the flexor carpi ulnarismuscle. This ratio was significantly higher with EC and confirms the real benefits ofcompressive sleeves to delay muscle fatigue during sustained forearm exercise.
In conclusion, this pilot study tends to show that EC might have a positive influence on muscle function of upper-extremity. The underlying mechanisms explaining thisfinding are unclear and further studies need to be performed by increasing the numberof subjects.
5- References[BF1] Bigland-Ritchie B., Furbush F. and Wood J.J. Fatigue of intermittent submaximal volunta-ry contractions: central and peripheral factors. In Journal of Applied Physiology, 61: 421-429,1986[BD1] Bringard A., Denis R., Belluye N. and Perrey S. Effects of compression tights on calf muscleoxygenation and venous pooling during quiet resting in supine and standing positions. In Journalof Sports and Medicine in Physical Fitness, 46: 548-554, 2006[BS1] Bochmann R.P., Seibel W., Haase E., Hietschold V., Rödel H. and Deussen A. External com-pression increases forearm perfusion. In Journal of Applied Physiology, 99: 2337-2344, 2005[DF1] DeBlasi R.A., Ferrari M., Natali A., Conti G., Mega A. and Gasparetto A. Noninvasive mea-surement of forearm blood flow and oxygen consumption by near-infrared spectroscopy. InJournal of Applied Physiology, 76: 1388-1393, 1994[ER1] Edwards A.D., Richardson C. and van der Zee P. Measurement of hemoglobin flow andblood flow by nearinfrared spectroscopy. In Journal of Applied Physiology, 75: 1884-1889, 1993[HM1] Hicks A., McGill S. and Hughson R.L. Tissue oxygenation by near-infrared spectroscopyand muscle blood flow during isometric contractions of the forearm. In Canadian Journal ofApplied Physiology, 24: 216-230, 1999[KJ1] Kahn J.F., Jouanin J.C., Bussière J.L., Tinet E., Avrillier S., Ollivier J.P. and Monod H. Theisometric force that induces maximal surface muscle deoxygenation. In European Journal ofApplied Physiology, 78: 183-187, 1998[LR1] Lippold O.C., Redfearn J.W. and Vuco J. The electromyogram of fatigue. In Ergonomics, 3:121-131, 1960[MH1] McGill S.M., Hughson R.L. and Parks K. Lumbar erector spinae oxygenation during pro-longed contractions: implications for prolonged work. In Ergonomics, 43: 486-493, 2000[MS1] Moritani T., Sherman W.M., Shibata M., Matsumoto T. and Shinohara M. Oxygen availa-bility and motor unit activity in humans. In European Journal of Applied Physiology, 64: 552-556,1992[MB1] Maton B., Thiney G., Ouchène A., Flaud P., Barthelemy P. Intramuscular pressure and sur-face EMG in voluntary ankle dorsal flexion: Influence of elastic compressive stockings. In Journalof Electromyography and Kinesiology, 16: 291-302, 2006 648 The Engineering of Sport 7 - Vol. 1
[PT1] Perrey S., Tschakovsky M.E. and Hughson R.L. Muscle chemoreflex elevates muscle bloodflow and O2 uptake at exercise onset in nonischemic human forearm. In Journal of AppliedPhysiology, 91: 2010-2016, 2001[S1] Styf J. The effects of functional knee bracing on muscle function and performance. In SportsMedicine, 28: 77-81, 1999 [TK1] Tachi M., Kouzaki M., Kanehisa H. and Fukunaga, T. The influence of circulatory differen-ce on muscle oxygenation and fatigue during intermittent static dorsiflexion. In European Journalof Applied Physiology, 91: 682-688, 2004[YU1] Yoshitake Y., Ue H., Miyazaki M. and Moritani T. (2001). Assessment of lower-back musclefatigue using electromyography, mechanomyography, and near-infrared spectroscopy. In Journalof Applied Physiology, 84: 174-179, 2001[WM1] Wright J.R., McCloskey D.I. and Fitzpatrick R.C. Effects of muscle perfusion pressure onfatigue and systemic arterial pressure in humans subjects. In Journal of Applied Physiology, 86:845-851, 1999

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