Abstract
ckground:Repeated sprint performance is determined by explosive production of power, as well as rapid recovery between successive sprints, and there is evidence that compression garments and sports taping can improve both of these factors. Methods:In each of two sub-studies, female athletes performed two sets of 30 30-m sprints (one sprint per minute), one set wearing compression garment with adhesive silicone stripes (CGSS) intended to mimic taping and the other with normal clothing, in randomized order. Sub-study 1 (n = 12) focused on cardio-respiratory, metabolic, hemodynamic and perceptual responses, while neuronal and biomechanical parameters were examined in sub-study 2 (n = 12). Results:In both sub-studies the CGSS improved repeated sprint performance during the final 10 sprints (best P<0.01,d= 0.61). None of the cardio-respiratory or metabolicvariables monitored were altered by wearing this garment (bestP= 0.06,d= 0.71). Also during the final 10 sprints, rating of perceived exertion by the upper leg muscles was reduced (P= 0.01,d= 1.1), step length increased (P= 0.01,d= 0.91) and activation of them. rectus femoriselevated (P= 0.01,d= 1.24), while the hip flexion angle was lowered throughout the protocol (best P<0.01,d= 2.28) and step frequency (bestP= 0.34,d= 0.2) remained unaltered. Conclusion:Although the physiological parameters monitored were unchanged, the CGSS appears to improve performance during 30 30-m repeated sprints by reducing perceived exertion and altering running technique. Keywords:Blood flow, Clothing, Oscillation, Oxygenation, Oxygen uptake, Textile, Tissue saturation index, Venous system, Video analysis Background Performance during repeated sprints separated by short periods of rest, a common aspect of team sports [1,2], is determined primarily by neuronal and metabolic factors (e.g., recruitment of muscle fibers and aerobic and anaerobic energy production [3,4]), as well as by the ability to recover between repeated bouts of explosive high-intensity activity [4,5]. Special running gear might improve this performance and, indeed, a recent meta- analysis revealed that lower-body garments that exert compression probably haveergogenic effects during sprinting [6]. Although
by neuronal and metabolic factors (e.g., recruitment of muscle fibers and aerobic and anaerobic energy production [3,4]), as well as by the ability to recover between repeated bouts of explosive high-intensity activity [4,5]. Special running gear might improve this performance and, indeed, a recent meta- analysis revealed that lower-body garments that exert compression probably haveergogenic effects during sprinting [6]. Although the mechanism (s) underlying the improvement of repeated sprint performance by compression is not yet clear, the enhanced muscle pump function and venous return [7,8] observed in clinical studies have been proposed as explanation for the elevated local hemodynamics during moderate [9], as well as intermittent high-intensity running [10]. Moreover, reduced blood lactate concentrations following high [11,12] or reduced oxygen uptake during moderate-intensity endurance exercise [13] were also associated with an ergogenic * Correspondence:dennis.born@web.de 1 Department of Sport Science, University of Wuppertal, Fuhlrottstraße 10, 42119 Wuppertal, Germany 3 Department of Sport Sciences, Integrative and Experimental Exercise Science, University of Würzburg, 97082 Würzburg, Germany Full list of author information is available at the end of the article © 2014 Born et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 http://biomedcentral.com/2052-1847/6/21
effect of compression clothing on local and central hemodynamics. In a manner similar to compression garments, applica- tion of elastic tape, originally used for therapeutic purposes [14], has been found to improve strength and power [15,16], although a recent meta-analysis was inconclusive with respect to muscle activity and pain [17]. Taping is thought to stimulate cutaneous mechano- and nocirecep- tors, thereby altering reflex activation and sensory feedback and increasing electromyographic activity [18,19], thereby enhancing proprioception [20] and muscle strength and power [15,16]. Since compression and taping each influence physio- logical, biomechanical and perceptual parameters, the primary goal of the present investigation was to examine whether the use of both together improves repeated sprint performance even further. In this context we tested a novel compression garment with adhesive silicone stripes (CGSS) designed to mimic both compression and sports taping. Our secondary goal was to identify the physiological, biomechanical and perceptual effects that might account for the ergogenic properties of this garment. Methods To reduce the necessity for bulky laboratory equipment during repeated sprinting, two sub-studies were per- formed: The first to investigate the influence of CGSS on repeated sprint performance and cardio-respiratory, metabolic, hemodynamic and perceptual variables; and the second to examine whether this special garment might exert an impact on biomechanical properties and running technique. A total of 24 female subjects were recruited from track-and-field or team sport clubs that regularly use re- peated sprinting as part of their training and randomly assigned to participate in sub-study 1 or 2. These women were instructed to report for all testing well-hydrated and to refrain from strenuous exercise for 48 h and from in- take of alcohol or caffeine for 24 h beforehand. After being informed of the benefits and risks involved, all provided their written consent to participate. This study was approved by the Ethical Committee of the University of Wuppertal, Germany, and executed in accordance with the Declaration of Helsinki. Design of sub-study 1 All athletes in sub-study 1 (n = 12; age: 25 ± 3 yrs; height: 167 ± 3 cm; body mass: 61 ± 5 kg; fat mass:
all provided their written consent to participate. This study was approved by the Ethical Committee of the University of Wuppertal, Germany, and executed in accordance with the Declaration of Helsinki. Design of sub-study 1 All athletes in sub-study 1 (n = 12; age: 25 ± 3 yrs; height: 167 ± 3 cm; body mass: 61 ± 5 kg; fat mass: 18 ± 5% (mean ± SD)) carried out two sessions of 30 30-m repeated sprints each, one wearing the CGSS and the other with non-compression tights without any adhesive silicone stripes, in randomized order. Each participant wore the same shoes and running shirt during both trials. All sprints were performed on an indoor track at a time when the subjects were not menstruating. After determination of body mass (Tanita BC 418 MA, Tanita Corp., Tokyo, Japan), the athletes warmed up for 20 min with moderate running, including five 5-m and 10-m sprints. During the repeated sprint protocol, each sprint was initiated by a verbal count-down once each minute. Starting 1 m behind the first gate, they were instructed to complete each 30-m sprint as fast as pos- sible, avoiding pacing, and thereafter to jog back to the starting line at a moderate pace. No feedback concerning performance was provided, in order to promote equal motivation to complete each sprint. Sprint times were recorded by timing gates (TDS Werthner Sport Consulting, Linz,Austria)atthestartandendofthe30-mtrack. During these trials the women wore a portable telemet- ric metabolic cart, a chest belt that monitored heart rate, and a portable near-infrared spectroscope (NIRS). Blood samples and ratings of perceived exertion were obtained at the same point in each cycle of sprinting (Figure 1). Design of sub-study 2 All athletes in sub-study 2 (n = 12; age: 23 ± 2 yrs; height: 169 ± 3 cm; body mass: 61 ± 6 kg; fat mass: 17 ± 4% (mean ± SD)) carried out the same procedure as in sub-study 1, but wore instead a telemetric device to record muscle activation during the repeated sprinting. In this case motion was captured by video-analysis. The compression garment with adhesive silicone stripes
± 2 yrs; height: 169 ± 3 cm; body mass: 61 ± 6 kg; fat mass: 17 ± 4% (mean ± SD)) carried out the same procedure as in sub-study 1, but wore instead a telemetric device to record muscle activation during the repeated sprinting. In this case motion was captured by video-analysis. The compression garment with adhesive silicone stripes The CGSS consisted of tights extending from the waist to the ankle with adhesive stripes of silicone on the inner lining designed to compress the anterior and posterior thighs, as well as lower legs, in accordance with previous guidelines [21] (Figure 2). Before the sprints, the levels of compression on the skin by this garment at them. gluteusmaximus,m.rectusfemoris,m.vastuslateralis, m. biceps femorisandm. gastrocnemius medialiswere determined three times in accordance with international recommendations employing a pneumatic sensor (SIGaT®, Ganzoni-Sigvaris, St. Gallen, Switzerland) [22], as de- scribed previously [23,24]. Data collection In sub-study 1 gas exchange and heart rate were moni- tored continuously with a portable breath-by-breath gas analyzer (Metamax 3B, Cortex, Leipzig, Germany) and a chest belt (Polar T31, 1 Hz, Polar Electro Oy, Kempele, Finland), respectively. The gas analyzer used standard algorithms to account for the time delay between in- spiration and expiration and to calculate the oxygen consumption. The volume was calibrated using a syringe with a volume of exactly 3 L (Cortex, Leipzig, Germany). The anticipated range of fractional gas concentrations was Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 Page 2 of 9 http://biomedcentral.com/2052-1847/6/21
calibrated before each trial with 15.8% O 2and 5% CO 2 in N 2(Praxiar Technology Inc., Danbury, CT, USA). A Hans-Rudolph mask was used to attach the turbine flowmeter and all tubes and cables were fixed in place with tape and straps to assure that the athletes could move freely. For determination of alternations in muscle oxygenation and blood volume, a wireless NIRS (Portamon, Artinis Medical System, Zetten, The Netherlands) was attached with adhesive tape between the lateral femoral epicondyle and the greater trochanter of the femur across the maximum girth of the belly of the rightvastus lateralis muscle. None of the participants reported discomfort or disturbance of their normal pattern of movement by any of the devices attached. Since the pattern of oxygen- ation within thevastus lateralismuscle is not uniform, the location of the NIRS during the first trial was indicated with a permanent marker to ensure the same placement during the second set of 30 30-m sprints [25]. The NIRS weighed 85 g and measured 83 × 52 × 20 mm, with distances of 30, 35 and 40 mm between the three light sources and the optical detector. Changes in the oxygenated and deoxygenated levels of hemoglobin (Hb) plus myo- globin (Mb) were monitored at 760 and 890 nm, respect- ively [26]. In addition, local blood volume was determined on the basis of total hemoglobin (tHb), as indicated by the sum of these signals. The tissue saturation index [%] (TSI %), reflecting the relationship between oxygen delivery and consumption, was calculated as [[HbO 2]/([HbO 2]+ [HHB)] × 100. At the same point in each cycle of sprinting, capillary blood was sampled from the right earlobe for determin- ation of the lactate concentration by amperometric- enzymatic analysis (Ebio Plus, Eppendorf AG, Hamburg, Figure 1Schematic illustration of the repeated sprint protocol. Figure 2Schematic illustration of the CGSS with placement of the silicone stripes on the anterior and posterior leg (a) and detailed structure of the adhesive silicone stripes on the inner lining of the garment (b). Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 Page 3 of 9 http://biomedcentral.com/2052-1847/6/21
Eppendorf AG, Hamburg, Figure 1Schematic illustration of the repeated sprint protocol. Figure 2Schematic illustration of the CGSS with placement of the silicone stripes on the anterior and posterior leg (a) and detailed structure of the adhesive silicone stripes on the inner lining of the garment (b). Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 Page 3 of 9 http://biomedcentral.com/2052-1847/6/21
Germany) and subjective ratings of perceived exertion by the whole body, upper leg muscles (including the gluteal muscles) and lower leg muscles were made on Borg’s 6–20 scale [27]. Skin temperature on the anterior thigh was determined (MSR Modular Signal Recorder, Prospective Concepts AG, Glattbrugg, Switzerland) both before and after each set of sprints to ensure equal thermo- regulatory conditions for both sets. In sub-study 2 each sprint was recorded with a high- speed camera at a sampling rate of 120 Hz (GoPro, San Mateo, CA, USA) and the kinematic data collected ana- lyzed digitally (Kinovea®, version 0.8.15, Bordeaux, France). This camera was placed 11.5 m away from and at a right angle to a point 28 m along the running track (Figure 1). Markers were attached to the athlete’s greater trochanter, medial and lateral femoral epicondyles, as well as to both the medial and lateral forefoot. As previously, markers were fixed to the garment in order not to interfere with its compression properties [28]. To determine step frequency, a second camera was positioned at the end of the running track, 1.5 m to the side of the finish gate to record each step. The number of steps taken during each sprint was counted and divided by the sprint time to obtain step fre- quency, as described previously [29]. Surface electromyographic activity (EMG) was measured on the right side of the body utilizing pre-gelled bipolar AgCl electrodes (Blue Sensor N, Ambu A/S, Ballerup, Denmark). After shaving, abrading, and disinfecting the skin, these electrodes were attached parallel to the muscle fibers on the skin of the bellies of thegluteus maximus, rectus femoris, vastus lateralis, biceps femoris,andgastro- cnemius medialismuscles. A reference electrode was attached to the tibial bone and all positioning was as recommended by Hermens and Hermie [30]. All signals were transferred to the computer by an analog-to-digital converter card (DAQ 700 A/D card, National Instruments, Austin, TX, USA), differentially amplified and stored in real time by a telemetric recording system (EMG, TeleMyo2400T, Noraxon Inc., Scottdale, AZ, USA). The sampling rate was 1500 Hz. To erase low- and high- frequency noise,
as recommended by Hermens and Hermie [30]. All signals were transferred to the computer by an analog-to-digital converter card (DAQ 700 A/D card, National Instruments, Austin, TX, USA), differentially amplified and stored in real time by a telemetric recording system (EMG, TeleMyo2400T, Noraxon Inc., Scottdale, AZ, USA). The sampling rate was 1500 Hz. To erase low- and high- frequency noise, all raw signals were passed through a digital band-pass filter (10-500 Hz, 3 dB, Butterworth 2 nd edition). The signals were then rectified, smoothed (using the mean values for 50-ms time frames), and normalized to the fastest sprint, as recommended earlier [31]. The in- tegrated EMG (iEMG) was employed as an indicator of muscle activation. All of these analyses were performed with the MyoResearch program (Master Edition version 1.08.27, Noraxon Inc., Scottsdale, AZ, USA). Statistical analysis All data are presented as mean values (mean) ± standard deviations (SD). As decided in advance, we were inter- ested in comparing the CGSS and control conditions. After confirming normal distribution, the data from each set of repeated sprints were divided into three equal sub- sets (sprints 1-10, 11-20, and 21-30), these subsets aver- aged and data for CGSS and control condition compared using Student’spairedt-test. A difference with an alpha value ofP≤0.05 was considered to be statistically signifi- cant and then adjusted for multiple comparison with the conservative Bonferroni correction, as described previ- ously [32-34]. All of these analyses were performed with the Statistica software package for Windows (version 7.1, StatSoft Inc., Tulsa, OK, USA). To compare the practical relevance and meaningful- ness of the various findings, effect sizes were calculated using the conventional procedure proposed by Cohen [35]. Cohen’sdvalue was calculated by dividing the differ- ence between the means of the intervention and control trials by the average standard deviation for the subject population [35]. In the conventional manner, effect sizes of 0.20, 0.50 and 0.80 were regarded as small, medium and large, respectively [35]. Results Table 1 documents the pressure applied on the skin by the garment at the various sites on the body during both sub-studies. All physiological, biomechanical and performance
control trials by the average standard deviation for the subject population [35]. In the conventional manner, effect sizes of 0.20, 0.50 and 0.80 were regarded as small, medium and large, respectively [35]. Results Table 1 documents the pressure applied on the skin by the garment at the various sites on the body during both sub-studies. All physiological, biomechanical and performance values, as well as the level of statistical significance (P) and corresponding effect size (d)forall comparisons made, are presented in Table 2. Sub-study 1: Cardio-respiratory, metabolic, hemodynamic and perceptional variables during repeated sprinting Performance of the repeated 30 30-m sprints was im- proved during the final third of the protocol (sprints 21-30) by wearing the CGSS (P=0.02,d=0.37). Cardio- respiratory and metabolic values (bestP= 0.13, best d= 0.54), the tissue saturation index (bestP=0.27, d= 0.35), levels of oxy- (bestP=0.06,d= 0.71), deoxy- (bestP=0.25,d= 0.51) and total hemoglobin (bestP= 0.4,d= 0.44) as well as skin temperature (P=0.75,d= 0.18) were all unaffected by the use of this garment. Furthermore, during the final 10 sprints the CGSS reduced the perceived rating of exertion in the upper Table 1 The pressure exerted at various sites on the skin by the compression garment with adhesive silicone stripes Muscle Pressure [mmHg] (mean ± SD) Sub-study 1 (n = 12) Sub-study 2 (n = 12) Gluteus maximus 18.3 ± 4.1 20.2 ± 4.3 Rectus femoris 19.0 ± 4.9 20.2 ± 4.9 Vastus lateralis 17.5 ± 4.4 18.2 ± 4.1 Biceps femoris 19.6 ± 4.7 19.5 ± 5.6 Gastrocnemus medialis 21.7 ± 6.0 19.9 ± 5.6 Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 Page 4 of 9 http://biomedcentral.com/2052-1847/6/21
Table 2 Physiological, biomechanical and performance values (means ± SD) associated with the repeated sprints with and without the compression garm ent with adhesive silicone stripes (CGSS) Variable Sprints 01-10 Sprints 11-20 Sprints 21-30 CGSS ControlPvalue ESdCGSS Control P value ESdCGSS Control P value ESd Sub-study 1 (n = 12) Time [s] 4.97 ± 0.21 5.00 ± 0.22 0.28 0.22 5.09 ± 0.29 5.12 ± 0.29 0.09 0.14 5.12 ± 0.29 5.21 ± 0.34 0.02 0.37 Oxygen uptake [mL∙min -1 ] 2.51 ± 0.53 2.45 ± 0.48 0.47 0.17 2.62 ± 0.63 2.65 ± 0.64 0.77 0.08 2.59 ± 0.6 2.63 ± 0.64 0.71 0.09 Ventilation [L∙min -1 ] 69.1 ± 9.9 68.3 ± 12.6 0.68 0.1 76.5 ± 7.1 78 ± 10.5 0.53 0.23 77.3 ± 8.3 79.1 ± 9.1 0.3 0.31 Heart rate [bpm] 169 ± 7.5 169 ± 7.5 0.92 0.04 178 ± 8.2 177 ± 5.5 0.59 0.2 177 ± 8.5 178 ± 7.2 0.45 0.2 Blood lactate [mmol∙L -1 ] 5.53 ± 1.54 6.17 ± 2.03 0.13 0.5 6.55 ± 1.92 7.29 ± 1.9 0.16 0.54 6.46 ± 2.03 6.84 ± 1.74 0.45 0.29 Tissue saturation index [%] 93.3 ± 3 92.9 ± 3.9 0.68 0.14 91.2 ± 3.4 92.2 ± 4 0.27 0.35 90.7 ± 3.5 91.5 ± 4.6 0.34 0.27 Oxy-hemoglobin [μM∙cm] 101 ± 10.8 95 ± 10.4 0.06 0.71 108 ± 14.5 107 ± 17.2 0.8 0.08 109 ± 15.7 110 ± 22.6 0.83 0.07 Deoxy-hemoglobin [μM∙cm] 108 ± 6.3 108 ± 7.7 0.87 0.06 113 ± 7.7 116 ± 11.7 0.26 0.42 114 ± 8.7 119 ± 16.9 0.25 0.51 Total hemoglobin [μM∙cm] 103 ± 7.2 100 ± 8 0.4 0.44 109 ± 8.7 111 ± 14.4 0.61 0.21 110 ± 9.5 113 ± 20 0.41 0.33 Rating of perceived exertion [Borg ’s Scale] Whole-body 10 ± 2.3 10 ± 2.3 0.98 0.01 14.6 ± 2.2 15.4 ± 1.9 0.09 0.58 17.6 ± 2.3 18.5 ± 1.3 0.13 0.68 Upper leg muscles 9.5 ± 2.7 10.4 ± 2.5 0.29 0.49 13 ± 3.3 14.9 ± 1.7 0.04 1.0 15.7 ± 3.2
9.5 113 ± 20 0.41 0.33 Rating of perceived exertion [Borg ’s Scale] Whole-body 10 ± 2.3 10 ± 2.3 0.98 0.01 14.6 ± 2.2 15.4 ± 1.9 0.09 0.58 17.6 ± 2.3 18.5 ± 1.3 0.13 0.68 Upper leg muscles 9.5 ± 2.7 10.4 ± 2.5 0.29 0.49 13 ± 3.3 14.9 ± 1.7 0.04 1.0 15.7 ± 3.2 17.7 ± 1.9 0.01 1.1 Lower leg muscles 8.6 ± 2.3 8.3 ± 2.3 0.5 0.19 11.4 ± 3.2 11.7 ± 3.2 0.58 0.12 13.6 ± 3.7 14 ± 4 0.64 0.15 Sub-study 2 (n = 12) Time [s] 4.87 ± 0.31 4.88 ± 0.39 0.73 0.07 4.88 ± 0.31 4.95 ± 0.40 0.08 0.25 4.85 ± 0.31 4.99 ± 0.36 <0.01 0.61 Hip flexion angle [°] 95.3 ± 4.6 102.8 ± 7.5 <0.01 1.69 96.4 ± 6.3 106.7 ± 6.4 <0.01 2.28 98.4 ± 6.4 106.3 ± 6.1 <0.01 1.78 Step length [m] 2.24 ± 0.1 2.17 ± 0.13 0.03 0.85 2.23 ± 0.13 2.16 ± 0.16 0.07 0.61 2.24 ± 0.14 2.14 ± 0.17 0.01 0.91 Step frequency [Hz] 3.66 ± 0.23 3.65 ± 0.21 0.78 0.08 3.64 ± 0.23 3.65 ± 0.26 0.91 0.03 3.66 ± 0.24 3.63 ± 0.26 0.34 0.2 iEMG [%] Gluteus maximus91.8 ± 11.8 81.7 ± 13.3 0.04 1.14 91.5 ± 28.3 83.5 ± 19.6 0.37 0.46 93.9 ± 31.9 79.2 ± 14 0.13 0.84 Rectus femoris92.7 ± 12.6 96.7 ± 13.5 0.36 0.44 91.1 ± 11 86.8 ± 15.5 0.5 0.45 95.4 ± 18.5 78.9 ± 19.2 0.01 1.24 Vastus lateralis88.6 ± 14.7 84.2 ± 6.5 0.31 0.55 89.8 ± 19.9 85.1 ± 13.1 0.53 0.39 95.1 ± 23.9 84.7 ± 10.6 0.23 0.8 Biceps femoris91.3 ± 21.8 90.3 ± 6.3 0.88 0.08 87.7 ± 19.3 85.8 ± 13.8 0.79 0.16 92.1 ± 24.4 83.8 ± 15.5 0.32 0.58 Gastrocnemius medialis88.8 ± 18.7 86.5 ± 13.4 0.63 0.21 92 ± 28.7 89.8 ± 15.5 0.79 0.13 96.2 ± 39.5 102.4 ± 24.5 0.65 0.26 Abbreviations. iEMG, integrated EMG; ES, Effect size. Bornet al. BMC Sports Science, Medicine, and Rehabilitation2014,6:21 Page 5 of
Description
The study investigates the effects of a novel compression garment on repeated sprint performance.