Effects of 24 h Compression Interventions with Different Garments on Recovery Markers during Running

ssion and temperature manipulation are discussed as strategies to improve perfor- mance markers and recovery in sports. Here, we investigate the effects of compression stockings made with fabric, either combined or not with heating and cooling substances, on variables related to running performance and recovery. Ten trained runners (mean standard deviation age45 9 years old, body mass 69 7 kg, height 166 4 cm) with no experience of using compression garments performed an intense running session of 10 km, then wore a stocking for 24 h (randomized; without compression, compression, compression with camphor, and compression with menthol), and were evaluated on the following day, after running 5 km. The different types of compression stockings used 24 h before exercise did not affect running kinematics (p> 0.14), skin temperature (p> 0.05), heart

performed an intense running session of 10 km, then wore a stocking for 24 h (randomized; without compression, compression, compression with camphor, and compression with menthol), and were evaluated on the following day, after running 5 km. The different types of compression stockings used 24 h before exercise did not affect running kinematics (p> 0.14), skin temperature (p> 0.05), heart rate (p> 0.12; mean value of maximal heart rate 156 bpm), comfort perception (p= 0.13; mean value of 7/10 points), or perception of recovery (p= 0.13; mean value of 7/10 points). In general, there were no effects of 24 h pre-exercise lower leg compression, including those treated with menthol and camphor applications on running kinematics, skin temperature, heart rate, or recovery perception in athletes undertaking consecutive running exercises. Keywords: kinematics; compressive garment; skin temperature; exercise recovery; menthol; camphor 1. Introduction Athletes are interested in compression garments to improve athletic capacity and exercise recovery, but there is still a lack of evidence regarding their biomechanics and comforting effects. While compression can affect muscle soreness, muscle damage and in ammatory markers, performance, fatigue, and thermoregulation markers are usually unaltered [1]. Biomechanic parameters, and more interestingly, athletes' beliefs, underline the importance of including a placebo when assessing compression effects [2]. Previous studies investigating the lower extremity biomechanics in participants subject to compression showed controversial results. Hip and thigh compression may in uence the performance of jump landing tasks due to decreased dynamic valgus in the landing [3] and reduced sagittal plane range of motion for the hip joint [4]. Such results have been reported as dependent on reduced muscle oscillation, improved force production [5], and joint stiffness [6]. More importantly, previous studies suggested a compression effect on important kinematics characteristics of articular movements. Theoretically, these effects could also be interpreted as useful for injury prevention. Life2021,11, 905.

Life2021,11, 905 2 of 12 The effects of compression on running performance parameters have attracted the interest of scientists, but knowledge about their effects on running kinematics, for example, is limited. Moreover, evidence to support the claim of below-knee compression garments in improving recovery in runners is also limited [2]. The mechanisms explaining the effects of compression remain unclear, mainly being discussed as dependent on changes in blood ow and oxygen delivery [7], reduced muscle oscillation and muscle activation [8], and the in uence of an athlete's beliefs about the bene ts of compression [2]. For two consecutive 5 km running sessions with a 1 h recovery period, wearing compression stockings in between did not in uence performance time and rate of fatigue. When the same participants were grouped according to their perception of the ef cacy of compression stockings (being classi ed as believers or not), the runners with a stronger belief in the effects of compression showed improved running performance after 1 h compression compared to those with a neutral or negative perception of compression effects [9]. When 4 h compression was administrated during and after intense running, there were bene cial trends in performance and reduced muscle soreness in the following 24 h post-exercise period [10]. Soccer athletes also reported reduced perception of muscle soreness under conditions of cumulative exercise and use of compression garments [11]. The effects of a more extended period of compression are still debatable. During recovery, positive effects of 24 h compression were found in cyclists completing two consecutive time trials [12]. They achieved a 3.3% improvement in power output after compression without changes in the rate of perceived effort and oxygen uptake [12]. Similar outcomes were described for shorter sessions of high-intensity cycling, in which compression was applied during the recovery period [13]. Considering that different studies report different responses to compressive garments, outcomes are often discussed as dependent on blood ow and oxygenation, and there- fore body temperature could play a role. For example, manipulating temperature is a physiological strategy for improving muscle contraction, which helps to explain why a warming-up

cycling, in which compression was applied during the recovery period [13]. Considering that different studies report different responses to compressive garments, outcomes are often discussed as dependent on blood ow and oxygenation, and there- fore body temperature could play a role. For example, manipulating temperature is a physiological strategy for improving muscle contraction, which helps to explain why a warming-up period before exercise can bene t performance [14]. The use of a garment promoting heating could reinforce this mechanism. Before and during warming-up, skin cooling also seems to improve exercise performance [15]. Ice ingestion, for instance, has been used as an internal cooling strategy to improve running performance parameters [16]. It is challenging to combine temperature manipulations while delivering compression. One option is to use chemical compounds combined with the textile material. A compres- sion fabric with menthol application promotes the perception of freshness and reduces heating discomfort [17]. On the other hand, camphor initially induces a perception of coolness that changes to heat stimulation, so presenting effects on blood circulation and performance, similar to that of the menthol application [18]. Therefore, compression gar- ments combined with these compounds could promote an additional stimulus by eliciting changes in the local temperature of the skin and muscles. In this study, we determine the effects of pre-exercise lower leg compression, either combined or not with heating and cooling substances, on variables related to running recovery when performing intense exercise on two consecutive days. We hypothesized that different compression garments administrated during the 24 h recovery period, including those with the application of chemical compounds such as menthol and camphor, could positively in uence biomechan- ics' characteristics of running technique, heart rate, and recovery markers on consecutive days of running. Such a positive in uence would translate into similar or better outcomes when the compression conditions were compared with the control condition. 2. Materials and Methods 2.1. Participants and Experimental Design The research was advertised in local running clubs, and experienced runners were invited to join the experiment. They were invited to visit the laboratory eight times within 12 weeks when no competition

in uence would translate into similar or better outcomes when the compression conditions were compared with the control condition. 2. Materials and Methods 2.1. Participants and Experimental Design The research was advertised in local running clubs, and experienced runners were invited to join the experiment. They were invited to visit the laboratory eight times within 12 weeks when no competition was scheduled. The eight visits always included a block of two consecutive days of indoor running, one for each of the control or compression

Life2021,11, 905 3 of 12 garment conditions. We were able to include ten experienced male competitive runners in the study. They had mean standard deviation age 45 9 years old, body mass69 7 kg , height166 4 cm , and have frequently been training over the past 14 13 years, with a 5 km personal record of 20:13 3:54 min (fastest participant: 18:05 min; slowest participant: 23:00 min). All participants were members of running clubs from the local community, had been training and running for at least one year uninterruptedly, had no history of injury or pain, had participated in amateur competitive events with distances from 5 to 42 km, and did not have any previous experience of using compression. Participants not completing all the evaluation sessions in the expected period of 12 weeks were excluded. The participants had never worn leg compression garments before and did not classify themselves as believers in compression effects during an interview, which included ques- tions such as “do you know what compression garments are?” and “do you believe they can improve performance during running?” The local institution ethics committee approved this research, and all participants signed a consent term. All procedures complied with the Helsinki declaration. Compression and control garment conditions were randomized. On day 1, participants ran 10 km at their competitive pace. On day 2, they ran 5 km at the same speed as day 1, and the data were collected. Garments were provided after the end of exercise on day 1 and worn continuously for the following 24 h. Each garment condition was evaluated at least one week apart, and participants always used the same shoes. Running was performed without the garments. FigureLife 2021, 11, 905 3 of 12 2. Materials and Methods 2.1. Participants and Experimental Design The research was advertised in local running clubs, and experienced runners were invited to join the experiment. They were invited to visit the laboratory eight times within 12 weeks when no competition was scheduled. The eight visits always included a block of two consecutive days of indoor running, one for each of

Materials and Methods 2.1. Participants and Experimental Design The research was advertised in local running clubs, and experienced runners were invited to join the experiment. They were invited to visit the laboratory eight times within 12 weeks when no competition was scheduled. The eight visits always included a block of two consecutive days of indoor running, one for each of the control or compression garment conditions. We were able to include ten experienced male competitive runners in the study. They had mean ± standard deviation age 45 ± 9 years old, body mass 69 ± 7 kg, height 166 ± 4 cm, and have frequently been training over the past 14 ± 13 years, with a 5 km personal record of 20:13 ± 3:54 min (fastest participant: 18:05 min; slowest partici- pant: 23:00 min). All participants were members of running clubs from the local commu- nity, had been training and running for at least one year uninterruptedly, had no history of injury or pain, had participated in amateur competitive events with distances from 5 to 42 km, and did not have any previous experience of using compression. Participants not completing all the evaluation sessions in the expected period of 12 weeks were excluded. The participants had never worn leg compression garments before and did not classify themselves as believers in compression effects during an interview, which included ques- tions such as “do you know what compression garments are?” and “do you believe they can improve performance during running?” The local institution ethics committee ap- proved this research, and all participants signed a consent term. All procedures complied with the Helsinki declaration. Compression and control garment conditions were randomized. On day 1, partici- pants ran 10 km at their competitive pace. On day 2, they ran 5 km at the same speed as day 1, and the data were collected. Garments were provided after the end of exercise on day 1 and worn continuously for the following 24 h. Each garment condition was evalu- ated at least one week apart, and participants always used the same shoes. Running was performed without

On day 2, they ran 5 km at the same speed as day 1, and the data were collected. Garments were provided after the end of exercise on day 1 and worn continuously for the following 24 h. Each garment condition was evalu- ated at least one week apart, and participants always used the same shoes. Running was performed without the garments. Figure 1 shows the experimental design. Figure 1. Experimental design. All participants ran day 1 without the control or compressive garment. After the running exercise, they wore the garments for 24 h before returning to the laboratory for assessment on day 2. As we tested one control and three compression conditions, each participant repeated the protocol four times. 2.2. Compression Stockings Four different garments were considered. They were all long socks from the knee popliteal line to the foot. The compression garments were stockings made of 10% polyam- ide, 75% polyester, and 15% elastomer. Three compression models were used as the stand- ard and two others that included camphor and menthol to induce the perception of hot and cold. The garments’ compression was gradual, with an average of 21–24 mmHg pres- sure reported by the manufacturer. A finishing textile process in a padding machine ap- plied camphor and menthol; the concentration of the solution was: 7% of the respective substance (camphor or menthol), 3% of polyvinyl pyrrolidone (PVP), 35% of ethanol, and Figure 1. Experimental design. All participants ran day 1 without the control or compressive garment. After the running exercise, they wore the garments for 24 h before returning to the laboratory for assessment on day 2. As we tested one control and three compression conditions, each participant repeated the protocol four times. 2.2. Compression Stockings Four different garments were considered. They were all long socks from the knee popliteal line to the foot. The compression garments were stockings made of 10% polyamide, 75% polyester, and 15% elastomer. Three compression models were used as the standard and two others that included camphor and menthol to induce the perception of hot and cold. The garments' compression was gradual,

different garments were considered. They were all long socks from the knee popliteal line to the foot. The compression garments were stockings made of 10% polyamide, 75% polyester, and 15% elastomer. Three compression models were used as the standard and two others that included camphor and menthol to induce the perception of hot and cold. The garments' compression was gradual, with an average of 21–24 mmHg pressure reported by the manufacturer. A nishing textile process in a padding machine applied camphor and menthol; the concentration of the solution was: 7% of the respective sub- stance (camphor or menthol), 3% of polyvinyl pyrrolidone (PVP), 35% of ethanol, and 55% of water. After impregnation, the garments were dried for polymerization. The control stocking was a model of the same color and size but made of 100% cotton. Cotton socks are standard for a runner, and we therefore considered it as a control. The purpose of com- pression garments is to promote greater compression than cotton socks. All the stockings were brand new, from the same manufacturer, and had identical designs and appearance.

Life2021,11, 905 4 of 12 Sizes were adjusted for each participant considering leg circumference and according to the manufacturer's sizing chart. 2.3. Running Protocols Running was performed on a motorized treadmill with control for speed and inclina- tion set at 1% (Gait Trainer 3, Biodex Inc., Shirley, NY, USA). Running was performed at a competitive race pace corresponding to 90% of the best 10 km personal record [9]. A warm- up was conducted before the protocol by walking 3 min at 1.4 m/s, followed by 3 min running at 2.2 m/s. The average running speed for the running sessions was3.5 0.2 m/s . After completing 10 km, the athletes received a garment and wore it for 24 h until they returned to the lab for assessment on day 2. They were requested to take the garment off only for showering and not to perform any recovery strategy. On day 2, the 5 km running protocol was performed at the same individual speed as day 1, without garments, and kinematic, perception, and skin temperature measurements were undertaken. 2.4. Kinematic Assessment Trunk, hip, knee, and ankle sagittal plane angles determined at the foot strike instant, step frequency, and step length were determined by 2D video analysis [19]. Measurements were taken at the 1st, 3rd, and 5th kilometers of the 5 km run on day 2 with a video camera placed aside the treadmill with the lens perpendicular to the plane of movement. The camera was positioned on a tripod of 90 cm height and 3 m away from the volume of movement. Movements were recorded at 30 Hz and further de-interlaced to 60 Hz using a motion analysis tool (Kinovea 0.8.15-https://kinovea.org, accessed on 6 July 2021). Spherical re exive markers of 14 mm diameter were placed on the shoe at the fth metatarsal, lateral malleolus, lateral knee epicondyle, great trochanter, and acromion on the right side of the body. Joint angles were de ned in the sagittal at the foot strike as illustrated in Figure 3 (trunk angle de ned according to the vertical axis, hip angle de ned according to the

mm diameter were placed on the shoe at the fth metatarsal, lateral malleolus, lateral knee epicondyle, great trochanter, and acromion on the right side of the body. Joint angles were de ned in the sagittal at the foot strike as illustrated in Figure 3 (trunk angle de ned according to the vertical axis, hip angle de ned according to the horizontal axis, relative angles for knee and ankle, see Figure 3). Ten complete strides were analyzed for each kilometer considered [19]. All participants presented a rear strike landing pattern. 2.5. Analysis of Heart Rate, Comfort, and Perceived Recovery On day 2, participants were questioned about their perception of recovery regarding the exercise performed the day before. The perception of recovery was assessed considering a visual scale ranging from 0 (very poorly recovered/extremely tired) to 10 (very well recovered/highly energetic) [20]. For both days, heart rate during running was monitored every second using a heart monitor (F50, Polar Electro Oy, Espoo, Uusimaa, Finland), and the data were averaged over each minute of the running session, excluding the warm-up period. The highest heart rate (HR) value was then considered for the statistics. The perception of comfort in wearing the stockings was assessed through an adapted analog visual scale [21] when participants arrived at the laboratory on day 2. The scale ranged from uncomfortable (0 cm) to the most comfortable condition imaginable (10 cm). The comfort parameters analyzed were general comfort in wearing the garment, comfort perception as regards the feel on touching the fabric material, perceived calf compression, humidity, and perceived temperature. An average score was determined to represent the overall comfort. We preferred to use the heart rate instead of the rate of perceived effort (Borg Scale) to describe exercise intensity given that two other visual analog scales were already being used to monitor recovery and comfort. Heart rate, comfort, and perceived recovery were averaged across the participants for assessing the different garments. 2.6. Skin Temperature Skin temperature was determined before and immediately after each running session using a thermal infrared camera (E-60, 320 240 pixels, FLIR Systems Inc., Wilsonville, OR,

given that two other visual analog scales were already being used to monitor recovery and comfort. Heart rate, comfort, and perceived recovery were averaged across the participants for assessing the different garments. 2.6. Skin Temperature Skin temperature was determined before and immediately after each running session using a thermal infrared camera (E-60, 320 240 pixels, FLIR Systems Inc., Wilsonville, OR, USA) with Noise Equivalent Temperature Difference (NETD) < 0.05 C, and measurement

The study investigates the effects of compression garments on recovery markers in trained runners.