Studies show that textile fibers also delay muscle fatigue
A line of textile fibers commercially called Emana, used in clothing, is capable of improving blood microcirculation and delaying muscle fatigue. Previous research has shown that clothing with this fiber increases skin elasticity and reduces signs of cellulite when worn for a certain period of time. Already in the sportswear segment there was evidence that Emana could help athletes reduce muscle fatigue and increase aerobic performance. This fact was proven by three studies developed by physical education professional and researcher Arthur Fernandes Gáspari at the Exercise Physiology Laboratory of the Faculty of Physical Education (FEF) at Unicamp. The studies were supervised by professor Antonio Carlos de Moraes, from the Department of Sports Sciences at FEF.
The Emana thread, created in 2009, absorbs part of the energy originating from the environment and the human body itself, such as heat, and returns it with infrared radiation characteristics, which penetrates the body more deeply and stimulates local microcirculation and energy metabolism, reducing fatigue and muscle pain. This effect is achieved by introducing into the polyamide yarn, the yarn's polymeric matrix, bioactive mineral crystals that have the property of absorbing energy and redirecting it to the long infrared region (IVL), consisting of waves of greater length and consequently lower energy between those in the infrared band, which are distinguished by not causing a significant increase in temperature.
Professor Antonio Carlos recalls that studies of the effect of IVL-emitting fabric on physical performance began at FEF in mid-2012, with the establishment of a research agreement between Rhodia, part of the Solvay group, manufacturer of the fibers and holder of the patent for the Emana fabric, and Unicamp. During its validity, two exploratory protocols were developed to investigate possible effects of the tissue: one aimed at aerobic performance – long-term exercise limited by the individual's resistance – and another aimed at verifying the tissue's potential to reduce muscle damage and accelerate recovery. after strenuous exercise. The IVL results on aerobic performance, although interesting, were not conclusive and suggested further research. Hence the idea of the doctoral project developed by Arthur that Rhodia, even after the end of the agreement, supported through the donation of materials.
The project's main focus was to investigate the effects of a suit (pants) made with polyamide yarn, co-produced with IVL-emitting ceramic nanoparticles, on predominantly aerobic exercise performance and the physiological mechanisms related to this possible effect. We also checked the temperature variation in the body area irradiated with IVL, as its increase during exercise would compromise performance.
Although infrared is one of the radiations normally ignored from the sun, its beneficial effects as a vasodilator and antioxidant are known, its contribution to the increase in the production of nitric oxide (NO) – a key molecule in a series of biological functions –, in the enhancement of function of some cells and delaying fatigue in skeletal muscles. For the professor, the research carried out is justified because the effects of this source of IVL on human physiology and its ergogenic potential on physical performance are little known, measured by the material or chemical strategies used with the aim of improving sports performance and accelerating the post-exercise recovery.
Three aspects
The investigations were carried out in three aspects. The first aimed to confirm the possible beneficial effects of IVL tissue on physical performance and verify whether some of the physiological mechanisms already described in the literature could explain the results found. In this phase, in which 14 young, active male volunteers participated, the effects of IVL on intense cycling exercise, up to physical exhaustion, were analyzed, measuring changes in temperature, increased energy production via aerobic routes, reduced oxidative stress and increased availability of nitric oxide.
Each subject underwent testing using IVL and placebo fabric pants in crossed order (cross-over), with identical fabrications, appearances and consistencies, provided by the manufacturer without even the researchers being able to identify them (double-blind). Participants wore the pants for a week before the tests, carried out at appropriate intervals to eliminate interference.
The results showed that the IVL-emitting tissue increased the exercise time to exhaustion by 25%. Greater energy production through aerobic metabolism and lower oxidative stress were also observed, without changes in temperature, antioxidant defense markers and nitric oxide bioavailability, contradicting the initial hypothesis that NO would be responsible for the ergogenic effect. The use of the fabric therefore contributed to increasing physical performance in this type of exercise and suggests its efficiency in improving energy production. However, the lack of increase in NO bioavailability, which could contribute to the positive action of IVL, raised a question: what would be the biochemical mechanism resulting from the effects of this radiation? This question led to the second aspect of the study.
In this case, the objective was to explore the effects of IVL tissue on metabolic responses to aerobic exercise of different intensities, seeking to identify possible biochemical pathways that could explain the beneficial results of the tissue observed in the previous study. The same protocols were maintained for a similar population, consisting of 20 men, now undergoing continuous cycling exercises at low and high intensity and blood samples collected with a view to investigating changes in the metabolomic profile - which allows a broad localization of the system's metabolites. biological – and in energy metabolism.
The results showed a 23% increase in performance and an improvement in energy production, corroborating the findings of the previous study. Furthermore, 55 metabolites were identified, common to all blood samples collected, which made it possible to determine the biochemical pathways of energy production as the most important for the effect of IVL tissue. The molecules found in this scan pointed to two possible paths: improving mitochondrial efficiency, the cellular organelle responsible for producing energy through oxygen, and increasing lipolysis, the breakdown of fat molecules stored in adipose tissue that enter the current and are used as fuel for muscle tissue. These findings show the possible mechanisms of IVL action in the body that result in increased aerobic performance.
The positive effects on physical performance identified in these first two studies were concentrated in amateur cyclists. It still remained to be seen whether the results would also prevail in high-performance athletes, who would possibly show a lower degree of response to the effects of IVL radiation due to the already high adaptation to exercise.
Furthermore, recalls Arthur, the two previous studies aimed to test the potential of IVL tissue in delaying fatigue, increasing the time that individuals can maintain exercise, which is excellent for investigating the increase in resistance and the possible mechanisms physiological and biochemical factors involved, but are far from the demands of sport. By the way, he says: “In the real world, in conventional sporting events, athletes have the task of covering a certain distance in the shortest possible time, like running or cycling”. In view of this, the third aspect of the study, which included 11 participants, focused on verifying the effectiveness of IVL fabric in improving highly trained cyclists in a four km time trial.
The results indicated an improvement in performance of 2,2s and 3,5s (which corresponds to approximately 1,5%) when comparing, respectively, the results between IVL fabric and placebo and standard clothing. It was even found that the reduction in time to complete the four km test with the IVL was greater than the error associated with the measurement itself, confirming the positive effect also for this population and test. Although discreet, the variation is relevant for high-performance athletes, as it can determine whether they reach the podium, emphasizes the researcher.
For him, the results achieved in these three studies show the ergogenic effect of IVL fabric in improving performance in aerobic endurance tests for active and trained individuals. They also suggest that the possible mechanism of action of IVL is associated with increased energy production via aerobic routes and that its positive effects on the body, which result in improved performance, are associated with both muscle and adipose tissue, which opens up path for new research.
Multidisciplinary character
The course of the study was very broad and involved several partnerships, since its conception, with the co-guidance of professor Romulo Cassio de Moraes Bertuzzi, from the Aerobic Performance Study Group at USP, who had an active participation in the construction of the protocols and in the discussion of the results. Performance tests, temperature measurements, biochemical analyzes and energy metabolism were carried out at the Exercise Physiology Laboratory (FISEX – Unicamp) under the supervision of professor Mara Patricia T. Chacon-Mikahil. The analyzes to determine the bioavailability of nitric oxide were carried out at Aterolab-Unicamp, at the Faculty of Medical Sciences, supervised by professor Andrei Carvalho Sposito.
At the National Biosciences Laboratory of the National Center for Research in Energy and Materials (LNBio/CNPEN), metabolomic analyzes were carried out, supervised by researcher Mauricio Sforza. The sandwich doctorate took Arthur to the University of Queensland, Brisbane, Australia, and Victoria University, Melbourne, Australia, where analyzes of all biochemical markers of oxidative stress and antioxidant defense were carried out.