Effects of far infrared rays emitting clothing on recovery after an intense plyometric exercise bout applied to elite soccer players: a randomized double-blind placebo-controlled trial

Enhanced far infrared emissivity, UV protection and near-infrared shielding of polypropylene composites via incorporation of natural mineral for functional fabric development

Far infrared radiation in the range of 4-20 µm has been showed to have biological and health benefits to the human body. Therefore, incorporating far-infrared emissivity additives into polymers and/or fabrics hold promise for the development of functional textiles. In this study, we incorporated nine types of natural minerals into polypropylene (PP) film and examined their properties to identify potential candidates for functional textiles and apparels. The addition of 2% mineral powders into PP film increased the far-infrared emissivity (5-14 µm) by 7.65%-14.48%. The improvement in far-infrared emissivity within the range of 5-14 µm, which overlaps with the peak range of human skin radiation at 8-14 µm, results in increased absorption efficiency, and have the potential to enhance thermal and biological effects. Moreover, the incorporation of mineral powders in PP films exhibited favorable ultraviolet (UV) protection and near-infrared (NIR) shielding properties. Two films, specifically those containing red ochre and hematite, demonstrated excellent UV protection with a UPF rating of 50+ and blocked 99.92% and 98.73% of UV radiation, respectively. Additionally, they showed 95.2% and 93.2% NIR shielding properties, compared to 54.1% NIR shielding properties of PP blank films. The UV protection and NIR shielding properties offered additional advantages for the utilization of polymer composite with additives in the development of sportswear and other outdoor garments. The incorporation of minerals could absorb near-IR radiation and re-emit them at longer wavelength in the mid-IR region. Furthermore, the incorporation of minerals significantly improved the heat retention of PP films under same heat radiation treatment. Notably, films with red ochre and hematite exhibited a dramatic temperature increase, reaching 2.5 and 3.2 times the temperature increase of PP films under same heat radiation treatment, respectively (46.8 °C and 59.9 °C higher than the temperature increase of 20.9 °C in the PP film). Films with additives also demonstrated lower thermal effusivity than PP blank films, indicating superior heat insulation properties. Therefore, polypropylene films with mineral additives, particularly those containing red ochre and hematite, showed remarkable heat capacity, UV-protection, NIR-shielding properties and enhanced far infrared emissivity, making them promising candidates for the development of functional textiles.

Physical properties and biological effects of ceramic materials emitting infrared radiation for pain, muscular activity, and musculoskeletal conditions

BACKGROUND

Up to 33% of the general population worldwide suffer musculoskeletal conditions, with low back pain being the single leading cause of disability globally. Multimodal therapeutic options are available to relieve the pain associated with muscular disorders, including physical, complementary, and pharmacological therapies. However, existing interventions are not disease modifying and have several limitations.

METHOD

Literature review.

RESULTS

In this context, the use of nonthermal infrared light delivered via patches, fabrics, and garments containing infrared-emitting bioceramic minerals have been investigated. Positive effects on muscular cells, muscular recovery, and reduced inflammation and pain have been reported both in preclinical and clinical studies. There are several hypotheses on how infrared may contribute to musculoskeletal pain relief, however, the full mechanism of action remains unclear. This article provides an overview of the physical characteristics of infrared radiation and its biological effects, focusing on those that could potentially explain the mechanism of action responsible for the relief of musculoskeletal pain.

CONCLUSIONS

Based on the current evidence, the following pathways have been considered: upregulation of endothelial nitric oxide synthase, increase in nitric oxide bioavailability, anti-inflammatory effects, and reduction in oxidative stress.

Effects of Far-Infrared Radiation-Lamp Therapy on Recovery From Simulated Soccer Match Running Activities in Elite Soccer Players

PURPOSE

The authors investigated whether far-infrared radiation (FIR) lamp therapy would reduce muscle damage and enhance recovery from multiple soccer-match-related running activities.

METHODS

Twenty-four elite female soccer players (20-24 y) were assigned into a FIR or a sham treatment group (n = 12/group). They performed a daily 90-minute Loughborough Intermittent Shuttle Test (LIST) for 6 consecutive days. Maximal voluntary contraction torque of the knee extensors (KEs) and flexors, muscle soreness, plasma creatine kinase activity, countermovement jump, and several other performance measures (eg, 30-m dash, Yo-Yo Intermittent Recovery Test Level 1) were taken before the first LIST, 1 hour after each LIST, and 24, 48, 72, 96, and 120 hours after the last LIST. All participants received a 30-minute FIR or sham treatment on KEs and knee flexors, respectively, at 2 hour after each LIST and 25, 49, 73, and 97 hours after the last LIST.

RESULTS

All measures changed significantly (P < .05) at 1 hour after the first LIST without difference (P > .05) between groups. Maximal voluntary contraction torque (eg, the largest decrease of KE for FIR: 13% [4%], sham: 25% [5%]), countermovement jump height (4% [3%] vs 14% [4%]), and other performance measures (eg, Yo-Yo Intermittent Recovery Test: 11% [5%] vs 26% [5%]) decreased less, and peak muscle soreness (eg, KE: 26 [9] vs 51 [18] mm) and plasma creatine kinase activity (172 [32] vs 1289 [610] IU/L) were smaller for the FIR than for the sham group (P < .05), and they returned to the baseline earlier (P < .05) for the FIR group.

CONCLUSIONS

These results suggest that the FIR therapy provided potent effects on reducing accumulated muscle damage and enhancing recovery.

Far-infrared-emitting fabric improves neuromuscular performance of knee extensor

The aim of this study was to verify if exposure to the far-IR emitted by fabric (FIR) is able to improve the neuromuscular performance of the knee extensors of resistance-trained males regardless of changes of the temperature. It is a crossover, randomized, double-blind, and placebo-controlled trial. Fourteen resistance-trained males (age: 24.3 ± 4 years; body mass: 82.8 ± 11.3 kg; height: 176.3 ± 4.2 cm) were randomly assigned to one of initial conditions: FIR (n = 7) or placebo (n = 7). After 4 days, the participants were submitted to neuromuscular tests in an isokinetic dynamometer (maximal isometric voluntary contraction (MVC) and fatigue test). After a week of washout, participants performed the other condition. We measured peak torque (Nm), total work (J), fatigue index (%), root mean square (mV), median frequency (Hz), and temperature (°C) of thigh. The FIR was worn for 82 ± 19 h before the experimental session, totaling 317 ± 74 kJ of energy irradiation. There was a significant increase (p < 0.05) for pre-MVC (318.5 ± 68.7 Nm) and post-MVC (284.1 ± 58.2 Nm), and a trend (p = 0.055) for significant increase for total work (4,122.2 ± 699.8 J) on FIR condition regardless of none change on temperature and electromyographic (EMG) signals. FIR improved the neuromuscular performance of knee extensors in resistance-trained males regardless of changes on temperature and EMG. The present results suggest that the FIR could optimize the neuromuscular performance with 82 ± 19 h of wear.

Use of a non-medicated plaster in chronic lumbar back pain: a randomized controlled trial

BACKGROUND

The latest technology on far infrared radiations reflects the radiations emitted by the human body and induces an antalgic and anti-inflammatory effect without active ingredients. Our primary aim was to assess pain level modifications throughout the treatment period with two different types of patches, compared to a placebo. As secondary aims, we focused on addressing patients' quality of life and range of motion changes with each patch.

METHODS

We assessed 54 patients with chronic lumbar back pain treated with FIT Therapy (far infrared technology) patch. Three different types of FIT Therapy patches (F4, F3, and placebo) were used according to the different power of action and patients allocated in a randomized fashion into the 3 arms of the study. Every single patient was assessed during the study using the VAS pain scale, the Roland Morris Disability Questionnaire for quality of life, and ROM for a total of 14 days.

RESULTS

Only the F4 patch group significantly reduced pain level at T14 compared to the placebo group (p<0.05). Meanwhile, F3 showed only a non-significant decrease compared to placebo (p=0.254). In terms of lifestyle improvements, both F3 and F4 recorded a decrease on the RMDQ of 4 and 6 points, respectively.

CONCLUSIONS

Currently, we still need further studies with longer follow-up to consider the FIT Therapy patches F4 a valid alternative as a "non-medicated pain relief", but it proved to have a role in alleviating painful symptoms and improving function in chronic lumbar back pain without adverse events.

Post-Match Recovery in Soccer with Far-Infrared Emitting Ceramic Material or Cold-Water Immersion

We investigated the effects of two common recovery methods; far-infrared emitting ceramic materials (Bioceramic) or cold-water immersion on muscular function and damage after a soccer match. Twenty-five university-level soccer players were randomized into Bioceramic (BIO; n = 8), Cold-water immersion (CWI; n = 9), or Control (CON; n = 8) groups. Heart rate [HR], rating of perceived exertion [RPE], and activity profile through Global Positioning Satellite Systems were measured during the match. Biochemical (thiobarbituric acid reactive species [TBARS], superoxide dismutase [SOD], creatine kinase [CK], lactate dehydrogenase [LDH]), neuromuscular (countermovement [CMJ] and squat jump [SJ], sprints [20-m]), and perceptual markers (delayed-onset muscle soreness [DOMS], and the perceived recovery scale [PRS]) were assessed at pre, post, 24 h, and 48 h post-match. One-way ANOVA was used to compare anthropometric and match performance data. A two-way ANOVA with post-hoc tests compared the timeline of recovery measures. No significant differences existed between groups for anthropometric or match load measures (P > 0.05). Significant post-match increases were observed in SOD, and decreases in TBARS in all groups (p < 0.05), without differences between conditions (p > 0.05). Significant increases in CK, LDH, quadriceps and hamstring DOMS (p < 0.05), as well as decreases in 20-m, SJ, CMJ, and PRS were observed post-match in all groups (p < 0.05), without significant differences between conditions (p > 0.05). Despite the expected post-match muscle damage and impaired performance, neither Bioceramic nor CWI interventions improved post-match recovery.

Germanium-Titanium-π Polymer Composites as Functional Textiles for Clinical Strategy to Evaluate Blood Circulation Improvement and Sexual Satisfaction

By continuously enhancing the blood flow, far-infrared (FIR) textile is anticipated to be a potential non-pharmacological therapy in patients with peripheral vascular disorders, for instance, patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) and experiencing vasculogenic erectile dysfunction (VED). Hence, we manufactured a novel polymer composite, namely, germanium-titanium-π (Ge-Ti-π) textile and aimed to evaluate its characteristics and quality. We also investigated the immediate and long-term effects of the textile on patients with ESRD undergoing HD and experiencing VED. The Ge-Ti-π textile was found to have 0.93 FIR emissivity, 3.05 g/d strength, and 18.98% elongation. The results also showed a 51.6% bacteria reduction and negative fungal growth. On application in patients receiving HD, the Ge-Ti-π textile significantly reduced the limb numbness/pain (p < 0.001) and pain score on the visual analog scale (p < 0.001). Moreover, the Doppler ultrasound assessment data indicated a significant enhancement of blood flow in the right hand after 1 week of Ge-Ti-π textile treatment (p < 0.041). In VED patients, the Ge-Ti-π underpants treatment significantly improved the quality of sexual function and increased the average penile blood flow velocity after 3 months of the treatment. Our study suggests that the Ge-Ti-π textile could be beneficial for patients with blood circulation disorders.

Utilisation of far infrared-emitting garments for optimising performance and recovery in sport: Real potential or new fad? A systematic review

BACKGROUND

Thanks to the specific materials they embed, far infrared (FIR)-emitting garments can interact with the body's physiological functions. Such effects have been sought in medicine and physiotherapy for a long time for the treatment/relief of a variety of pathologies and disabling conditions. Recently, FIR-emitting garments have been introduced in the sporting domain under the influence of manufacturers seeing here a new opportunity to support physical performance in athletes, though this is not clearly established. To fill this gap, in this systematic review, we summarize the scientific evidence on the use of FIR-emitting garments in sport and provide directions for future research by shedding light on current scientific limitations.

METHOD

Five scientific databases (PubMed, Cochrane, ScienceDirect, Scopus and SPORTDiscus) were searched by two independent reviewers. Studies investigating the effects of FIR-emitting garments on at least one physiological outcome related to exercise performance and/or recovery in humans were selected. The methodological quality of retained studies was assessed using the Physiotherapy Evidence Database (PEDro) scale.

RESULTS AND DISCUSSION

Eleven studies met the inclusion criteria and were included in the systematic review. Studies investigating similar outcomes related to exercise performance or recovery were scarce and results inconclusive, which prevents from drawing firm conclusion about the utilisation of FIR-emitting garments in athletes. However, these early results show that FIR-emitting garments may be of interest for exercise performance and recovery, mainly through their effects on the body's thermoregulation and haemodynamic function. The summary provided in this review can be used to inform the design of future studies. (PROSPERO registration number: CRD42021238029).

Effects of Far-Infrared Emitting Ceramic Materials on Recovery During 2-Week Preseason of Elite Futsal Players

Nunes, RFH, Cidral-Filho, FJ, Flores, LJF, Nakamura, FY, Rodriguez, HFM, Bobinski, F, De Sousa, A, Petronilho, F, Danielski, LG, Martins, MM, Martins, DF, and Guglielmo, LGA. Effects of far-infrared emitting ceramic materials on recovery during 2-week preseason of elite futsal players. J Strength Cond Res 34(1): 235-248, 2020-We investigated the effects of far-infrared emitting ceramic materials (cFIR) during overnight sleep on neuromuscular, biochemical and perceptual markers in futsal players. Twenty athletes performed a 2-week preseason training program and during sleep wore bioceramic (BIO; n = 10) or placebo pants (PL; n = 10). Performance (countermovement jump [CMJ]; squat jump [SJ]; sprints 5, 10, and 15-m) and biochemical markers (tumor necrosis factor alpha-TNF-α, interleukin 10-IL-10, thiobarbituric acid-reactive species [TBARS], carbonyl, superoxide dismutase [SOD], catalase [CAT]) were obtained at baseline and after the 1st and 2nd week of training. Delayed-onset muscle soreness (DOMS) and training strain were monitored throughout. Changes in ΔCMJ and ΔSJ were possibly (60/36/4 [week-1]) and likely (76/22/2 [week-2]) higher in BIO. Both groups were faster in 5-m sprint in week 2 compared with baseline (p = 0.015), furthermore, BIO was likely faster in 10-m sprint (3/25/72 [week 1]). Significant group × time interaction in %ΔTNF-α were observed (p = 0.024 [week-1]; p = 0.021 [week-2]) with values possibly (53/44/3 [week 1]) and likely (80/19/1 [week 2]) higher in BIO. The %ΔIL-10 decreased across weeks compared with baseline (p = 0.019 [week-1]; p = 0.026 [week-2]), showing values likely higher in BIO (81/16/3 [week-1]; 80/17/3 [week-2]). Significant weekly increases in %ΔTBARS (p = 0.001 [week-1]; p = 0.011 [week-2]) and %ΔCarbonyl (p = 0.002 [week-1]; p < 0.001 [week-2]) were observed compared with baseline, showing likely (91/5/4 [week-1]) and possibly (68/30/2 [week-2]) higher changes in BIO. Significant weekly decreases in %ΔSOD were observed compared with baseline (p = 0.046 [week 1]; p = 0.011 [week-2]), and between week 2 and week 1 (p = 0.021), in addition to significant decreases in %ΔCAT compared with baseline (p = 0.070 [week 1]; p = 0.012 [week 2]). Training strain (p = 0.021; very -likely [0/2/98]; week 1) and DOMS was lower in BIO (likely; 7 sessions) with differences over time (p = 0.001). The results suggest that the daily use of cFIR clothing could facilitate recovery, especially on perceptual markers during the early phases of an intensive training period.

Far-infrared Ray-mediated Antioxidant Potentials are Important for Attenuating Psychotoxic Disorders

Far-infrared ray (FIR) is an electromagnetic wave that produces various health benefits against pathophysiological conditions, such as diabetes mellitus, renocardiovascular disorders, stress, and depression etc. However, the therapeutic ap-plication on the FIR-mediated protective potentials remains to be further extended. To achieve better understanding on FIR-mediated therapeutic potentials, we summarized additional findings in the present study that exposure to FIR ameliorates stressful condition, memory impairments, drug dependence, and mitochondrial dysfunction in the central nervous system. In this review, we underlined that FIR requires modulations of janus kinase 2 / signal transducer and activator of transcription 3 (JAK2/STAT3), nuclear factor E2-related factor 2 (Nrf-2), muscarinic M1 acetylcholine receptor (M1 mAChR), dopamine D1 receptor, protein kinase C δ gene, and glutathione peroxidase-1 gene for exerting the protective potentials in response to neuropsychotoxic conditions

Antiedematous Effect Promoted by Occlusion of Legs with Compressive Socks Containing Infrared-Emitting Ceramic Particulates

Background: Published literature reports significant improvements in pathological conditions, such as pain, blood dyscrasias, and cellulite, after using topical occlusive accessories containing particulate ceramic materials. Objective: In this study, we investigated whether the use of a topical occluding garment made with synthetic fibers embedded with powdered ceramic materials could be beneficial to patients suffering from edema of lower limb extremities. Materials and methods: The cohort comprised 30 volunteers of both genders who were divided into two study groups. The bioceramic (BC) group wore compressive socks made of fabrics with embedded ceramic powder for 8 h a day for 28 days. The placebo group wore compressive socks of the same material without ceramic powder. The efficacy of the treatment was quantified through weekly plethysmographic measurements. In addition, pain relief was evaluated through a visual analog scale (VAS). Results: Data showed a statistically significant reduction in the edema volume for the BC group compared with the placebo group: 78.9 ± 10.7 mL versus 41.3 ± 5.6 mL, p = 0.003. Further, there was also greater pain relief for the BC group when compared with the placebo group, with a pain decrease of 7.0 ± 0.2 U versus 3.3 ± 0.2 U, respectively, on the VAS from 0 to 10 (p = 0.024). Conclusions: The topical occlusive therapy with compressive socks containing infrared-emitting ceramic particulate in its fabrics showed that they were more beneficial than the placebo garment in the treatment of edema of the inferior member extremities as well as in relief of associated pain.

Effects of Far-Infrared Emitting Ceramic Material Clothing on Recovery after Maximal Eccentric Exercise

The purpose of this study was to determine whether Far-Infrared Emitting Ceramic Materials worn as Bioceramic pants would improve neuromuscular performance, biochemical and perceptual markers in healthy individuals after maximal eccentric exercise. Twenty-two moderately active men were randomized into Bioceramic (n = 11) or Placebo (n = 11) groups. To induce muscle damage, three sets of 30 maximal isokinetic eccentric contractions of the quadriceps were performed at 60°·s^-1. Participants wore the bioceramic or placebo pants for 2 hours immediately following the protocol, and then again for 2 hours prior to each subsequent testing session at 24, 48 and 72 hours post. Plasma creatine kinase and lactate dehydrogenase activity, delayed-onset muscle soreness, perceived recovery status, and maximal voluntary contraction were measured pre-exercise and 2, 24, 48, and 72 hours post-exercise. Eccentric exercise induced muscle damage as evident in significant increases in delayed-onset muscle soreness at 24 - 72 hours (p < 0.05) and creatine kinase between Pre to 2, 24, 48 and 72 hours (p < 0.05). Despite the increased delayed-onset muscle soreness and creatine kinase values, no effect of Bioceramic was evident (p > 0.05). Furthermore, decreases in maximal voluntary contraction between Pre and immediately, 2, 24, 48 and 72 hours post (p < 0.05) were reported. However, the standardized difference was moderate lower for lactate dehydrogenase at 24 h (ES = 0.50), but higher at 48 h (ES = -0.58) in the Bioceramic compared to the Placebo group. Despite inducing muscle damage, the daily use of Far-Infrared Emitting Ceramic Materials clothing over 72 hours did not facilitate recovery after maximal eccentric exercise.

Effect of Shirts with 42% Celliant™ Fiber on tcPO2 Levels and Grip Strength in Healthy Subjects: A Placebo-controlled Clinical Trial

Celliant™ fabric contains quartz, silicon oxide and titanium oxide particles embedded into polymer fibers. Garments woven with Celliant™ yarns can be activated by body heat (conduction, convection and radiation) and remit the energy as far infrared radiation (FIR) back into the body. Wearing Celliant garments has been shown to increase blood flow and oxygen levels in the skin. In the present study we recruited twenty-four healthy volunteers (18-60 years of age) to wear a placebo shirt for 90 minutes, and after a 15-minute break, to wear a real Celliant shirt for 90 minutes. The mean transcutaneous oxygen (tcPO₂) measured over two sites (biceps and abdomen) was significantly increased at 3 time points (30, 60, and 90 minutes) by between 5-8% (P<0.05) in Celliant vs. placebo. The mean grip strength in the dominant hand measured at 90 minutes was 12.44% higher after wearing Celliant vs. after placebo (p=0.0002). There was a small but significant increase in systolic blood pressure (113.71 vs. 109.38; p=0.02) but no statistically significant changes in diastolic or mean blood pressure, heart rate, or skin temperature. These data provide more evidence of the physiological effects of FIR emitting garments and suggest they could be used for athletic training and recovery.

The Influence of Fiber Cross-Section on Fabric Far-Infrared Properties

Far-infrared radiation (FIR) possesses various promising properties that are beneficial to an individuals’ health. Exploring the interaction between fiber shapes and FIR performance is thought to be a significant means to develop highly-efficient FIR textile products. In this study, a non-additive triangular polyamide (PA) fiber showed excellent FIR properties in both theoretical simulation and experimental verification aspects. The triangular PA fiber affords a higher probability to facilitate large optical path difference, improving both FIR absorption and emission. Textiles woven with the specific triangular PA fiber achieved a remarkable emissivity of 91.85% and temperature difference of 2.11 Celsius, which is obviously superior to the reference circular fiber (86.72%, 1.52 Celsius). Considering the low cost, environmental stability, facile fabrication, as well as being environmentally friendly, this non-additive triangular PA fiber has great potential for high-performance and cost-effective FIR textiles in the future.

Randomized Controlled Trial Comparing the Effects of Far-Infrared Emitting Ceramic Fabric Shirts and Control Polyester Shirts on Transcutaneous PO2

Our aim was to confirm earlier studies showing tcPO₂ to be higher under clothing made with polyethylene terephalate (PET) fabric containing ceramic particles (CEL) compared to standard PET fabric. In previous studies PET garments were donned first to avoid possible persistent effects from ceramic particles. This study randomized donning sequence to avoid bias.

Biological effects and medical applications of infrared radiation

Infrared (IR) radiation is electromagnetic radiation with wavelengths between 760nm and 100,000nm. Low-level light therapy (LLLT) or photobiomodulation (PBM) therapy generally employs light at red and near-infrared wavelengths (600-100nm) to modulate biological activity. Many factors, conditions, and parameters influence the therapeutic effects of IR, including fluence, irradiance, treatment timing and repetition, pulsing, and wavelength. Increasing evidence suggests that IR can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment. Nerve cells respond particularly well to IR, which has been proposed for a range of neurostimulation and neuromodulation applications, and recent progress in neural stimulation and regeneration are discussed in this review. The applications of IR therapy have moved on rapidly in recent years. For example, IR therapy has been developed that does not actually require an external power source, such as IR-emitting materials, and garments that can be powered by body heat alone. Another area of interest is the possible involvement of solar IR radiation in photoaging or photorejuvenation as opposites sides of the coin, and whether sunscreens should protect against solar IR? A better understanding of new developments and biological implications of IR could help us to improve therapeutic effectiveness or develop new methods of PBM using IR wavelengths.