Association of COMT gene variability with pain intensity in patients after total hip replacement.

Pain is one of the most interdisciplinary clinical symptoms of a disease. The aim of the study was to evaluate the association of COMT gene polymorphism with pain perception in patients after total hip replacement (THR). The study included 195 patients qualified for surgical treatment (THR) due to osteoarthritis. Patients previously undergoing hip replacement subsequently underwent multimodal pain management therapy, in accordance with the recommendations for treating postoperative pain. The intensity of pain was measured three times at pre-defined time intervals: 1.5, 6 and 12 months after hip replacement, using the visual analogue scale. Single nucleotide polymorphism (SNP) in the COMT gene rs4680: A>G (Val158Met), rs6269: A>G (promoter region), rs4633: C>T (His62His) and rs4818: C>G (Leu136Leu) was genotyped. COMT SNP frequency distribution was analysed. For rs6269 and rs4818, the minor allele was the G allele (38.7 and 38.5%, respectively). It was also observed that rs4633 (T) allele frequency (50%) equalled that of the rs4680 (A) allele (50%). We assessed COMT haplotype frequency in the patients studied. The most frequent haplotype was haplotype M (ATCA) (50%), the rarest haplotype was haplotype R (ATGG), with a frequency of 0.3%. The most frequent diplotype was H/M, which was found in 37.95% of the patients. The frequency of other diplotypes was: M/M-24.10%, H/H-15.90% and L/M-13.33%. The study showed a significant association of rs4818 G allele and equivalent COMT H haplotype with lower sensitivity to pain after hip replacement.

The VEGFA gene and anterior cruciate ligament rupture risk in the Caucasian population.

The aim of the present study was to analyse VEGFA rs699947, rs1570360, and rs2010963 polymorphisms with susceptibility to anterior cruciate ligament rupture (ACLR) in a Polish population. The study included 412 physically active Caucasian participants. The study group consisted of 222 individuals with surgically diagnosed primary ACLR qualified for ligament reconstruction (ACLR group). The control group consisted of 190 apparently healthy participants without any history of ACLR (CON group). Three polymorphisms within the VEGFA (rs699947, rs1570360, and rs2010963) gene were chosen for investigation due to their significance in the angiogenesis signalling pathway and previous associations with risk of ACLRs. Both single-locus and haplotype-based analyses were conducted. No significant differences in the allele and genotype frequency distributions were noted for the rs699947 and rs1570360 polymorphisms. In contrast, rs2010963 was associated with risk of ACLR in the codominant (p=0.047) and recessive model (p=0.017). In the latter, the CC genotype was overrepresented among individuals with ACL rupture (23.4% vs 14.2%, OR=1.85 [1.11-3.08]). Two VEGFA haplotypes were associated with ACLR under the additive (global score=11.39, p=0.022) and dominant model (global score=11.61, p=0.020). The [C;G;G] haplotype was underrepresented in the ACLR group (52.2% vs. 60.3%), whereas the [C;G;C] haplotype was overrepresented (2.9% vs 0.5%). The results obtained suggest a potential correlation between the VEGFA rs2010963 polymorphism and ACLR risk, suggesting that harbouring this specific C allele may be an unfavourable risk factor for a knee injury in Caucasian participants from Poland.

ADIPOQ polymorphisms are associated with changes in obesity-related traits in response to aerobic training programme in women.

Among genetic variants of the ADIPOQ gene +276 G>T (rs1501299) and -11377 G>C (rs266729) are the most frequently investigated polymorphisms which were described in the context of genetic conditioning for a predisposition to obesity. However, the information of polymorphisms' potential modifying effect on obesity-related traits achieved through training procedures are still unknown. DNA was extracted from buccal cells donated by the 201 participants and genotyping was carried out using real-time PCR. The genotype distribution was examined in a group of women measured for chosen traits before and after the completion of a 12-week training programme. Our results suggest that the ADIPOQ genotypes analyzed individually or in combination can modulate training-induced body mass measurements changes: after the training programme, carriers of rs1501299 T allele and rs266729 C allele were characterized by a greater reduction in fat mass percentage (FM), fat mass, and body mass. Moreover, the ADIPOQ polymorphisms were associated with changes in lipid profile in response to training. Additionally, we showed three main effects of genotypes for the FM, LDL-C (rs266729), and TBW (rs1501299). Our study indicate that the both polymorphisms are associated with changes in obesity-related traits in response to 12-week aerobic training programme in Caucasian women. From this evidence, it could be concluded that rs1501299 G and rs266728 G variants may be considered as disadvantageous factor in the context of training-induced effects on body mass traits.

AGTR2 and sprint/power performance: a case-control replication study for rs11091046 polymorphism in two ethnicities.

We aimed to replicate, in a specific athletic event cohort (only track and field) and in two different ethnicities (Japanese and East European, i.e. Russian and Polish), original findings showing the association of the angiotensin-II receptor type-2 gene (AGTR2) rs11091046 A>C polymorphism with athlete status. We compared genotypic frequencies of the AGTR2 rs11091046 polymorphism among 282 track and field sprint/power athletes (200 men and 82 women), including several national record holders and Olympic medallists (214 Japanese, 68 Russian and Polish), and 2024 control subjects (842 men and 1182 women) (804 Japanese, 1220 Russian and Polish). In men, a meta-analysis from the two combined cohorts showed a significantly higher frequency of the C allele in athletes than in controls (odds ratio: 1.62, P=0.008, heterogeneity index I 2 =0%). With regard to respective cohorts, C allele frequency was higher in Japanese male athletes than in controls (67.7% vs. 55.9%, P=0.022), but not in Russian/Polish male athletes (61.9% vs. 51.0%, P=0.172). In women, no significant results were obtained by meta-analysis for the two cohorts combination (P=0.850). The AC genotype frequency was significantly higher in Russian/Polish women athletes than in controls (69.2% vs. 42.1%, P=0.022), but not in Japanese women athletes (P=0.226). Our results, in contrast to previous findings, suggested by meta-analysis that the C allele of the AGTR2 rs11091046 polymorphism is associated with sprint/power track and field athlete status in men, but not in women.

GSTP1 c.313A>G polymorphism in Russian and Polish athletes.

The GSTP1 gene encodes glutathione S-transferase P1, which is a member of the glutathione S-transferases (GSTs), a family of enzymes playing an important role in detoxification and in the antioxidant defense system. There is some evidence indicating that GSTP1 c.313A>G polymorphism may be beneficial for exercise performance. Therefore, we decided to verify the association between the frequency of GSTP1 c.313A>G variants, physical performance, and athletes' status in two cohorts: in a group of Russian athletes (n = 507) and in an independent population of Polish athletes (n = 510) in a replication study. The initial association study conducted with the Russian athletes revealed that the frequency of the minor G allele was significantly higher in all athletes than in controls; that was confirmed in the replication study of Polish athletes. In the combined cohort, the differences between athletes (n = 1017) and controls (n = 1246) were even more pronounced (32.7 vs 25.0%, P < 0.0001). Our findings emphasize that the G allele of the GSTP1 gene c.313A>G single nucleotide polymorphism is associated with improved endurance performance. These observations could support the hypothesis that the GSTP1 G allele may improve exercise performance by better elimination of exercise-induced ROS.

Pain perception and cardiovascular system response among athletes playing contact sports.

The aim of this study was to determine whether the contact sports change the perception of pain as assessed by the cold pressor test (CPT), and if the test induces the same reaction of the cardiovascular system in contact athletes and non-athletes. The study involved 321 healthy men; 140 contact athletes and 181 students of the University of Szczecin (control). Pain threshold and pain tolerance were evaluated using CPT. Cardiovascular measurements were made during CPT. The contact athletes showed a much higher tolerance to pain than the control group (median time 120 vs. 94 s, respectively, p = 0.0002). The thresholds of pain in both groups did not differ significantly between the groups. Systolic blood pressure measured before and during the test in all three measurements was statistically significantly higher in athletes compared with the control group. Heart rate and diastolic blood pressure did not differ significantly between the studied groups.

Effect of interleukin 6 -174G>C gene polymorphism on opioid requirements after total hip replacement.

OBJECTIVE: In recent years, increasing attention has been paid to the contribution of genetic factors to variability in patient pain threshold and the efficacy of pain management. One of the genes implicated in pain pathology and treatment response is interleukin 6 (IL6). The aim of the present study was to evaluate the association between IL6 (rs1800795: -174G>C) and opioid requirements in patients after total hip replacement (THR). METHODS: A total of 196 patients eligible for the study (126 women, 70 men) were subjected to THR. The THR procedure was performed using spinal anaesthesia after implementing routine peri-operative monitoring. After the procedure each patient was individually observed, and the patient-specific chart of dynamic changes in pain perception was recorded, using the five-level Verbal Rating Scale (VRS). The multimodal analgesic treatment after THR was defined by the operating surgeons after considering indications and contraindications to the use of different groups of drugs (opioid and non-opioid analgesics). Postoperative pain was controlled by the patient-controlled analgesia method and VRS during the day-time, as well as night-time nurse-controlled analgesia. All medication adjustments were recorded in the individual patient files. In the case of moderate pain intensity (VRS-assessed), a patient was administered the non-opioid analgesic drug, and for high intensity pain the opioid. The analysis of pain relief therapy included information on the drugs applied, mode of dosing (single or multiple), daily dose, route of administration, and drug refusal due to the absence of pain recorded each study day, i.e. on the day of surgery and recovery in the postoperative room (day 0), and then daily from day 1 to day 6. Polymorphism rs1800795:G>C in the promoter region of the IL6 gene (-174G>C) was determined using the PCR-RFLP method. RESULTS: The patients carrying at least one IL6 -174G allele (GG homozygote and GC heterozygote) were administered opioids significantly more often on days 0 (p = 0.0029), 3 (p = 0.019) and 4 (p = 0.031) after surgery compared with CC homozygous patients. Those patients also required a significantly higher opioid dose on days 3 (p = 0.029) and 4 (p = 0.030). Multivariate analysis demonstrated that the presence of the -174G allele was an independent factor predisposing patients to the administration of opioids during the first 24 h [p = 0.001, odds ratio (OR) 7.1, 95 % confidence interval (CI) 2.17-22.7], on day 3 (p = 0.01, OR 2.79, 95 % CI 1.25-6.26) and day 4 (p = 0.01, OR = 2.61, 95 % CI 1.17-5.79). CONCLUSION: The presence of the G allele IL6 gene (-174G>C) polymorphism was found to be an independent factor predisposing to a higher dose and more frequent administration of opioids in the first days after total hip replacement.

The Impact of Resistance Training on Equilibrium Abilities and Quality of Life in Older Adults after SARS-CoV-2 Survival.

Background: The scientific literature on COVID-19 and its long-term impacts on all-body systems and their treatments is still limited. The aim of the study was to create a safe protocol-based intervention to improve functional and equilibrium abilities in older adults impacted by COVID-19. Methods: This study used a sample of 46 people (intervention group: n = 26; control group: n = 20). Resistance training (RT) was held twice a week, with 60 min per session for 8 weeks. The postural stability and quality of life questionnaire (WHQOOL) was completed during pre- and post-testing. Results: The results indicated significant differences in overall stability index (OSI) with eyes open (EO), anterior-posterior stability index (APSI) EO, fall-risk index 6-2 (FRI6-2) values in males (p < 0.05), and APSI EO (p < 0.05) values in females compared to control groups, respectively. In the training, a significant improvement was reported in OSI EO and APSI EO (p < 0.05) female groups compared to baseline results and in FRI6-2 values in both gender groups (p < 0.01-men, p < 0.05-women). The effect of the intervention was recorded in the intervention group in the OSI EO (Z = -3.12, p < 0.01, R = 0.533) and FRI6-2 (Z = -2.06, p < 0.05, R = 0.354). Additionally, significantly different reactions between the groups were observed in the psychological domain (DOM2) (Z = 2.194, p < 0.028, R = 0.389), social relationship domain (DOM3) (Z = 2.051, p < 0.0403, R = 0.361), and in question 2 concerning general health (Z = 3.309, p < 0.0009, R = 0.535). Conclusions: The findings indicate that RT had a positive effect on older adults affected by COVID-19, led to a significant improvement in their postural stability, and had a significant impact on elements of psychological well-being and quality of life.

Individual Factors Modifying Postoperative Pain Management in Elective Total Hip and Total Knee Replacement Surgery.

Total hip and knee replacements are the most common orthopedic procedures performed due to osteoarthritis. Pain is an intrinsic symptom accompanying osteoarthritis, persisting long before surgery, and continuing during the preoperative and postoperative periods. Appropriate pain management after surgery determines the comfort, duration, and cost of hospitalization, as well as the effectiveness of postoperative rehabilitation. Individual differences in pain perception and tolerance in orthopedic patients remain an important research topic. Therefore, the aim of this study was to investigate the predictors of analgesic requirements (morphine, acetaminophen, and ketoprofen), including individual pain threshold and tolerance, body mass index (BMI), diabetes, and beliefs about pain control in patients undergoing elective hip or knee arthroplasty using a multilevel regression model (N = 147, 85 women, 62 men, 107 after hip replacement, and 40 after knee replacement). Results: Higher pain tolerance was associated with a lower dose of morphine per kg after surgery. Patients undergoing hip surgery received a lower dose of ketoprofen than patients undergoing knee surgery. The more the patient believed in personal pain control, the stronger the negative relationship between pain tolerance and morphine requirement. The lowest doses were given to patients with the highest pain tolerance and the greatest belief in personal control. Factors such as belief in pain control and pain tolerance should be considered in comprehensive postoperative pain management in orthopedic patients to reduce opioid doses and, thus, side effects.

SCN9A rs6746030 Polymorphism and Pain Perception in Combat Athletes and Non-Athletes.

One of the genes associated with pain perception is SCN9A, which encodes an α-subunit of the voltage gated sodium channel, NaV1.7, a crucial player in peripheral pain sensation. It has been suggested that a common missense polymorphism within SCN9A (rs6746030; G>A; R1150W) may affect nociception in the general population, but its effects of pain perception in athletes remain unknown. Therefore, the aim of the study was to investigate the association between a polymorphism within SCN9A (rs6746030) and pain perception (pain threshold and pain tolerance) in the group of combat athletes (n = 214) and students (n = 92) who did not participate in sports at a professional level. Genotyping was carried out using TaqMan Real-Time PCR method. No significant differences were found between the SCN9A genotype distributions with respect to the pain threshold. However, the probability of having a high pain threshold was higher in the combat sports group than in the control group. The probability of having a decreased pain tolerance was higher in the carriers of the GA and AA genotype than in the homozygotes of the GG genotype. Moreover, the possibility of having a high pain threshold was higher in the combat athlete group than in the control group. The results of our study suggest that the SCN9A rs6746030 polymorphism may affect pain perception. However, the additional effect of the experimental group may suggest that pain tolerance is significantly modulated by other factors, such as the systematic exposure of the athletes' bodies to short-term high-intensity stimuli during training sessions.

Changes in pain perception during pregnancy after one-time maximal physical exertion and an 8-week high-intensity interval training.

Background: Pain, a subjective sensation, poses a great challenge to the human body as a stressor. There is empirical evidence that moderate to intense physical activity increases pain tolerance and this may be critical during pregnancy for optimal pregnancy, fetal development, and delivery. To the best of our knowledge, it is the first study examining the changes in pain perception in pregnant women after a maximal progressive exercise test and after 8 weeks of high-intensity interval training (HIIT). Methods: Thirty-five women with uncomplicated singleton pregnancies between 13 and 28 weeks of gestation participated in the study. The HIIT intervention was developed in accordance with the recommendations and available data on HIIT during pregnancy. The maximal progressive cardiopulmonary exercise test was performed on a cycle ergometer with an electronically controlled load. Pressure pain threshold and pressure pain tolerance were measured with an algometer. Results: We found significant effects of the maximal exercise test and high-intensity interval training, such that the pregnant women had higher pain tolerance after the maximal exercise test than before and after the high-intensity interval training than the baseline. Conclusion: Our results suggest that post-exercise analgesia may be important in pregnant women and that high-intensity interval training appears to be beneficial for pregnant women to improve their pain tolerance while being obstetrically safe. Increased pain tolerance before labor could lead to better management of pain during labor and in the postpartum and lactation periods. Increasing pregnant women's awareness of this issue can improve their wellbeing and provide more comfort during labor.

Level of Disability after Total Hip Replacement in Patients with Some COMT Gene Polymorphism.

BACKGROUND: The COMT gene encodes the enzyme catechol-O-methyltransferase, which is a key modulator of dopaminergic and adrenergic neurotransmission. Hip osteoarthritis is accompanied by reduced mobility and some level of disability. In our study, we analyzed the association between some COMT gene polymorphisms and reduced mobility in patients after total hip replacement (THR). METHODS: The operative procedures were performed on 195 patients with symptomatic and radiologically advanced hip osteoarthritis. In the postoperative follow-up, we assessed hip function with the Harris Hip Score (HHS) and the degree of disability with the Oswestry Disability Index (ODI). These procedures were repeated three times at defined intervals (one week, six weeks, and six months) after the total hip replacement. Genomic DNA was extracted from peripheral blood. SNPs in the COMT genes rs4680:A>G, rs6269:A>G, rs4633:C>T, and rs4818:C>G were genotyped. RESULTS: Our findings suggest an association between COMT gene variability and the level of disability measured by the Oswestry Disability Index (ODI) in patients after total hip replacement (THR). CONCLUSIONS: A higher number of COMT G alleles (rs4818) is an independent factor in a significant reduction in disability degree at both one week and six months after total hip replacement (THR), regardless of age or gender.

The Influence of the Differentiation of Genes Encoding Peroxisome Proliferator-Activated Receptors and Their Coactivators on Nutrient and Energy Metabolism.

Genetic components may play an important role in the regulation of nutrient and energy metabolism. In the presence of specific genetic variants, metabolic dysregulation may occur, especially in relation to the processes of digestion, assimilation, and the physiological utilization of nutrients supplied to the body, as well as the regulation of various metabolic pathways and the balance of metabolic changes, which may consequently affect the effectiveness of applied reduction diets and weight loss after training. There are many well-documented studies showing that the presence of certain polymorphic variants in some genes can be associated with specific changes in nutrient and energy metabolism, and consequently, with more or less desirable effects of applied caloric reduction and/or exercise intervention. This systematic review focused on the role of genes encoding peroxisome proliferator-activated receptors (PPARs) and their coactivators in nutrient and energy metabolism. The literature review prepared showed that there is a link between the presence of specific alleles described at different polymorphic points in PPAR genes and various human body characteristics that are crucial for the efficacy of nutritional and/or exercise interventions. Genetic analysis can be a valuable element that complements the work of a dietitian or trainer, allowing for the planning of a personalized diet or training that makes the best use of the innate metabolic characteristics of the person who is the subject of their interventions.

The Use of Thermography as an Auxiliary Method for Monitoring Convalescence after Facelift Surgery: A Case Study.

Although IR thermography is widely used in medical diagnostics, there are no reports that describe the use of IR thermography in the evaluation of post-plastic-surgery regeneration processes. The aim of the study was to evaluate the potential of thermography as a method which, among others, allows us to determine the location and extent of the inflammatory process, supporting the clinical evaluation of the patient's convalescence after a facelift surgery using the SMAS technique. During the study and in order to monitor the convalescence process, the patient had a series of face thermograms performed before surgery and up to the 6th week after it. The healing process after surgery was multidirectional for the contralateral areas of the face, leading to thermal asymmetry lasting up to the 3rd week of convalescence. The lowest Tmean values for ROIs were recorded in week 3 of the study and then they gradually increased, in week 6 after surgery, to the following values: chin = 33.1 ± 0.72 °C; cheek left = 33.0 ± 0.26 °C; cheek right = 33.2 ± 0.51 °C; ZFL = 33.8 ± 0.45 °C; ZFR = 33.6 ± 0.74 °C; ZLL = 32.6 ±0.55 °C; ZLR = 32.3 ± 0.32 °C. The temperatures of these areas were still lower than the baseline values obtained before surgery by 0.5-1.4 °C. The usefulness of thermography in the evaluation of post-operative convalescence in facial plastic surgery procedures shows potential in the context of diagnostic assessment of the dynamics of changes in the healing process.

Lack of Association between (AAT)n Polymorphism of the CNR1 Gene Encoding the Cannabinoid Receptor (CB1) and Patient's Quality of Life.

Genetic factors may predispose persons to decreased pain excitability. One of the interesting modulators affecting pain perception may be polymorphisms of the cannabinoid receptor type 1 (CNR1) gene. In this study, we examined the association between three-nucleotide repeats (AAT) polymorphism located in the 3'UTR non-translational region of CNR1 and the patient's quality of life after total hip arthroplasty. Our study examined the degree of pain sensation, hip function, and the patient's performance at defined intervals after elective hip replacement due to degenerative changes. The study included 198 patients (128 women and 70 men). The average age was 67 years. PCR genotyping assay was used to identify the (AAT)n triplet repeat polymorphism in the CNR1 gene. The (AAT)n repeat number was determined by sequencing using a standard sequencing protocol. Our study found no statistically significant association between the degree of pain, hip function, and the change in the degree of disability and the (AAT)n polymorphism in the CNR1 gene, no statistically significant correlations between clinical symptoms, the patient's age, and the number of AAT repeats, no association between the length of the allele and the degree of pain, hip function, and the change in disability.

Is Physical Activity an Effective Factor for Modulating Pressure Pain Threshold and Pain Tolerance after Cardiovascular Incidents?

The purpose of this study was to investigate whether regular physical activity can alter the pressure pain threshold, pain tolerance, and subjective pain perception in individuals who have experienced a cardiovascular event. The study involved 85 individuals aged 37 to 84 years (M = 65.36) who qualified for outpatient cardiac rehabilitation, which consisted of 24 physical training sessions. The patients were all tested twice: on the first and last day of the outpatient cardiac rehabilitation program. Assessments of the pressure pain threshold and pain tolerance were performed with an algometer. To assess the pain coping strategies, the Pain Coping Strategies Questionnaire (CSQ) and parenting styles were measured retrospectively with subjective survey questions. The main results of the study showed that patients achieved significantly higher pressure pain thresholds after a physical training cycle (ps < 0.05, η2 = 0.05-0.14), but found no differences in the pain tolerance (ps > 0.05). A lower preference for the better pain coping strategy explanation (ß = -0.42, p = 0.013) and growing up in a family with a less neglectful atmosphere (ß = -0.35, p = 0.008) were associated with increased pressure pain threshold after physical training. The results suggest that physical activity is an important factor in modulating the pressure pain threshold.

No Association between Genetic Variants of the COMT and OPRM1 Genes and Pain Perception among Patients Undergoing Total Hip or Knee Arthroplasty for Primary Osteoarthritis.

Each year approximately 1 million total hip replacements are performed worldwide. The most common indications to choose this procedure are rest pain and pain after activity as well as functional limitations influencing daily activities. Experimental pain is highly variable by individuals, which is partly due to genetics. The aim of the study was to investigate a possible association of the catechol-O-methyltransferase (COMT) and µ-opioid receptor (OPRM1) genotypes with pain perception in patients undergoing total hip replacement and total knee replacement taking into account aspects such as age, sex and diabetes. The study included 207 patients (119 females, 88 males, median age 65 years, range 33−77) that qualified for surgical treatment (total hip replacement and knee arthroplasty) due to osteoarthritis. Pain sensitivity measurement was performed using a standard algometer. The genomic DNA was extracted from the buccal cells.. Single locus analysis was conducted using a general linear model. In the study group, we did not find statistically significant genetic associations between variants of COMT and OPRM1 and pain thresholds/pain tolerance. The analysis of subjective pain perception using the visual analog scale did not show any relationship between the OPRM1 rs1799971A>G variant and COMT rs4680, rs4633, rs4818 and rs6269.

Individual Characteristics and Pain Sensitivity during Pregnancy-A Cross-Sectional Study in Pregnant and Non-Pregnant Women.

The aim of the study was to describe the characteristics and factors related to pain perception in pregnant women, such as optimism, personality traits, and fear of developing COVID-19 consequences. Sixty-six pregnant women aged 23 to 42 years participated in the study, and the comparison group consisted of n = 59 non-pregnant female students aged 19 to 23 years. Pressure pain threshold and pain tolerance were measured with an algometer. To assess psychological characteristics, the Life-Orientation Test-Revised was used to assess optimism, the Fear of COVID-19 Scale was used to assess COVID-19 anxiety, and the Ten-Item Personality Inventory was applied to assess personality traits in a five-factor model. The main results of the study showed that pain tolerance was significantly lower in both dominant and non-dominant hand pregnant women than in the comparison group. The studied pregnant women had higher scores for conscientiousness, fear of COVID-19, and optimism compared with the non-pregnant women. Regression analysis showed that the variability in pain perception among pregnant women could not be explained by individual differences in personality traits, optimism, and fear of COVID-19.

Effects of Acute Caffeine Intake on Power Output and Movement Velocity During a Multiple-Set Bench Press Exercise Among Mild Caffeine Users.

The main goal of this study was to evaluate the effectiveness of an acute dose of caffeine (6 mg/kg body mass (b.m.)) on power output and bar velocity during a bench press multiple-set resistance training session in participants with mild daily caffeine consumption (in the range of 1 to 3 mg/kg/b.m). Thirteen recreationally active male participants (age: 21.9 ± 1.2 years, body mass: 74.4 ± 5.3 kg, body mass index: 23.1 ± 1.6 kg/m2, bench press onerepetition maximum (1RM): 79.2 ± 14.9 kg), with daily caffeine ingestion of 1.56 ± 0.56 mg/kg/b.m., participated in the study with a randomized double-blind experimental design. Each participant performed two identical experimental sessions, 60 min after the intake of a placebo (PLAC) or 6 mg/kg/b.m. of caffeine (CAF-6). In each experimental session, participants performed 5 sets of 5 repetitions of the bench press exercise with a load equivalent to 70% 1RM. The eccentric and concentric phases of the bench press exercise were performed at maximal possible velocity in each repetition. Bar velocity was recorded with a linear position transducer and power output was calculated using velocity and load data. A two-way repeated measures ANOVA indicated no significant substance x set interaction for mean power output (MP), mean bar velocity (MV), peak power output (PP) and peak bar velocity (PV). However, there was a significant main effect of substance on MP (p < 0.01; η2 = 0.47) and MV (p < 0.01; η2 =0.45). Post hoc analysis for main effect revealed that MP and MV values in the CAF-6 group were higher than in the PLAC group in all 5 sets of the exercise (p < 0.05). In conclusion, this study demonstrated that an acute dose of caffeine before resistance exercise increased mean power output and mean bar velocity during a multiple-set bench press exercise protocol among mild caffeine users.

Association between Polymorphism rs1799732 of DRD2 Dopamine Receptor Gene and Personality Traits among MMA Athletes.

Four factors-namely, harm avoidance, novelty seeking, reward addiction and persistence-represent the nature of temperament that is not genetically determined in itself. It was shown in earlier studies that a strong propensity to look for novelty or a tendency to engage in risky behavior is correlated with genetic variants in the area of the genes encoding dopamine receptors. Therefore, the aim of this study is to determine whether there is a relationship between personality traits and genetic variants in the area of the DRD2 dopamine receptor gene in MMA athletes. The participants consisted of 85 mixed martial arts (MMA) athletes and 284 healthy, non-MMA male participants. Their personality traits were measured using the Revised Temperament and Character Inventory. Blood was collected for genetic assays and all samples were genotyped using the real-time PCR method. We observed a statistically significant effect of a complex factor of the DRD2 rs1799732 genotype on MMA participants' control and reward dependence. Engaging in high-risk sport may be associated with several personality characteristics. The DRD2 rs1799732 polymorphism may be associated with reduced harm avoidance in martial arts athletes, thereby modulating athletes' predisposition to participate in high-risk sport.