Changes in hamstring contractile properties during the competitive season in young football players.

Background: The study aimed to examine alterations and imbalances in hamstring muscle contractile properties among young football players throughout their competitive season, and to understand how these changes might contribute to the risk of muscle injuries. Hamstring injuries are particularly common in football, yet the underlying causes and effective prevention methods remain unclear. Methods: The research involved 74 young footballers who were assessed before the season (pre-test) and after 12 weeks of training (post-test). To evaluate changes in hamstring muscle contractile properties, specifically the left and right biceps femoris (BF) and semitendinosus (ST), tensiomyography (TMG) parameters were utilized. Results: In comparison to the BF muscle, significant differences in time delay (Td) between the left and right sides in the post-test (p = 0.0193), and maximal displacement (Dm) between the left and right sides at the pre-test (p = 0.0395). However, significant differences in Dm were observed only in the left ST muscle between the pre- and post-tests (p = 0.0081). Regarding lateral symmetry, BF registered measurements of 79.7 ± 13.43 (pre-test) and 77.4 ± 14.82 (post-test), whereas ST showed measurements of 87.0 ± 9.79 (pre-test) and 87.5 ± 9.60 (post-test). Conclusions: These assessments provided TMG reference data for hamstring muscles in young footballers, both before the season and after 12 weeks of in-season training. The observed changes in the contractile properties and decrease in lateral symmetry of the BF in both tests suggest an increased risk of injury.

Muscle contraction time after caffeine intake is faster after 30 minutes than after 60 minutes.

BACKGROUND: This study aimed to determine the optimal time point, either 30 or 60 minutes, at which muscle reactivity to caffeine administration is highest. Unlike previous studies that focused on the nervous system response, we employed tensiomyography (TMG) to directly assess the effects of caffeine on muscle fibers. METHODS: TMG measurements were performed on the gastrocnemius medialis muscle of 42 male athletes who regularly consumed caffeine. Participants received a dose of 6 mg/kg body weight and TMG measurements were taken prior to caffeine intake, as well as 30 and 60 minutes afterward. RESULTS: Analysis of TMG parameters including time to contraction (Tc), time delay (Td), and maximal displacement (Dm) revealed that muscles exhibited faster contractions and greater stiffness at the 30-minute mark compared to both pre-caffeine intake and the 60-minute time point. Time exerted a significant main effect on Tc (F(2, 246) = 12.09, p < .001, ή2p = 0.09), Td (F(2, 246) = 3.39, p = .035, ή2p = 0.03), and Dm (F(2, 246) = 6.83, p = .001, ή2p = 0.05), while no significant effect of body side was observed. CONCLUSIONS: The findings indicate that muscle contraction time (Tc) and delay time (Td) are influenced by the time elapsed since caffeine ingestion, with the fastest responses occurring after 30 minutes. Additionally, a systemic effect of caffeine was observed, as there were no discernible differences in measurements between the two sides of the body. TMG proves to be an effective noninvasive method for assessing muscle responses following caffeine administration.

Comparison of concentric and eccentric resistance training in terms of changes in the muscle contractile properties.

The habitual use of resistance exercises involving concentric and eccentric contractions can increase muscle strength, speed and endurance. However, current knowledge has limited potential to fully understand the application of such resistance training and the muscle changes that occur to differentiate these two types of training. The aim of this study was to compare the effects of concentric contraction (CON) and eccentric contraction (ECC) during an acute bout of resistance training on the hamstring contractile properties. A group of 20 female recreational athletes were divided into two equal groups, CON training and ECC training. The contractile properties of the muscles on both sides of the body were assessed using tensiomyography (TMG): biceps femoris (BF) and semitendinosus (ST). The muscles were assessed twice, before and after 10 maximal repetitions of either concentric or eccentric isotonic contractions. The results indicate a greater change in TMG parameters with ECC training, with p < 0.001 (Td and Tc). An acute bout of resistance training induces changes in the muscle hamstrings contractile properties in both CON and ECC training. Eccentric training causes greater changes than concentric training, shortening contraction time (Td, Tc), increase radial displacement velocity (Vrd) and affecting changes in muscle belly displacement (Dm), so may be more effective in training.

A Potential Objective Sign of Central Sensitization: Referred Pain Elicited by Manual Gluteus Minimus Muscle Exploration is Coincident with Pathological Autonomic Response Provoked by Noxious Stimulation.

Referred pain/sensation provoked by trigger points suits the nociplastic pain criteria. There is a debate over whether trigger points are related to a peripheral phenomenon or central sensitization (CS) processes. Referred pain is considered a possible sign of CS, which occurs probably mainly due to the abnormal activity of the immune and autonomic nervous systems. To confirm abnormal autonomic reactivity within the referred pain zone of active trigger points, a new diagnostic tool, the Skorupska Protocol® (the SP test®), was applied. The test uses noxious stimulation (10 minutes of dry needling under infrared camera control) as a diagnostic tool to confirm abnormal autonomic nervous system activity. A response to the SP test® of healthy subjects with referred pain sensations provoked by latent trigger points (LTrPs) stimulation was not explored before. The study aims at examining if LTrPs can develop an autonomic response. Methods. Two groups of healthy subjects, (i) gluteus minimus LTrPs with referred pain (n = 20) and (ii) control (n = 27), were examined using the SP test®. Results. Abnormal autonomic activity within the referred pain zone was confirmed for all analyzed LTrPs subjects. 70% of control subjects had no feature of vasodilatation and others presented minor vasomotor fluctuations. The size of vasomotor reactivity within the referred pain zone was LTrPs 11.1 + 10.96% vs. control 0.8 + 0.6% (p < 0.05). Conclusions. Noxious stimulation of latent TrPs induces abnormal autonomic nervous system activity within the referred pain zone. The observed phenomenon supports the concept of central nervous system involvement in the referred pain patomechanizm.

Comparison of the effects of six-week time-restricted eating on weight loss, body composition, and visceral fat in overweight older men and women.

The aim of this study was to determine the effectiveness of a six-week time-restricted eating (TRE) intervention in reducing body weight, fat loss, and visceral fat in overweight, older adult men and women (age range = 65-74 years). Another objective was to determine the feasibility of widespread use of TRE in older women and men. The study randomly assigned 116 healthy, non-smoking participants to one of two conditions: TRE or educational control participants. Participants in the TRE group were instructed to not consume calorie containing beverages or food for 16 h per day, from 8:00 pm to 12:00 pm. Participants in the control group were instructed to follow a meal plan based on their previous habits. The changes in body weight and body composition were determined using a SECA mBCA 515 analyzer. The six-week TRE intervention resulted in a significant decrease in body weight in both men and women (-1.8 kg and-1.3 kg, respectively; p = 0.03). In men, a significant decrease in visceral fat mass (-0.54 l; p ≤ 0.001) and waist circumference (-2.9 cm; p ≤ 0.015) was observed. No significant changes in either visceral fat or waist circumference were observed in women. Additionally, no change in skeletal muscle mass was observed in either the control or TRE group. More than 99 % of female and 98 % of male participants were able to adhere to the prescribed time-restricted eating (16/8) plan, suggesting that this dietary approach could have beneficial effects on the body composition of overweight older men and may also reduce body weight in overweight, older women.

Glial-Plug Proliferation after Inverted Internal Limiting Membrane Flap Technique for Idiopathic Macular Hole.

Purpose: This study aimed to analyze the effect of multiple folded internal limiting membrane (ILM) flap in the inverted ILM flap technique on postoperative outcomes of patients with full-thickness macular hole (FTMH). Methods: This retrospective study included 41 eyes of 41 patients with FTMH treated with vitrectomy using the inverted ILM flap technique. Complete ophthalmic examination was performed preoperatively, at 1 week, and at 1, 3, 6, 9, and 12 months after surgery. Results: Postoperative SD-OCT confirmed macular hole (MH) closure in all patients. The mean BCVA improved from 0.7 LogMAR (20/100) preoperatively to 0.5 LogMAR (20/63) postoperatively. In two cases, 7 days after vitrectomy, flap closure was noted. At the final visit after 12 months, the following foveal contours were noted: 14 U-shape (34.1%), 12 irregular (W-shape) (29.3%), and 6 V-shape (14.6%). We observed a type of "plug closure" in 9 (22%) eyes in which hyperproliferation was noted in one eye. Conclusions: The surgeons should be aware of potential hyperproliferation on the retinal surface after the multi-layered flap technique.

Amplified Vasodilatation within the Referred Pain Zone of Trigger Points Is Characteristic of Gluteal Syndrome-A Type of Nociplastic Pain Mimicking Sciatica.

Gluteal syndrome (GS) mimicking sciatica is a new disease that has been recently recognized and included in the International Classification of Diseases, 11th Revision. The present study examines nociplastic pain involvement in GS and sciatica patients using a new Skorupska protocol (SP) test that provokes amplified vasodilatation in the area of expected muscle-referred pain. A positive test is confirmed if there is (i) a development of autonomic referred pain (AURP) and (ii) an increase in the delta of average temperature (Δ₸°) > 0.3 °C at the end of the stimulation and during the observation SP phases. Chronic GS (n = 20) and sciatica (n = 30) patients were examined. The SP test confirmed muscle-referred pain for (i) all GS patients with 90.6% positive thermograms (Δ₸° 0.6 ± 0.8 °C; maximum AURP 8.9 ± 13.6% (both p < 0.05)) and (ii) those sciatica (n = 8) patients who reported pain sensation during the test with 20.6% positive thermograms (Δ₸° 0.7 ± 0.7 °C; maximum AURP 15.1 ± 17.8% (both p < 0.05)). The remaining sciatica (n = 22) patients did not report pain during the test and presented a Δ₸° decrease and the AURP size below 1%. Conclusion: Amplified vasodilatation suggesting nociplastic pain involvement was confirmed for all GS and sciatica patients who reported painful sensations in the zone typical for gluteus minimus referred pain during the test.

The Automatization of a New Thermography Method Using Invasive Nociceptive Stimulation to Confirm an Autonomic Phenomenon within a Trigger Point Referred Pain Zone.

The trigger points (TrPs) related to chronic low back pain that mimic sciatica have been lately recognized and included in the International Classification of Diseases, 11th Revision. This study examined the MATLAB software utility for the objective stratification of low back pain patients using the Minimally Invasive Procedure (MIP). The two diagnostic MIP parameters were: average temperature (ΔTavr) and autonomic referred pain (AURP). Chronic sciatica patients with TrPs (n = 20) and without TrPs (n = 20) were examined using the MIP. A significant increase in both parameters was confirmed for the thigh ROI of the TrP-positive patients, with ΔTavr being the leading parameter (p = 0.016, Exp(ß) = 2.603). A continued significance of both parameters was confirmed from 6'00″ to 15'30″ (p < 0.05). The maximum AURP value was confirmed at 13'30″ (p < 0.05) (TrPs(+) 20.4 ± 19.9% vs. TrPs(-) 3.77 ± 9.14%; p = 0.000; CI (0.347,0.348)).

Total Hemoglobin Mass, Aerobic Capacity, and HBB Gene in Polish Road Cyclists.

Malczewska-Lenczowska, J, Orysiak, J, Majorczyk, E, Zdanowicz, R, Szczepanska, B, Starczewski, M, Kaczmarski, J, Dybek, T, Pokrywka, A, Ahmetov, II, and Sitkowski, D. Total hemoglobin mass, aerobic capacity, and the HBB gene in polish road cyclists. J Strength Cond Res 30(12): 3512-3519, 2016-The relationship between genes, amount of hemoglobin, and physical performance are still not clearly defined. The aim of this study was to examine the association between-551C/T and intron 2, +16 C/G polymorphisms in the beta hemoglobin (HBB) gene and total hemoglobin mass (tHbmass) and aerobic capacity in endurance athletes. Total hemoglobin mass and aerobic capacity indices, i.e.,V[Combining Dot Above]O2max, oxygen uptake at anaerobic threshold (V[Combining Dot Above]O2AT), maximal power output (Pmax), and power at anaerobic threshold (PAT) were determined in 89 young road cyclists, female (n = 39) and male (n = 50), who were genotyped for 2 polymorphisms in the HBB gene. The relative values of aerobic capacity indices differed significantly among intron 2, +16 C/G polymorphisms of the HBB gene only in female cyclists; athletes with GG genotype had significantly higher values of V[Combining Dot Above]O2max (p = 0.003), V[Combining Dot Above]O2AT (p = 0.007), PAT (p = 0.015), and Pmax (p = 0.004) than C carriers. No relationships were found between the C-carrier model (CC + CG vs. GG in the case of intron 2, +16 C/G and CC + CT vs. TT for -551 C/T polymorphisms of the HBB gene) and relative values of tHbmass. Our results demonstrated that the HBB gene could be related to aerobic capacity, but it seems that it does not result from an increase in the amount of hemoglobin in the blood.