Effects of a shock microcycle after COVID-19 lockdown period in elite soccer players.

Objectives: Decreases in physical fitness are inevitable after two to six week period of detraining in athletes. Lockdown period changed the characteristics of soccer players' training. Aim of the study: The aim of our study was to apply a HIIT shock-microcycle (SM) after return to training and assess its effect on players' performance. Equipment and methods: Nineteen elite professional soccer players during the lockdown period (LP) from March to May 2020 (8 weeks) performed 3-4 individual training sessions per week. The training sessions included running boots of anaerobic short and aerobic prolonged duration intervals. Intensity was determined according to lab ergospirometry test 2 weeks before LP. All the players followed an indoor program, 3-6 sessions per week consisted of core, balance and flexibility exercises (∼45 minutes). SM training content was same for both groups and took place the first two weeks after LP, consisted by eight high intensity interval training sessions (HIIT), two technique, two tactical sessions and two days off. Results: Repeated sprint ability mean time (RSAMeanTime) and Repeated sprint ability performance-sprint no 4,5,6 (RSA4,5,6S) improved after SM (P = 0.025, Effect size: r2 = 0.331, P = 0.010, Effect size: r2 = 0.411, p = 0.009, Effect size: r2 = 0.418, P = 0.037, Effect size: r2 = 0.293, respectively. Yo-Yo intermitted recovery test level 2 (YYIR2TotalDistance) that covered by players during the 2nd measurement was 10.8% longer (P = 0.004, Effect size: r2 = 0.483). Also, the YYIR2HeartRateRecovery percentage was lower during the 2nd measurement (P = 0.014, Effect size: r2 = 0.107). Conclusions: These results indicate that SM can improve YYIR2 and RSA performance thus it is a useful tool to regain physical attributes in a short period.

Objectifs: L'altération des capacités physiques est inévitable après une période de deux à six semaines d'absence d'entraînement chez les athlètes. La période de confinement due au COVID19 a changé les caractéristiques de la préparation des joueurs de football. But de l'étude: Le but de notre étude était d'appliquer un microcycle d'entrainement fractionné de haute intensité (HIIT, ou microcycle de choc SM), après le retour à l'entraînement, et d'évaluer ses effets sur les performances des joueurs. Matériel et méthodes: Dix-neuf footballeurs professionnels d'élite ont effectué 3-4 séances d'entraînement individuel par semaine pendant la période de confinement de mars à mai 2020 (LP, 8 semaines). Les séances prévoyaient des exercices de courses à pied par intervalles, de courte et longue durée. L'intensité des exercices évaluée par des tests d'ergospirométrie en laboratoire deux semaines avant la LP. Tous les joueurs ont suivi le programme en salle close (3­6 séances par semaine) comprenant des exercices de base, d'équilibre et de flexibilité (∼45 minutes). Le contenu du HIIT était le même pour les deux groupes et a débuté après la LP, pendant les deux semaines suivant l'entraînement et comprenant 8 sessions de HIIT, 2 sessions d'entrainement technique, 2 sessions de tactiques et 2 jours de congé. Résultats: RSAMeanTime et RSA4,5,6S testé après le HIIT (p = 0.025, p = 0,010, p = 0,009, p = 0,037 respectivement. YYIR2Total Distance: la distance totale parcourue par les joueurs durant la seconde évaluation était plus longue de 10,8 % (p = 0,004). De même, le pourcentage de YYIR2HeartRateRecovery était plus bat durant la seconde évaluation (p = 0,014). Conclusions: Les résultats de l'étude ont démontré que le SM peut améliorer les performances YYIR2 et RSA, et constitue une arme utile pour la régénération des aptitudes physiques dans un espace limité.

Acute partial passive stretching increases range of motion and muscle strength.

AIM: The purpose of this study was to investigate the effects of partial passive stretching (PPS) on peak torque (PT) and joint range of motion (ROM) in healthy subjects. METHODS: Twenty-two males (mean age 20.4±1.0 yrs, height 181.1±4.2 cm and weight 75.8±6.8 kg) participated in the study. Quadriceps and hamstrings PT at different angular velocities was obtained on an isokinetic dynamometer. Standing leg method hop was tested for the stretched and unstretched leg. Each subject performed PPS for 20 seconds. The stretching procedure was repeated 5 times for each muscle group. The whole stretching program lasted for 6 minutes and 20 seconds followed by 5 seconds resting period. RESULTS: Directly after the stretching procedure significant increases were observed of PT in quadriceps and hamstrings, however, only at 300o.s⁻¹ (P<0.05). Joint ROM was increased in all subjects (P<0.05). The distance in single length hop was increased significantly in the stretched leg following stretching (P<0.05). No changes were observed in the unstretched leg. CONCLUSION: Our results indicated that the PPS altered ROM, maximal concentric isokinetic strength at high angle velocities and single length hop only for the stretched leg. These findings suggest that PPS may be an effective technique for enhancing muscle performance.

Deltoid muscle fiber characteristics in adolescent and adult wrestlers.

AIM: The aim of the present study was to examine the adaptation of myosin heavy chain (MHC) isoforms, capillary density and fiber cross sectional area (CSA) of deltoid muscle in adolescent and adult elite Greco-Roman wrestlers. METHODS: Eighteen Greco-Roman wrestlers were divided into two groups: adolescents included 10 athletes (group A) between 14-18 years of age (15.4+/-1.3 yrs) and adults included 8 athletes (group B) between 20-27 years (23.5+/-2.6 yrs). Histochemical analyses were used to determine the muscle fiber type distribution and the muscle fiber cross sectional area. MHC isoform composition was determined with protein electrophoresis, while capillary density (capillary to fiber ratio and capillaries per mm2) analysis was performed with a-amylase Periodic and Schiff staining. RESULTS: Adolescents demonstrated a significantly higher percentage of type I fibers (P<0.05) and type I fiber area (P<0.05) compared to the adults. The percentage of type IIa fiber area were significantly higher in adult wrestlers (P<0.05). MHC I isoforms was significantly higher in adolescents (P<0.05), whereas the MHC isoforms of IIa and IIx did not differ between groups. The capillary density (mm2) were significantly higher (P<0.05) in adolescents compared to adults. CONCLUSION: Our findings suggest that the observed muscle fiber profile in the deltoid muscle of wrestlers may represent an adaptation based on the mechanical and biochemical demands of the long-term training. Such adaptations are linked to the specific characteristics of the training program, the level and the previous training experience of the wrestlers.

Deltoid muscle characteristics in wrestlers.

The purpose of the present study was to investigate the deltoid muscle characteristics of wrestlers. Nine Greco-Roman competitive male wrestlers (mean age 20.1+/-2.7 yrs, height 175+/-0.6 cm, weight 83.2+/-12.5 kg, years of training 7.6+/-2.7 yrs) participated in this study. Six male healthy sedentary students (mean age 21.2+/-0.9 yrs, height 180+/-0.3 cm, weight 80.1+/-9.4 kg) served as controls. Muscle fibre distribution, cross-sectional area (CSA), as well as satellite cells, myonuclei and capillary density per muscle fibre area were determined by immunohistochemistry. Myosin heavy chain MHC isoform composition of single fibres was determined with protein electrophoresis. Immunohistochemical analysis showed that muscle fibre distribution of the MHC I and IIA were significantly higher in wrestlers than in controls (p<0.05). Electrophoretic analysis of single fibres revealed a significantly higher proportion of fibres containing MHC I and IIC in wrestlers (p<0.05). The mean CSA of type IIA fibres and the number of myonuclei per type II was significantly higher in wrestlers (p<0.05). We also found that the number of satellite cells was 2.5 fold higher in wrestlers than in the control group. This study suggests that the observed muscle fibre profile in the deltoid of wrestlers may represent an adaptation based on the specific mechanical and biochemical demands of the long-term training in Greco-Roman wrestling.