Recovery kinetics of knee flexor and extensor strength after a football match

© 2015 The Authors. Published by PLOS. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1371/journal.pone.0128072We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60°/s and for 60h at 180°/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180°/s and in dominant limb, d) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level.Published versio

Oxidative stress and antioxidant mechanism following resistance exercise of progressively increased volume

Intense exercise increases the shaping of free radicals in the muscles. Chronis exercise can lead to overtraining syndrome which is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. Purpose: The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Methods: Twelve males (21,3 ± 2,3 yrs) participated in a 12-wk resistance training consisting of five 3-wk periods. The training protocol comprises 7 multi-joint exercises. During the first period T1, participants lifted 2 tones/wk, in T2, 8 tones, in T3, 14 tones, in T4, the participants lifted only 2 tones/wk while the following 3-wk was the period of complete restBlood/urine samples were collected at baseline and 96 hours following the last training session of each period. A day after the collection, tests as 1 RM strength, anaerobic power and jumping ability were performed. Results: The results of those tests showed an increased after T2 and declined thereafter indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), PC (73%, catalase (96%), GPX, and GSSG (25%) and a decline of GSH (31%), GSH/GSSG (56%), and TAC. Isoprostanes and GSH/GSSG were highly (r = 0 764-0 911) correlated with performance drop and training volume increase. Conclusion: overtraining induces a marked response of oxidative stress biomarkers which, in some cases, was proportional to training load suggesting that they may serve as diagnostic tools for overtraining diagnosis.Η έντονη άσκηση αυξάνει τον σχηματισμό ελευθέρων ριζών μέσα στους μύες. Η χρόνια έντονη άσκηση μπορεί να οδηγήσει στο σύνδρομο της υπερπροπόνησης το οποίο χαρακτηρίζεται από την μείωση της απόδοσης και τη παροδική φλεγμονή, η οποία ακολουθείται από περιόδους προπόνησης με σοβαρές συνέπειες στην υγεία των αθλητών. Μέχρι σήμερα, δεν υπάρχει κανένας δείκτης διάγνωσης της υπερπροπόνησης. Στόχος: Η παρούσα έρευνα εξετάζει τις ανταποκρίσεις των δεικτών του οξειδωτικού στρες σ' ένα πρωτόκολλο άσκησης αντιστάσεων αυξανόμενου και μειωμένου προπονητικού όγκου και έντασης. Μεθοδολογία: Δώδεκα άντρες ηλικίας 23,1 ± 2,3 έτη συμμετείχαν σε ένα πρόγραμμα αντιστάσεων 12 εβδομάδων το οποίο αποτελούνταν από 5 περιόδους των 3 εβδομάδων. Το πρωτόκολλο περιελάμβανε 7 πολυαρθρικές ασκήσεις αντιστάσεων. Στη πρώτη περίοδο Τ1, οι συμμετέχοντες σήκωσαν 2 τόνους/εβδομάδα, στη δεύτερη Τ2, 8 τόνους, στη Τ3 περίοδο, 14 τόνους, στη Τ4 περίοδο 2 τόνους/εβδομάδα, ενώ οι 3 εβδομάδες της τελευταίας περιόδου R, δεν περιελάμβαναν καθόλου προπόνηση. Δειγματοληψίες από αίμα και ούρα συλλέχθηκαν πριν ξεκινήσει το προπονητικό πρωτόκολλο, και 96 ώρες μετά από κάθε προπονητική περίοδο. Μία μέρα μετά τη κάθε δειγματοληψία πραγματοποιήθηκαν τεστ αξιολόγησης της απόδοσης όπως 1 μέγιστη επανάληψη, αναερόβια ισχύ και ικανότητα άλματος. Αποτελέσματα: Από τα αποτελέσματα φάνηκε η αύξηση της απόδοσης στη Τ2 περίοδο, η οποία μειώθηκε στη συνέχεια υποδεικνύοντας ίσως την εμφάνιση υπερπροπόνησης (Τ3). Κατά τη περίοδο αυτή, παρουσιάστηκαν φαινόμενα παρατεινόμενης λευκοκύττωσης, αύξησης των Ρ2-ισοπροστάνιων κατά 7 φορές καθώς και των ουσιών που αντιδρούν με το θειοβαρβιτουρικό οξύ κατά 56%. Επιπλέον, τα πρωτεϊνικά καρβονύλια αυξήθηκαν κατά 73%, η καταλάση 96%, η οξειδωμένη γλουταθειόνη 25%, ενώ μικρή αύξηση είχε η υπεροξειδάση της γλουταθειόνης. Αντιθέτως, υπήρξε μείωση στα επίπεδα της ανηγμένης γλουταθειόνης κατά 31% και τις αναλογίας ανηγμένη προς οξειδωμένη γλουταθειόνη κατά 56%. Μικρή μείωση εμφάνισε η ολική αντιοξειδωτική ικανότητα των συμμετεχόντων. Αξιοσημείωτο είναι το γεγονός της υψηλής συσχέτισης μεταξύ των F2-ισοπροστάνιων και του λόγου των γλουταθειόνων με τη πτώση της απόδοσης και την αύξηση του προπονητικού όγκου. Συμπεράσματα: η υπερπροπόνηση προκαλεί μία αξιοσημείωτη ανταπόκριση στους δείκτες οξειδωτικού στρες, η οποία σε ορισμένες περιπτώσεις, εμφανίστηκε να είναι ανάλογη του προπονητικού φορτίου. Το εύρημα αυτό, ίσως τελικά προσδιορίζει ένα σημαντικό εργαλείο για τη διάγνωση της υπερπροπόνησης

Cell-free plasma DNA as a novel marker of aseptic inflammation severity related to exercise overtraining

Background: Circulating free plasma DNA is implicated in conditions associated with tissue injury, including exercise-induced inflammation, and thus is a potential marker for athletic overtraining. Methods: We measured free plasma DNA along with C-reactive protein (CRP), creatine kinase (CK), and uric acid (UA) in 17 recreationally trained men participating in a 12-week resistance training regimen (8 resistance multi-joint exercises selected to stress the entire musculature: bench press, squat, leg press, snatch, hang clean, dead lifts, barbell arm curls, and rowing), consisting of 4 training periods (t1, t2, t3, and t4). Results: Plasma DNA concentrations increased markedly after t1, t2, and t3 and returned to baseline after t4. There were substantial differences between t2 and t1 and between t3 and t2 plasma DNA concentrations. CRP increased by 300% after t2 and by 400% after t3 (there was no difference between t2 and t3 CRP values) compared with baseline (t0). CK increased only after t3. UA increased after t2 and t3, with a greater increase after t3. Conclusions: This study demonstrates that, after chronic excessive resistance exercise, plasma DNA concentrations increase in proportion to training load, suggesting that plasma DNA may be a sensitive marker for overtraining-induced inflammation. (c) 2006 American Association for Clinical Chemistry

Oxidative stress biomarkers responses to physical overtraining: Implications for diagnosis

Overtraining syndrome is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Twelve males (21.3 +/- 2.3 years) participated in a 12-week resistance training consisting of five 3-week periods (T1, 2 tones/week; T2, 8 tones/week; T3, 14 tonesAveek: T4, 2 tonesAveek), followed by a 3-week period of complete rest. Blood/urine samples were collected at baseline and 96 h following the last training session of each period. Performance (strength, power, jumping ability) increased after T2 and declined thereafter, indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), protein carbonyls (73%), catalase (96%), glutathione peroxidase, and oxidized glutathione (GSSG) (25%) and a decline of reduced glutathione (GSH) (31%), GSH/GSSG (56%), and total antioxidant capacity. lsoprostanes and GSH/GSSG were highly (r=0.764-0.911) correlated with performance drop and training Volume increase. In conclusion, overtraining induces a marked response of oxidative stress biomarkers, which, in some cases, was proportional to training load, Suggesting that they may serve as a tool for overtraining diagnosis. (c) 2007 Elsevier Inc. All rights reserved

Clinical Score Predicting Long-Term Survival after Repeat Resection for Recurrent Adrenocortical Carcinoma

BACKGROUND: Adrenocortical carcinoma (ACC) is an aggressive malignancy typically resistant to chemotherapy and radiation. Surgery, even in the setting of locally recurrent or metastatic disease, remains the only potentially curative option. However, the subset of patients who will benefit from repeat resection in this setting remains ill defined. The objective of this study was to propose a prognostic clinical score that facilitates selection of patients for repeat resection of recurrent ACC. STUDY DESIGN: Patients who underwent curative-intent repeat resection for recurrent ACC at 1 of 13 academic medical centers participating in the US ACC Study Group were identified. End points included morbidity, mortality, and overall survival. RESULTS: Fifty-six patients underwent repeat curative-intent resection for recurrent ACC (representing 21% of 265 patients who underwent resection for primary ACC) from 1997 to 2014. Median age was 52 years. Sites of resected recurrence included locoregional only (54%), lung only (14%), liver only (12%), combined locoregional and lung (4%), combined liver and lung (4%), and other distant sites (12%). Thirty-day morbidity and mortality rates were 40% and 5.4%, respectively. Cox regression analysis revealed that the presence of multifocal recurrence, disease-free interval <12 months, and extrapulmonary distant metastases were independent predictors of poor survival. A clinical score consisting of 1-point each for the 3 variables demonstrated good discrimination in predicting survival after repeat resection (5-year: 72% for 0 points, 32% for 1 point, 0% for 2 or 3 points; p = 0.0006, area under the curve = 0.78). CONCLUSIONS: Long-term survival after repeat resection for recurrent ACC is feasible when 2 of the following factors are present: solitary tumor, disease-free interval >12 months, and locoregional or pulmonary recurrence

GPS-measured activity profile of the experimental group during the football match.

<p>GPS, global positioning system.</p><p>GPS-measured activity profile of the experimental group during the football match.</p

The contents and duration of daily training sessions performed during the post-match period.

<p>The contents and duration of daily training sessions performed during the post-match period.</p

Changes of functional ratio in response to a football match.

<p>KF_ecc/KE_con, functional ratio; h, hours; ¹Significant difference with baseline; ²significant difference between groups; ³significant difference between dominant and non-dominant limb at corresponding time; ⁴greater decline in functional ration compared to conventional ratio at corresponding time;⁵greater decline at 180°/s compared to that at 60°/s at corresponding time.</p