SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Mixed martial arts

28

The purpose of this study was to examine the effects of a seven-week, practical blood flow restriction (BFR) protocol used in conjunction with a strength training program on measures of muscular strength and size in collegiate American football players. Sixty-two participants were divided into four groups. Three groups completed a traditional upper- and lower-body split strength program. Two of these groups also completed supplemental lifting sessions. Of these two, one completed the additional lifts with blood flow restriction. The final group completed a modified training program, followed by the supplemental lifts, with blood flow restriction. The supplemental lifting protocol consisted of bench press and squat, utilizing 20% 1RM for four sets with 30 repetitions performed in the first set and 20 repetitions performed in the following three. Each set was separated by 45 seconds of rest. The supplemental bench press was completed at the end of upper-body days, and the squat at the end of lower-body days. Dependent measures were taken prior to the start of the program and again upon conclusion: upper- and lower-body girths, 1RM bench and squat. Results of a 4 X 2 mixed model MANCOVA revealed a significant difference for the interaction on the dependent variables. Follow-up univariate ANOVAs indicated a significant difference for 1RM squat. This suggests that a practical BFR program used in addition to a traditional strength training program can be effective at increasing 1RM squat performance. The use of elastic knee wraps makes BFR a feasible training option for coaches and athletes.

Concepts: Hematology, Strength training, Isometric exercise, Powerlifting, Physical strength, Mixed martial arts, Weight training exercises, Spotting

26

Objectives To determine whether the outcome of drug studies influenced submission and/or acceptance rates for publication in peer reviewed medical journals.Design A six year retrospective review of publication status by study outcome for all human drug research studies conducted by a single industry sponsor (GlaxoSmithKline) that completed from 1 January 2009 to 30 June 2014 and were therefore due for manuscript submission (per the sponsor’s policy) to peer reviewed journals within 18 months of study completion-that is, 31 December 2015. In addition, manuscripts from studies completing after 30 June 2014 were included irrespective of outcome if they were submitted before 31 December 2015.Setting Studies conducted by a single industry sponsor (GlaxoSmithKline)Studies reviewed 1064 human drug research studies.Main outcome measures All studies were assigned a publication status at 26 February 2016 including (as applicable): study completion date, date of first primary manuscript submission, number of submissions, journal decision(s), and publication date. All studies were also classified with assessors blinded to publication status as “positive” (perceived favorable outcome for the drug under study), “negative” (perceived unfavorable outcome for the drug under study), mixed, or non-comparative based on the presence and outcome of the primary outcome measure(s) for each study. “Negative” studies included safety studies in which the primary outcome was achieved but was adverse for the drug under study. For the total cohort and each of the four study outcomes, measures included descriptive statistics for study phase, time from study completion to submission and publication, and number and outcome (accepted/rejected) of publication submissions.Results Of the 1064 studies (phase I-IV, interventional and non-interventional) included, 321 had study outcomes classified as positive, 155 as negative, 52 as mixed, and 536 as non-comparative. At the time of publication cut-off date (26 February 2016), 904 (85%) studies had been submitted for publication as full manuscripts and 751 (71%) had been successfully published or accepted, with 100 (9%) still under journal review. An additional 77 (7%) studies were conference abstracts and were not included in submission or publication rates. Submission rates by study outcome were 79% for the 321 studies with positive outcomes, 92% for the 155 with negative outcomes, 94% for the 52 with mixed outcomes, and 85% for the 536 non-comparative studies; while rates of publication at the cut-off date were 66%, 77%, 77%, and 71%, respectively. Median time from study completion to submission was 537 days (interquartile range 396-638 days) and 823 days (650-1063 days) from completion to publication, with similar times observed across study outcomes. First time acceptance rates were 56% for studies with positive outcomes and 48% for studies with negative outcomes. Over 10% of studies across all categories required three or more submissions to achieve successful publication. At the time of analysis, 83 studies had not been submitted for publication, including 49 bioequivalence studies with positive outcomes and 33 non-comparative studies. Most studies (98%, 1041/1064) had results posted to one or more public registers, including all studies subject to FDAAA (Food and Drug Administration Amendments Act) requirements for posting to www.clinicaltrials.govConclusions Over the period studied, there was no evidence of submission or publication bias: 92% of studies with negative outcomes were submitted for publication by the cut-off date versus 79% of those with positive outcomes. Publication rates were slightly higher for studies with a negative (that is, unfavorable) outcome compared with a positive outcome, despite a slightly lower rate of acceptance at first submission. Many studies required multiple submission attempts before they were accepted for publication. Analyses focusing solely on publication rates do not take into account unsuccessful efforts to publish. Sponsors and journal editors should share similar information to contribute to better understanding of issues and barriers to full transparency.

Concepts: Academic publishing, Peer review, Cultural studies, Outcome, Peer-to-peer, Mixed martial arts, 2016, 2015

24

Although caffeine is one of the most commonly used substances in combat sports, information about its ergogenic effects on these disciplines is very limited. The aim of this investigation was to determine the effectiveness of ingesting a moderate dose of caffeine to enhance overall performance during a simulated Brazilian Jiu-jitsu (BJJ) competition.

Concepts: Effect, Caffeine, Brazil, Mixed martial arts, Judo, Combat sports, Jujutsu, Brazilian Jiu-Jitsu

22

Local infiltration analgesia (LIA) with liposomal bupivacaine (LB) in patients undergoing total knee arthroplasty (TKA) has yielded mixed results. The PILLAR study, which was designed to minimize limitations associated with previous studies, compared the effects of LIA with or without LB on pain scores, opioid consumption, including proportion of opioid-free patients, time to first opioid rescue, and safety after primary unilateral TKA.

Concepts: Randomized controlled trial, Local anesthesia, Opioid, Pain, Cultural studies, Knee replacement, Mixed martial arts, The Pillar

22

Scientific information about the effects of caffeine intake on combat sport performance is scarce and controversial. The aim of this study was to investigate the effectiveness of caffeine to improve Brazilian Jiu-jitsu (BJJ)-specific muscular performance. Fourteen male and elite BJJ athletes (29.2 ± 3.3 years; 71.3 ± 9.1 kg) participated in a randomized double-blind, placebo-controlled and crossover experiment. In two different sessions, BJJ athletes ingested 3 mg kg(-1) of caffeine or a placebo. After 60 min, they performed a handgrip maximal force test, a countermovement jump, a maximal static lift test and bench-press tests consisting of one-repetition maximum, power-load, and repetitions to failure. In comparison to the placebo, the ingestion of the caffeine increased: hand grip force in both hands (50.9 ± 2.9 vs. 53.3 ± 3.1 kg; respectively p < .05), countermovement jump height (40.6 ± 2.6 vs. 41.7 ± 3.1 cm; p = .02), and time recorded in the maximal static lift test (54.4 ± 13.4 vs. 59.2 ± 11.9 s; p < .01).The caffeine also increased the one-repetition maximum (90.5 ± 7.7 vs. 93.3 ± 7.5 kg; p = .02), maximal power obtained during the power-load test (750.5 ± 154.7 vs. 826.9 ± 163.7 W; p < .01) and mean power during the bench-press exercise test to failure (280.2 ± 52.5 vs. 312.2 ± 78.3 W; p = .04). In conclusion, the pre-exercise ingestion of 3 mg kg(-1) of caffeine increased dynamic and isometric muscular force, power, and endurance strength in elite BJJ athletes. Thus, caffeine might be an effective ergogenic aid to improve physical performance in BJJ.

Concepts: Clinical trial, Caffeine, Brazil, Grip strength, Mixed martial arts, Nootropic, Judo, Jujutsu

8

BACKGROUND:Mixed martial arts (MMA) is a full combative sport with a recent global increase in popularity despite significant scrutiny from medical associations. To date, the empirical research of the risk of head injuries associated with this sport is limited. Youth and amateur participation is growing, warranting investigation into the burden and mechanism of injuries associated with this sport. PURPOSE:(1) To determine the incidence, risk factors, and characteristics of knockouts (KOs) and technical knockouts (TKOs) from repetitive strikes in professional MMA; and (2) to identify the mechanisms of head trauma and the situational factors that lead to KOs and TKOs secondary to repetitive strikes through video analysis. STUDY DESIGN:Descriptive epidemiology study. METHODS:Competition data and video records for all KOs and TKOs from numbered Ultimate Fighting Championship MMA events (n = 844) between 2006 to 2012. Analyses included (1) multivariate logistic regression to investigate factors associated with an increased risk of sustaining a KO or TKO secondary to repetitive strikes and (2) video analysis of all KOs and TKOs secondary to repetitive strikes with descriptive statistics. RESULTS:During the study period, the KO rate was 6.4 per 100 athlete-exposures (AEs) (12.7% of matches), and the rate of TKOs secondary to repetitive strikes was 9.5 per 100 AEs (19.1% of matches), for a combined incidence of match-ending head trauma of 15.9 per 100 AEs (31.9% of matches). Logistic regression identified that weight class, earlier time in a round, earlier round in a match, and older age were risk factors for both KOs and TKOs secondary to repetitive strikes. Match significance and previously sustained KOs or TKOs were also risk factors for KOs. Video analysis identified that all KOs were the result of direct impact to the head, most frequently a strike to the mandibular region (53.9%). The average time between the KO-strike and match stoppage was 3.5 seconds (range, 0-20 seconds), with losers sustaining an average of 2.6 additional strikes (range, 0-20 strikes) to the head. For TKOs secondary to strikes, in the 30-second interval immediately preceding match stoppage, losers sustained, on average, 18.5 strikes (range, 5-46 strikes), with 92.3% of these being strikes to the head. CONCLUSION:Rates of KOs and TKOs in MMA are higher than previously reported rates in other combative and contact sports. Public health authorities and physicians should be cognizant of the rates and mechanisms of head trauma. Preventive measures to lessen the risks of head trauma for those who elect to participate in MMA are described.

Concepts: Epidemiology, Knockout, Mixed martial arts, Wrestling, Grappling, Combat sport, Martial arts, Ultimate Fighting Championship

7

One of the rationales behind using strength training in the treatment of adolescents with Patellofemoral Pain (PFP) is that reduced strength of the lower extremity is a risk factor for PFP and a common deficit. This rationale is based on research conducted on adolescents >15 years of age but has never been investigated among young adolescents with PFP.

Concepts: Sartorius muscle, Physical strength, Mixed martial arts

4

Mixed martial arts (MMA) is an increasingly popular combative sport involving aggressive techniques that present substantial injury risk. We examined the incidence and types of injuries sustained in MMA fights and compared this with injuries sustained in boxing matches.

Concepts: Kick, Mixed martial arts, Wrestling, Grappling, Combat sport, Martial arts, Combat sports, Hand to hand combat

4

While core stiffness enhances athletic performance traits controversy exists regarding the effectiveness of isometric vs dynamic core training methods. This study aimed to determine if long term changes in stiffness can be trained, and if so, what is the most effective method. Twenty four healthy male subjects (23 ± 3 years, 1.8 ± 0.06 m, 77.5 ± 10.8 kg) were recruited for passive and active stiffness measurements before and after a six week core training intervention. Twelve subjects (22 ± 2 years, 1.8 ± 0.08 m, 78.3 ± 12.3 kg) were considered naïve to physical and core exercise. The other twelve subjects (24 ± 3 years, 1.8 ± 0.05 m, 76.8 ± 9.7 kg) were Muay Thai athletes (savvy). A repeated measures design compared core training methods (Isometric vs. Dynamic, with a Control group) and subject training experience (naïve vs. savvy) before and after a six week training period. Passive stiffness was assessed on a ‘frictionless’ bending apparatus and active stiffness assessed via a quick release mechanism. Passive stiffness increased following the isometric training protocol. Dynamic training produced a smaller effect and as expected there was no change in the Control group. Active stiffness did not change in any group. Comparisons between subject and training groups did not reveal any interactions. Thus, an isometric training approach was superior in terms of enhancing core stiffness. This is important since increased core stiffness enhances load bearing ability, arrests painful vertebral micromovements and enhances ballistic distal limb movement. This may explain the efficacy reported for back and knee injury reduction.

Concepts: Effectiveness, Exercise, Efficacy, Strength training, Repeated measures design, Thailand, Mixed martial arts, Muay Thai

4

The purpose of this study was to characterize the magnitude of acute weight gain (AWG) and dehydration in mixed martial arts (MMA) fighters prior to competition. Urinary measures of hydration status and body mass were determined ∼24 h prior and then again ∼2 h prior to competition in 40 MMA fighters (Mean ± SE, age: 25.2 ± 0.65 yr, height: 1.77 ± 0.01 m, body mass: 75.8 ± 1.5 kg). AWG was defined as the amount of body weight the fighters gained in the ∼22 h period between the official weigh-in and the actual competition. On average, the MMA fighters gained 3.40 ± 2.2 kg or 4.4% of their body weight in the ∼22 h period prior to competition. Urine specific gravity significantly decreased (P < 0.001) from 1.028 ± 0.001 to 1.020 ± 0.001 during the ∼22 h rehydration period. Results demonstrated that 39% of the MMA fighters presented with a Usg of greater than 1.021 immediately prior to competition indicating significant or serious dehydration. MMA fighters undergo significant dehydration and fluctuations in body mass (4.4% avg.) in the 24 h period prior to competition. Urinary measures of hydration status indicate that a significant proportion of MMA fighters are not successfully rehydrating prior to competition and subsequently are competing in a dehydrated state. Weight management guidelines to prevent acute dehydration in MMA fighters are warranted to prevent unnecessary adverse health events secondary to dehydration.

Concepts: Urine, Mass, Dehydration, Weight gain, Body weight, Rehydration, Mixed martial arts, Martial arts