This review discusses previous literature that has examined the influence of muscular strength on various factors associated with athletic performance and the benefits of achieving greater muscular ...strength. Greater muscular strength is strongly associated with improved force-time characteristics that contribute to an athlete's overall performance. Much research supports the notion that greater muscular strength can enhance the ability to perform general sport skills such as jumping, sprinting, and change of direction tasks. Further research indicates that stronger athletes produce superior performances during sport specific tasks. Greater muscular strength allows an individual to potentiate earlier and to a greater extent, but also decreases the risk of injury. Sport scientists and practitioners may monitor an individual's strength characteristics using isometric, dynamic, and reactive strength tests and variables. Relative strength may be classified into strength deficit, strength association, or strength reserve phases. The phase an individual falls into may directly affect their level of performance or training emphasis. Based on the extant literature, it appears that there may be no substitute for greater muscular strength when it comes to improving an individual's performance across a wide range of both general and sport specific skills while simultaneously reducing their risk of injury when performing these skills. Therefore, sport scientists and practitioners should implement long-term training strategies that promote the greatest muscular strength within the required context of each sport/event. Future research should examine how force-time characteristics, general and specific sport skills, potentiation ability, and injury rates change as individuals transition from certain standards or the suggested phases of strength to another.
The ISCHEMIA trial (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) postulated that patients with stable coronary artery disease (CAD) and moderate or ...severe ischemia would benefit from revascularization. We investigated the relationship between severity of CAD and ischemia and trial outcomes, overall and by management strategy.
In total, 5179 patients with moderate or severe ischemia were randomized to an initial invasive or conservative management strategy. Blinded, core laboratory-interpreted coronary computed tomographic angiography was used to assess anatomic eligibility for randomization. Extent and severity of CAD were classified with the modified Duke Prognostic Index (n=2475, 48%). Ischemia severity was interpreted by independent core laboratories (nuclear, echocardiography, magnetic resonance imaging, exercise tolerance testing, n=5105, 99%). We compared 4-year event rates across subgroups defined by severity of ischemia and CAD. The primary end point for this analysis was all-cause mortality. Secondary end points were myocardial infarction (MI), cardiovascular death or MI, and the trial primary end point (cardiovascular death, MI, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest).
Relative to mild/no ischemia, neither moderate ischemia nor severe ischemia was associated with increased mortality (moderate ischemia hazard ratio HR, 0.89 95% CI, 0.61-1.30; severe ischemia HR, 0.83 95% CI, 0.57-1.21;
=0.33). Nonfatal MI rates increased with worsening ischemia severity (HR for moderate ischemia, 1.20 95% CI, 0.86-1.69 versus mild/no ischemia; HR for severe ischemia, 1.37 95% CI, 0.98-1.91;
=0.04 for trend,
=NS after adjustment for CAD). Increasing CAD severity was associated with death (HR, 2.72 95% CI, 1.06-6.98) and MI (HR, 3.78 95% CI, 1.63-8.78) for the most versus least severe CAD subgroup. Ischemia severity did not identify a subgroup with treatment benefit on mortality, MI, the trial primary end point, or cardiovascular death or MI. In the most severe CAD subgroup (n=659), the 4-year rate of cardiovascular death or MI was lower in the invasive strategy group (difference, 6.3% 95% CI, 0.2%-12.4%), but 4-year all-cause mortality was similar.
Ischemia severity was not associated with increased risk after adjustment for CAD severity. More severe CAD was associated with increased risk. Invasive management did not lower all-cause mortality at 4 years in any ischemia or CAD subgroup. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01471522.
The current manuscript has been adapted from the official position statement of the UK Strength and Conditioning Association on youth resistance training. It has subsequently been reviewed and ...endorsed by leading professional organisations within the fields of sports medicine, exercise science and paediatrics. The authorship team for this article was selected from the fields of paediatric exercise science, paediatric medicine, physical education, strength and conditioning and sports medicine.
This review article examines previous weightlifting literature and provides a rationale for the use of weightlifting pulling derivatives that eliminate the catch phase for athletes who are not ...competitive weightlifters. Practitioners should emphasize the completion of the triple extension movement during the second pull phase that is characteristic of weightlifting movements as this is likely to have the greatest transference to athletic performance that is dependent on hip, knee, and ankle extension. The clean pull, snatch pull, hang high pull, jump shrug, and mid-thigh pull are weightlifting pulling derivatives that can be used in the teaching progression of the full weightlifting movements and are thus less complex with regard to exercise technique. Previous literature suggests that the clean pull, snatch pull, hang high pull, jump shrug, and mid-thigh pull may provide a training stimulus that is as good as, if not better than, weightlifting movements that include the catch phase. Weightlifting pulling derivatives can be implemented throughout the training year, but an emphasis and de-emphasis should be used in order to meet the goals of particular training phases. When implementing weightlifting pulling derivatives, athletes must make a maximum effort, understand that pulling derivatives can be used for both technique work and building strength-power characteristics, and be coached with proper exercise technique. Future research should consider examining the effect of various loads on kinetic and kinematic characteristics of weightlifting pulling derivatives, training with full weightlifting movements as compared to training with weightlifting pulling derivatives, and how kinetic and kinematic variables vary between derivatives of the snatch.
Myelofibrosis is a myeloid malignancy associated with anemia, splenomegaly, and constitutional symptoms. Patients frequently harbor JAK-STAT activating mutations that are sensitive to TG101348, a ...selective small-molecule Janus kinase 2 (JAK2) inhibitor.
In a multicenter phase I trial, oral TG101348 was administered once a day to patients with high- or intermediate-risk primary or post-polycythemia vera/essential thrombocythemia myelofibrosis.
Fifty-nine patients were treated, including 28 in the dose-escalation phase. The maximum-tolerated dose was 680 mg/d, and dose-limiting toxicity was a reversible and asymptomatic increase in the serum amylase level. Forty-three patients (73%) continued treatment beyond six cycles; the median cumulative exposure to TG101348 was 380 days. Adverse events included nausea, vomiting, diarrhea, anemia, and thrombocytopenia; corresponding grades 3 to 4 incidence rates were 3%, 3%, 10%, 35%, and 24%. TG101348 treatment had modest effect on serum cytokine levels, but greater than half of the patients with early satiety, night sweats, fatigue, pruritus, and cough achieved rapid and durable improvement in these symptoms. By six and 12 cycles of treatment, 39% and 47% of patients, respectively, had achieved a spleen response per International Working Group criteria. The majority of patients with leukocytosis or thrombocytosis at baseline (n = 28 and n = 10, respectively) achieved normalization of blood counts after six (57% and 90%, respectively) and 12 (56% and 88%, respectively) cycles. A significant decrease in JAK2 V617F allele burden was observed at 6 months in mutation-positive patients (n = 51; P = .04), particularly in the subgroup with allele burden greater than 20% (n = 23; P < .01); the decrease was durable at 12 months.
TG101348 is well tolerated and produces significant reduction in disease burden and durable clinical benefit in patients with myelofibrosis.
Muscle fiber composition correlates with insulin resistance, and exercise training can increase slow-twitch (type I) fibers and, thereby, mitigate diabetes risk. Human skeletal muscle is made up of ...three distinct fiber types, but muscle contains many more isoforms of myosin heavy and light chains, which are coded by 15 and 11 different genes, respectively. Laser capture microdissection techniques allow assessment of mRNA and protein content in individual fibers. We found that specific human fiber types contain different mixtures of myosin heavy and light chains. Fast-twitch (type IIx) fibers consistently contained myosin heavy chains 1, 2, and 4 and myosin light chain 1. Type I fibers always contained myosin heavy chains 6 and 7 (MYH6 and MYH7) and myosin light chain 3 (MYL3), whereas MYH6, MYH7, and MYL3 were nearly absent from type IIx fibers. In contrast to cardiomyocytes, where MYH6 (also known as α-myosin heavy chain) is seen solely in fast-twitch cells, only slow-twitch fibers of skeletal muscle contained MYH6. Classical fast myosin heavy chains (MHC1, MHC2, and MHC4) were present in variable proportions in all fiber types, but significant MYH6 and MYH7 expression indicated slow-twitch phenotype, and the absence of these two isoforms determined a fast-twitch phenotype. The mixed myosin heavy and light chain content of type IIa fibers was consistent with its role as a transition between fast and slow phenotypes. These new observations suggest that the presence or absence of MYH6 and MYH7 proteins dictates the slow- or fast-twitch phenotype in skeletal muscle.
Borderline personality disorder (BPD) is fundamentally a syndrome composed of symptoms (primarily of emotional dysregulation) and a number of true personality traits (such as inordinate anger, ...impulsivity, and a tendency to stress-related paranoid ideation). Whereas schizotypal personality disorder, with its cognitive peculiarities (ideas of reference, odd beliefs, eccentric speech), is closely linked as a genetic condition-"borderline" to the major condition schizophrenia-BPD is less closely linked to bipolar disorder. Some cases of BPD are linked genetically to and are in the "border" of bipolar disorder. But the condition can also arise from adverse post-natal factors: parental cruelty or neglect, or incest. In some BPD patients, both are present: risk genes for bipolar disorder and adverse conditions within the family. The genetic risk is often overlooked. To avoid this, initial evaluations should always include a careful and extensive family history for mood disorders, and should extend out to grandparents, aunts, uncles, and cousins. Where the history suggests a genetic link to bipolar disorder, a mood stabilizer such as lithium or lamotrigine, even in modest doses, may be particularly beneficial, more so than conventional antidepressants. In some patients, ADHD was present in childhood, BPD was diagnosed during or after puberty, and a form of bipolar disorder becomes apparent during their 20s. As for the psychotherapeutic component, the patient's cognitive style and capacity for introspection will help determine whether a primarily expressive (psychoanalytically oriented) technique is preferable or a primarily cognitive-behavioral technique. Flexibility is necessary, since during emotional crises, supportive and limit-setting interventions will be needed, along with psychotropic medications, and where necessary, programs to help combat substance abuse (which is common among patients with BPD).
The process of strength-power training and the subsequent adaptation is a multi-factorial process. These factors range from the genetics and morphological characteristics of the athlete to how a ...coach selects, orders, and doses exercises and loading patterns. Consequently, adaptation from these training factors may largely relate to the mode of delivery, in other words, programming tactics. There is strong evidence that the manner and phases in which training is presented to the athlete can make a profound difference in performance outcome. This discussion deals primarily with block periodization concepts and associated methods of programming for strength-power training within track and field. 2015 Production and hosting by Elsevier B.V. on behalf of Shanghai University of Sport.
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