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Borough of Bronx, NY, United States

Lehman College is a senior college of the City University of New York in New York, NY, USA. Founded in 1931 as the Bronx campus of Hunter College, the school became an independent college within CUNY in September 1967. The college is named after Herbert H. Lehman, a former New York governor, United States senator, and philanthropist. It is a public, comprehensive, coeducational liberal arts college with more than 90 undergraduate and graduate degree programs and specializations. Wikipedia.

It is well established that regimented resistance training can promote increases in muscle hypertrophy. The prevailing body of research indicates that mechanical stress is the primary impetus for this adaptive response and studies show that mechanical stress alone can initiate anabolic signalling. Given the dominant role of mechanical stress in muscle growth, the question arises as to whether other factors may enhance the post-exercise hypertrophic response. Several researchers have proposed that exercise-induced metabolic stress may in fact confer such an anabolic effect and some have even suggested that metabolite accumulation may be more important than high force development in optimizing muscle growth. Metabolic stress pursuant to traditional resistance training manifests as a result of exercise that relies on anaerobic glycolysis for adenosine triphosphate production. This, in turn, causes the subsequent accumulation of metabolites, particularly lactate and H+. Acute muscle hypoxia associated with such training methods may further heighten metabolic buildup. Therefore, the purpose of this paper will be to review the emerging body of research suggesting a role for exercise-induced metabolic stress in maximizing muscle development and present insights as to the potential mechanisms by which these hypertrophic adaptations may occur. These mechanisms include increased fibre recruitment, elevated systemic hormonal production, alterations in local myokines, heightened production of reactive oxygen species and cell swelling. Recommendations are provided for potential areas of future research on the subject. © 2013 Springer International Publishing Switzerland. Source

Schoenfeld B.J.,Lehman College, CUNY
Journal of Strength and Conditioning Research

Exercise-induced muscle damage (EIMD) occurs primarily from the performance of unaccustomed exercise, and its severity is modulated by the type, intensity, and duration of training. Although concentric and isometric actions contribute to EIMD, the greatest damage to muscle tissue is seen with eccentric exercise, where muscles are forcibly lengthened. Damage can be specific to just a few macromolecules of tissue or result in large tears in the sarcolemma, basal lamina, and supportive connective tissue, and inducing injury to contractile elements and the cytoskeleton. Although EIMD can have detrimental short-term effects on markers of performance and pain, it has been hypothesized that the associated skeletal muscle inflammation and increased protein turnover are necessary for long-term hypertrophic adaptations. A theoretical basis for this belief has been proposed, whereby the structural changes associated with EIMD influence gene expression, resulting in a strengthening of the tissue and thus protection of the muscle against further injury. Other researchers, however, have questioned this hypothesis, noting that hypertrophy can occur in the relative absence of muscle damage. Therefore, the purpose of this article will be twofold: (a) to extensively review the literature and attempt to determine what, if any, role EIMD plays in promoting skeletal muscle hypertrophy and (b) to make applicable recommendations for resistance training program design. © 2012 National Strength and Conditioning Association. Source

Waters B.M.,University of Nebraska - Lincoln | Sankaran R.P.,Lehman College, CUNY
Plant Science

The micronutrients iron (Fe), zinc (Zn), and copper (Cu) are essential for plants and the humans and animals that consume plants. Increasing the micronutrient density of staple crops, or biofortification, will greatly improve human nutrition on a global scale. This review discusses the processes and genes needed to translocate micronutrients through the plant to the developing seeds, and potential strategies for developing biofortified crops. © 2010 Elsevier Ireland Ltd. Source

In humans, regimented resistance training has been shown to promote substantial increases in skeletal muscle mass. With respect to traditional resistance training methods, the prevailing opinion is that an intensity of greater than ~60 % of 1 repetition maximum (RM) is necessary to elicit significant increases in muscular size. It has been surmised that this is the minimum threshold required to activate the complete spectrum of fiber types, particularly those associated with the largest motor units. There is emerging evidence, however, that low-intensity resistance training performed with blood flow restriction (BFR) can promote marked increases in muscle hypertrophy, in many cases equal to that of traditional high-intensity exercise. The anabolic effects of such occlusion-based training have been attributed to increased levels of metabolic stress that mediate hypertrophy at least in part by enhancing recruitment of high-threshold motor units. Recently, several researchers have put forth the theory that low-intensity exercise (≤50 % 1RM) performed without BFR can promote increases in muscle size equal, or perhaps even superior, to that at higher intensities, provided training is carried out to volitional muscular failure. Proponents of the theory postulate that fatiguing contractions at light loads is simply a milder form of BFR and thus ultimately results in maximal muscle fiber recruitment. Current research indicates that low-load exercise can indeed promote increases in muscle growth in untrained subjects, and that these gains may be functionally, metabolically, and/or aesthetically meaningful. However, whether hypertrophic adaptations can equal that achieved with higher intensity resistance exercise (≤60 % 1RM) remains to be determined. Furthermore, it is not clear as to what, if any, hypertrophic effects are seen with lowintensity exercise in well-trained subjects as experimental studies on the topic in this population are lacking. Practical implications of these findings are discussed. © Springer International Publishing Switzerland 2013. Source

It has been well documented in the literature that resistance training can promote marked increases in skeletal muscle mass. Postexercise hypertrophic adaptations are mediated by a complex enzymatic cascade whereby mechanical tension is molecularly transduced into anabolic and catabolic signals that ultimately lead to a compensatory response, shifting muscle protein balance to favor synthesis over degradation. Myocellular signaling is influenced, in part, by the endocrine system. Various hormones have been shown to alter the dynamic balance between anabolic and catabolic stimuli in muscle, helping to mediate an increase or decrease in muscle protein accretion. Resistance training can have an acute impact on the postexercise secretion of several of these hormones including insulin-like growth factor, testosterone, and growth hormone (GH). Studies show that hormonal spikes are magnified after hypertrophy-type exercise that involves training at moderate intensities with shortened rest intervals as compared with high-intensity strength-oriented training. The observed positive relationship between anabolic hormones and hypertrophy-type training has led to the hormone hypothesis, which postulates that acute postexercise hormonal secretions mediate increases in muscle size. Several researchers have suggested that these transient hormonal elevations may be more critical to hypertrophic adaptations than chronic changes in resting hormonal concentrations. Theoretically, high levels of circulating hormones increase the likelihood of interaction with receptors, which may have particular hypertrophic importance in the postworkout period when muscles are primed for anabolism. Moreover, hormonal spikes may enhance intracellular signaling so that postexercise protein breakdown is rapidly attenuated and anabolic processes are heightened, thereby leading to a greater supercompensatory response. Although the hormone hypothesis has received considerable support in the literature, several researchers have questioned its veracity, with some speculating that the purpose of postexercise hormonal elevations is to mobilize fuel stores rather than promote tissue anabolism. Therefore, the purpose of this article will be to critically and objectively review the current literature, and then draw relevant conclusions as to the potential role of acute systemic factors on muscle protein accretion. © 2013 National Strength and Conditioning Association. Source

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