Monday, 20 October 2014

The milestones of sexual development model


The men and women who come to us for help are profoundly vulnerable. They feel broken, unable to enjoy the basic human pleasure of being sexual. Clinically, cases which first appear to be simple dysfunction may later reveal extensive defects in sexual development. The focus of this article is on deeply troubled men and women with intrapsychic obstacles to intimacy stemming from family-of-origin issues.

Some of our most blocked patients experienced sexual abuse, and appropriately staged treatment for them is well defined (Maltz, 2001). However, perhaps two thirds of them were not sexually abused, yet standard behavioral exercises are too advanced and inappropriate for them. How can we identify and help these clients, whose sexuality never developed normally or whose sexual identity never evolved?

Read the rest here.

Monday, 13 October 2014

Does strength training improve running performance?

While there has been considerable research on the effects of weight training on endurance performance, there has not been a large amount of research that has actually measured changes in performance when resistance training is added to an endurance athletes training program.  Generally those research studies that have examined markers of performance such as VO2max, lactate threshold, or running economy find that weight training is a benefit to endurance athletes.  Research that evaluates actual performance changes supports this view and indicates that resistance training is likely to improve performance, especially at running distances of 10k and less.  As the competitive distance increases it is likely that resistance training has a decreasing effect on performance. 

Considering all the data, my recommendation is for the addition of 1-2 days per week of resistance training to your training program, especially if you typically compete at distances of 10k or less.

American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention

ACS Guidelines on Nutrition and Physical Activity for Cancer Prevention
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Exercise interventions on health-related quality of life for people with cancer during active treatment

Mishra SI1, Scherer RW, Snyder C, Geigle PM, Berlanstein DR, Topaloglu O.

Cochrane Database Syst Rev. 2012 Aug 15;8:CD008465. doi: 10.1002/14651858.CD008465.pub2.

Wednesday, 1 October 2014

Neural adaptations to resistive exercise: mechanisms and recommendations for training practices

Gabriel DA1, Kamen G, Frost G.

Sports Med. 2006;36(2):133-49.


It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. 

However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.

PMID: 16464122 [PubMed - indexed for MEDLINE]

Life's Greatest Miracle

A sequel to one of the most popular NOVAs of all time, "Miracle of Life," this Emmy Award-winning program tracks human development from embryo to newborn using the extraordinary microimagery of Swedish photographer Lennart Nilsson.