Latest News & Research: 20 August 2019
This week: Focusing on movement instead of muscle may enhance weightlifting performance • Reduced carb intake improves type 2 diabetes blood sugar regulation • Age, gender and culture influence how much sleep we get
Focusing on movement instead of muscle may enhance weightlifting performance
New analysis published in Frontiers in Sports and Active Living, suggests that to lift heavier, or longer, it is better to focus on moving the weight itself rather than the muscles.
Proponents of the mind-muscle connection cite increased muscle activity, when focusing on specific muscles while lifting, as evidence of benefit. That increased activity might just translate to increased muscle hypertrophy, but put another way: mind-muscle connection makes you expend more effort to lift the same weight.
‘The higher overall muscle activity with an internal 'muscle focus' is not specific to the muscles mentally isolated during lifting’ according to review author Professor David Neumann, of Griffith University in Queensland; ‘Rather, it seems to represent increased activity of non-target muscles, too.’
In contrast, studies have consistently shown that when weightlifters instead focus their attention on the external effects of their efforts, such as the movement of a barbell, lifts are done more economically and with less effort.
‘It appears that this external focus allows automatic control processes to operate, removing the attentional demands and mechanical inefficiency of conscious muscular control’ said Neumann.
In any case, as the load increases - at 80% of maximum effort in one bench press study - the muscle activity advantage of a muscle focus, over an external focus, seems to disappear altogether.
Neumann recommended an external focus, on moving a load, to maximise athletes' performance in training and competition - and as a potential complement to 'dissociative' focus strategies, like listening to music, for promoting exercise adherence in those who are less active. This recommendation comes with many caveats.
Whether any particular attentional focus strategy actually affects meaningful outcomes, like muscle fatigue or strength gains, remains to be determined. Moreover, most relevant study samples are small - with 11-29 participants, prototypically young, Western, male and experienced in weightlifting. Larger, more demographically diverse studies should probe the issue further.
‘It would be worthwhile to examine whether transfer of these effects occurs to similar sporting tasks’ suggested Neumann; ‘For example, some sports like shot put and discus, require a short-term maximal muscular effort. We should also explore ways to maximise the beneficial effects of an external focus. Using VR for instance, completing a deadlift could be translated into an imperative like virtually lifting a heavy bar to free a trapped virtual person.’
Regardless, there will remain a place in exercise regimens for mind-muscle connection. Off-target and ill-coordinated muscle activity notwithstanding, a focus on muscles involved in lifting still increases activation of their fibres, which is useful for hypertrophy, particularly since one cannot lift heavy all the time. It also increases awareness of form - important in beginners, who have not yet learnt correct lifting form, so are less likely to benefit from ‘automatic’ movements.
Reduced carb intake improves type 2 diabetes blood sugar regulation
Patients with type 2 diabetes improve their ability to regulate their blood sugar levels if they eat food with a reduced carbohydrate content and an increased share of protein and fat according to a recent Danish study.
Published in the journal Diabetologia, the findings of the study, conducted at Bispebjerg Hospital in collaboration with Aarhus University and the Department of Nutrition, Exercise and Sports at the University of Copenhagen, among others, are contrary to the conventional dietary recommendations for type 2 diabetics.
Patients diagnosed with type 2 diabetes are often overweight and are typically advised to follow a diet focused on weight loss: containing less calories than they burn, low fat content and a high content of carbohydrates with a low ‘glycaemic index’ (which indicates how quickly a food affects blood sugar levels).
A central aspect in the treatment of type 2 diabetes is the patient’s ability to regulate their blood sugar levels, and new research now indicates that a diet with a reduced carbohydrate content and an increased share of protein and fat improves the patient’s ability to regulate his or her blood sugar levels compared with the conventional dietary recommendations. In addition, it reduces liver fat content and also has a beneficial effect on fat metabolism in type 2 diabetics.
‘The purpose of our study was to investigate the effects of the diet without ‘interference’ from a weight loss. For that reason, the patients were asked to maintain their weight. Our study confirms the assumption that a diet with a reduced carbohydrate content can improve patients’ ability to regulate their blood sugar levels – without the patients concurrently losing weight’ explained senior consultant, DMSc Thure Krarup, MD, from the Department of Endocrinology at Bispebjerg Hospital; ‘Our findings are important, because we’ve removed weight loss from the equation. Previous studies have provided contradictory conclusions, and weight loss has complicated interpretations in a number of these studies.’
Based on the growing body of evidence, dietary recommendations for patients with type 2 diabetes may be reconsidered, stressed Krarup; ‘The study shows that by reducing the share of carbohydrates in the diet and increasing the share of protein and fat, you can both treat high blood sugar and reduce liver fat content. Further intensive research is needed in order to optimise our dietary recommendations for patients with type 2 diabetes’ he said, stressing that the findings should be confirmed in large-scale, long-term controlled trials.
Source: University of Copenhagen
Age, gender and culture influence how much sleep we get
A new study of young and middle-aged adults shows that levels of tiredness may be linked to the way society functions in different parts of the world.
Researchers from Flinders University and the University of Helsinki collaborated with Finnish company, Polar, to compare the sleeping habits of 17,335 people wearing fitness trackers to measure their 14-day sleep patterns.
As published in Sleep Medicine, they looked at sleep duration, sleep midpoint and weekend catch up for participants aged 16 to 30.
Sleep expert Professor Michael Gradisar said the study indicated differences in sleep durations shift dramatically throughout adolescence and stabilise near 30 years of age around the world.
‘Sleep duration ranged from 7:53 hours at age 16 to 7:29 hours at age 30. There were also clear differences between females and males throughout adolescence and young adulthood, with girls having longer sleep and earlier timed sleep’ said Gradisar.
‘In recent decades, there have been reports of delayed sleep in young people, characterised by very late bedtimes, and difficulties waking up in the morning at a socially-appropriate time. As sleep is a central element in functioning, health, and wellbeing, the reliable detection of sleep patterns is a key interest.’
The results also show location matters, with people in the Middle East, Asia and Southern Europe getting significantly less sleep when compared to everyone else.
‘Young adults in Asia had the shortest sleep duration (6 hours 30 minutes), whereas those in Oceania (7 hours 14 minutes) and Europe, (7 hours 7 minutes) had the longest. Young adults in Central and Southern America and the Middle East also reported short sleep (6 hours 40 minutes).
‘Higher work and educational demands in Asian countries compared to the West likely explain the later shorter sleep duration, coupled with similar catch up sleep, seen in those Asian regions. For example, when I was in Hong Kong last year speaking to colleagues, they informed me of Typhoon Mangkhut, which was one of the most destructive storms in the city’s history. The very next day, workers were ordered to go back to work by a billionaire tycoon. My colleagues spoke of walking to work, stepping over fallen trees, and broken windows and paper in the streets. This is a city that doesn’t rest – and part of a region that doesn’t sleep much.
‘So our findings suggest that cultural factors likely impinge upon the sleep opportunity of young people around the world.’
Source: Flinders University