Tag Archives: exercise

Mobility, Exercise Physiology, Strength, Weight/Fat loss

Strength Training Alters The Trajectory Of Ageing

12 Comments
Share this:

On a global scale, the number of people over 60 yr is expected to more than double from 841 million in 2012 to more than 2 billion by 2050. This change in demographics will have profound implications for many aspects of life. Furthermore, Government bodies worldwide will be faced with considerable challenges related to aging policy and how best to deal with this new reality.

Of the many things that occur during the ageing process one of the most obvious signs is the loss of skeletal muscle mass (sarcopenia) and strength (dynapenia) with decrements in physical function and potential predisposition to disability. The process whereby there is a gradual loss of muscle mass and concomintant reduction in strength and physical function with ageing – is primarily caused by a loss in number of muscle fibres and preferential loss and atrophy of fast-twitch type-IIx fibres. The loss in fibre number and atrophy and loss of type-IIx fibres may be related to a loss of innervation of muscle fibres and a progressive loss of alpha-motorneurons (see here).

I want to try and explain, therefore, why I think it is so important for anyone over 40 to spend some time in their week lifting weights – or what is more technically known as resistance training (for the short version click here). There has been a significant amount of research conducted to show that one of the very best ways to slow down this process is to perform regular and challenging resistive-based exercise or weight training. Recently, more data has emerged suggesting that an even greater benefit may be achieved with high-velocity power training (see here & here). Such training is slightly different to traditional strength training in that exercises are performed with light-to-moderate loads or weight, but movement speed is performed at fast to very fast speeds. Evidence demonstrates that such activity can even reverse some of the changes seen due to the combination of ageing and sedentariness, by specifically stimulating and increasing the strength and size of these fast twitch type-II muscle fibres (see here).

Over 25 years ago a seminal and ground-breaking research study was conducted which completely questioned our scientific understanding of what was possible when very old frail people were exposed to resistance training. In many ways the findings of this study are at the core of why most, if not all people over 40, should be doing some resistance training – colloquially speaking – “pumping iron”. Whilst weight, strength or resistance training may not be everyone’s cup of tea if there is one form of exercise that can substantially and dramatically improve functional physical capacity it is this form of exercise that promises so much.

To show that middle-aged or older adults derive huge benefits from lifting weights and strength training
Lifting weights helps keep older people young

A pivotal moment in my life occurred whilst doing PhD studies in the early 1990s. My project was to review the literature in a chosen area and my area of interest that I had developed for a while by then was resistance training. I had been introduced to this type of exercise as a means to improve athletic performance as an aspiring junior Track & Field athlete. The dramatic improvement in my performance once I had added this to my training program was extraordinary. Since that point in time I have lifted weights regularly and done countless squats, deadlifts, power cleans, tossed tractor tyres, pulled on pulley’s, performed push-ups, stood on Swiss Balls, jumped over hurdles……………………………………

I chose to focus on and study the morphological (structural) and functional changes that occur in human skeletal muscle as we age and what can be done to attenuate or slow these changes down. The simple answer to that question is to perform regular but challenging resistance training.

It was during this literature review that a very important piece of research came to my attention.

The question that had remained largely unanswered was how much of the biological “age-related” decline in muscle size, strength and function is attributable to ageing per se or to the extremely sedentary lifestyles adopted by many people as they grow older?

It is quite clear that both the ageing process and disuse syndromes (meaning no physical activity) contribute to a preferential loss of muscle fibres, specifically type-IIx fibres, and it is these muscle fibres that are involved in movements that require high amounts of force, power and speed. The critical question is, then, to what degree could intervening with a progressive resistance training program alter the trajectory of this decline in muscle strength and function and is it indeed possible to even reverse some portion of the assumed “age-related” decline seen in older people.

The study that everyone should read

The study that was published in JAMA (The Journal of the American Medical Association) June 13, 1990 by Maria Fiatarone and colleagues (see here) undertook to determine the feasibility and the physiological consequences of high-resistance strength training in the frail elderly. You are probably wondering just how frail. Well, not wanting to mince my words these participants were very frail and were probably coming to the final years or even months of their lives.

Their average age was just over 90, there were 6 women and 4 men, 60% had level 2 pattern of care (meaning they were not independent and required moderate assistance), 8 had a history of falls, 7 habitually used ambulatory assistive devices, there was over 4 chronic diseases per person and daily medications taken per person equated to more than 4. The most common medical diagnoses were osteoarthritis (7 subjects), coronary artery disease (6 subjects), osteoporotic fracture (6 subjects) and hypertension (4 subjects). Four of 10 subjects had anthropometric evidence of undernutrition and a substantial proportion did not obtain the recommended daily allowance for important micronutrients. (Click on graphs for clearer view of results)

To show the difference in cross-sectional area of skeletal muscle in older adults that are independent compared to those that require assistance
Muscle mass versus functional mobility

Muscle accounted for only 31% of the total cross-sectional area of the thigh as determined by CT scans, which meant that there was more fat and bone than muscle and it would be stating the obvious to you that this is not conducive to good balance, strength or functional mobility. Baseline muscle function was terrible with a 6 metre walk taking an average time of 22 seconds to complete with one subject taking almost 1 minute. Many struggled to raise themselves out of a chair without the assistance of their arms. Strength at the beginning of the study was positively correlated with fat-free mass (total muscle) and midthigh muscle area, whereas it was related inversely to time taken to stand from a chair and time to walk 6 metres.

What this means is that those that had more muscle tissue and greater strength at the start of the study (baseline) were able to perform better on the walk test and chair stand by executing these tasks more quickly.

Reduced physical strength and mobility with ageing affects health and wellbeing
The ageing process can be modified with exercise

Now to the interesting part of the study.

The results

Notwithstanding that there were only 10 elderly people involved, the findings were incredible and well beyond what was expected. What was even more surprising was only one simple exercise was employed: unilateral leg extension (i.e. single-leg) using a standard weight-and-pulley system. The 8-week training program used principles of progressive resistance training (in other words, as they got stronger the relative loads were increased), employed concentric and eccentric muscle contractions (whereby the muscle shortens and lengthens whilst under tension), trained 3 times/week completing 3 sets of 8 repetitions of each leg in 6-9 seconds/rep, with 1- to 2- minute rest periods between sets.

In light of their age, their general health status and the fact that they were only doing one simple exercise that primarily focused on the quadricep muscle (thigh) it would be within reason to think that the outcomes of the program would be quite negligible. However, that did not happen and this basically demonstrates that no matter how old, how injured, how dysfunctional you may be, your body and the skeletal muscle you stimulate – by performing challenging physical movement – will not only respond but it will respond quite robustly.

Exercise slows the ageing process and how weight training can increase muscle strength even the those that are 60, 70, 80 years old
Muscle strength improvement follows resistance training

Tolerance of the resistance training program was excellent with 90% completion rate (9 out of 10 finished), and no cardiovascular complications were seen. There was occasional hip and knee discomfort and that would be expected but no analgesics were required and no training sessions were missed. Gains in muscle strength were impressive and after just 8 weeks of training average strength had increased by over 170% and responsiveness to training was not different in men vs women. Some subjects made quite extraordinary gains of almost 400%. Muscle size increased in 5 of the 7 of the subjects that were CT scanned for total midthigh muscle area. Of those with stable body weight, the mean muscle area increases were significant with total midthigh muscle area going up 11.7%, the quadriceps up by 14.5% and the hamstrings/adductors by 10.6%.

Functional mobility accompanied the improvements in strength and muscle hypertrophy (growth). The time taken to complete the walking test improved substantially from 44 seconds to 29 seconds representing a 48% improvement. Two subjects no longer needed canes to walk at the end of the study and one of three subjects who could not initially rise from a chair without the use of their arms became able to do so. Importantly, no subjects experienced falls during the study. The physiological and functional improvements  were truly incredible. The effects of detraining were assessed too (stopped the program) and what this showed was that the gains made were very quickly lost with a significant 32% decrease in maximum strength after only 4 weeks of ceasing the training.

What are the major implications of these findings?

exercise physiology, exercise physiologist, Townsville Queensland Australia
Strength is fundamental to life

The results clearly demonstrated that progressive resistance training at sufficient loads (greater than 80% 1RM; i.e. lifting 80% of the maximum weight you can lift once) can induce dramatic and substantial increases in muscle strength, size and function in frail men and women up to 96 years of age. Achieving such favourable responses to strength training in these subjects is remarkable when one considers their very advanced age, extremely sedentary lifestyles, multiple chronic diseases and functional disabilities, and nutritional inadequacies. What is clear is that the preservation of fat-free mass (muscle) as one ages is a critical factor and directly affects muscle strength in the older person.

Exercise and resistance training specifically, is able to provide the neuromuscular system the appropriate physiological stimulus to reverse and modify a portion of the muscle weakness and functional loss often and simply put down to old age. Re-read that sentence because that is huge!

The final thing I would like to say on this study which deserves comment is that the results are all the more impressive because the subjects performed only one simple exercise (leg extension done unilaterally). Obviously if one employs resistance training exercises that are more complex, multi-jointed and aim to stimulate all the muscles of the upper and lower extremities (using different exercises) the structural and functional improvements would potentially be even greater.

For local Townsville residents interested in FitGreyStrong’s Exercise Physiology services or exercise programs designed to improve muscular strength, physical function (how you move around during the day) and quality of life or programs to enhance athletic performance, contact FitGreyStrong@outlook.com or phone 0499 846 955 for a confidential discussion.

For other Australian residents or oversees readers interested in our services, please see here.

Disclaimer: All contents of the FitGreyStrong website/blog are provided for information and education purposes only. Those interested in making changes to their exercise, lifestyle, dietary, supplement or medication regimens should consult a relevantly qualified and competent health care professional. Those who decide to apply or implement any of the information, advice, and/or recommendations on this website do so knowingly and at their own risk. The owner and any contributors to this site accept no responsibility or liability whatsoever for any harm caused, real or imagined, from the use or distribution of information found at FitGreyStrong. Please leave this site immediately if you, the reader, find any of these conditions not acceptable.

© FitGreyStrong

Share this:
Weight/Fat loss, Exercise Physiology, Nutrition

Regular Exercise Doesn’t Promote Weight Loss: Fact or Fiction?

3 Comments
Share this:

Several years ago researchers and authors Malhotra, Noakes & Phinney published an article in the British Journal of Sports Medicine titled:

“It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet” (see here)

This created quite a storm in several fields of scientific research including many fitness and nutrition blogs. It was lambasted by some though as inaccurate and misleading – just Google the title of the article and you’ll understand what I mean. Essentially, their article claimed that regular physical activity does not promote weight loss and that excessive consumption of carbohydrates, in particular, sugar, is the primary cause of the obesity epidemic. Whilst excessive sugar consumption has played an important role in exacerbating the obesity crisis, it would be naive and short-sighted to suggest that this is the be-all and end-all in explaining society’s current predicament.

More recently Julia Belluz and Javier Zarracina published (April 2016) an article at Vox titled:

“Why you shouldn’t exercise to lose weight, explained with 60+ studies” (see here)

This article posits that exercise is unhelpful for weight loss and makes very similar claims to the Malhotra et al. paper. Of course, the real question is, are these claims valid? Could it really be true that weight loss is not facilitated by increasing daily energy expenditure and exercise? I think the answer to these questions are not black or white. My main concern with the articles mentioned above is that they are rather myopic, polarising and do not provide a fair and balanced assessment of the current evidence.

Instead, the evidence published to date demonstrates that ‘our’ increasing waistlines are closely related – but not confined to – the interaction of the following 3 factors. Firstly, the sum total of all physical movement performed whilst awake has substantially decreased over the last 50 years. Secondly, activities of a sedentary nature have dramatically increased. What are you doing right now? Thirdly, total energy intake over the last 50 years has continued to increase over and above total daily energy expenditure requirements. If movement levels are low and energy intake high – irrespective of where the excess is derived from – body weight, body fat and BMI will naturally increase. But does increasing physical activity levels via a formalised exercise program and/or non-exercise based physical activities (e.g. leisure time movement, domestic chores/activities) facilitate weight loss by increasing total daily energy expenditure? The answer to this is yes and no.

Today I want to focus on the evidence that was accessible following a  brief Google Scholar search that supports exercise as well as other non-exercise increases in daily physical movement as being promoters of weight loss. For anybody not familiar with Google Scholar (https://scholar.google.com.au), it is a search engine by Google that searches for only published, peer-reviewed journal-based research and consequently provides information that is evidence-based rather than ‘opinion-based’ which is largely what would be accessed via Google, Yahoo or any other search engine. So, what did I find?

One of the more interesting pieces of research that directly contradicts the article by Malhotra and co. is that written by Church et al. (2011). They concluded that over the last 50 years in the U.S., daily occupation-related energy expenditure was estimated to have decreased by more than 100 calories per day, and this reduction in energy expenditure could account for a significant portion of the increase in mean U.S. body weights for women and men. What this would suggest is that rather than increased obesity rates being caused exclusively by too many carbs or too much sugar, as argued by the “you can’t outrun a bad diet” article, the current problem has been driven by large reductions in energy expenditure due to changes to occupation-related physical movement. In other words, we have transitioned from jobs that are active and require a lot of physical movement to jobs now that have most of us sitting on our backsides for hours on end.

Work places changes to physical activity
Doing this all day can’t be helpful

Previous reports based on estimated caloric consumption from food production and food disappearance (food waste) estimates have concluded that increased caloric consumption could account for most, if not all, of the weight gained at a population level in the U.S. Nonetheless, a recently validated differential equation model was used to identify a conservative lower bound for the amount of food waste in the U.S. (Hall et al. 2009). This analysis determined that prior estimates of national food waste were grossly underestimated; indicating that the national average caloric intake was much lower than previously estimated. As such, these results and those of Church imply that increased caloric intake or for that matter, increased sugar consumption, cannot solely account for the observed trends in national weight gain in the US.

The following is a summary of some of the research that has been published investigating whether obesity is related to physical inactivity and what effect increased physical activity has on obesity risk and management.

1. Banks et al. (2010) reported that: “Obesity increases with increasing screen-time, independent of purposeful physical activity.”

2. Goodpaster et al. (2010) found that: “Among patients with severe obesity, a lifestyle intervention involving diet combined with initial or delayed initiation of physical activity resulted in clinically significant weight loss and favourable changes in cardiometabolic risk factors.” In the group where physical activity was delayed, the addition of such physical activity promoted greater reductions in waist circumference and hepatic fat content.

3. Banks et al. (2011) showed that: “Domestic activities and sedentary behaviours are important in relation to obesity in Thailand, independent of exercise-related physical activity. In this setting, programs to prevent and treat obesity through increasing general physical activity need to consider overall energy expenditure and address a wide range of low-intensity high-volume activities in order to be effective.”

4. Villareal et al. (2011) demonstrated that: “…in obese older adults a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone.”

5. McGuire & Ross (2012) reported that: “…light physical activity, incidental physical activity and sedentary behaviour were not associated with abdominal obesity amongst inactive men and women whereas moderate-to-vigourous physical activity predicted lower visceral adipose tissue.”

6. The study by Fan et al. (2013) was: “…to test if moderate-to-vigorous physical activity (MVPA) in less than the recommended ≥10-minute bouts related to weight outcomes.” Both higher-intensity short bouts and long bouts of physical activity related to lower BMI and risk of overweight/obesity whereas neither lower-intensity short bouts nor long bouts related to BMI or risk of overweight/obesity. They concluded that: “The current ≥10-minute MVPA bouts guideline was based on health benefits other than weight outcomes. Our findings showed that for weight gain prevention, accumulated higher-intensity PA bouts of <10 minutes are highly beneficial, supporting the public health promotion message that ‘every minute counts’.”

7. Cleland et al. (2014) found that: “High sitting and low activity increased obesity odds among adults. Irrespective of sitting, men with low step counts had increased odds of obesity. The findings highlight the importance of engaging in physical activity and limiting sitting.”

8. Jakicic et al. (2014) concluded that moderate-to-vigorous physical activity (MVPA > 10) of 200-300 min per week, coupled with increased amounts of low-intensity physical activity (LPA), are associated with improved long-term weight loss. Interventions should promote engagement in these amounts and types of physical activity.

9. Murabito et al. (2015) discovered that moderate-to-vigorous physical activity (MVPA) as measured by accelerometry was associated with less visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and better fat quality as assessed by multi-detector computed tomography. With increasing MVPA, there was a concomitant decrease in VAT. Higher levels of MVPA were associated with higher SAT fat quality, even after adjustment for SAT volume. They concluded that:

“MVPA was associated with less VAT and SAT and better fat quality.”

10. Mekary et al (2015) reported that: “….over 12 years long-term weight training is associated with less waist circumference increase, whilst moderate-to-vigorous aerobic activity was associated with less body weight gain in healthy men.”

11. Hume et al. (2016) concluded that: “….counter to the energy surfeit model of obesity, results suggest that increasing energy expenditure may be more effective for reducing body fat than caloric restriction, which is currently the treatment of choice for obesity.”

12. Myers et al. (2016) suggests that there exists clear associations among objective measures of physical activity, sedentary behaviour, energy expenditure, adiposity and appetite control. They produced data that indicates strong links between physical inactivity and obesity with this relationship likely to be bidirectional.

13. Wu et al. (2017) tested 12-weeks of low- and high-intensity exercise training in Mexican-American and Korean premenopausal overweight/obese women. Results showed that such exercise reduced body mass index, body fat percentage, fat mass and visceral adipose tissue with concurrent increases in lean mass.

14. Quist et al. (2018) examined the effects of 6-months of active commuting and leisure-time exercise on fat loss in women and men who were overweight or obese. Clinically meaningful fat loss of over 4 kilograms was elicited. Vigorous intensity exercise was shown to be more effective in reducing body fat versus moderate intensity exercise.

15. Stoner et al. (2019) concluded that the findings of their meta-regression “lend support to the use of exercise prescription for promoting weight loss and improving health outcomes in adolescents with overweight/obesity.”

16. Zhang et al. (2020) found that 12-weeks of intense exercise (without concurrent nutritional intervention, i.e. ‘put on a diet’) significantly improved cardiometabolic parameters (i.e. fasting blood glucose) and decreased weight, total percent body fat, whole-body fat mass, android, gynoid, and trunk fat mass, abdominal subcutaneous fat and abdominal visceral fat. Reductions of over 15 cm² of abdominal visceral fat were achieved in just 3 months!

17. Berge et al. (2021) produced clinically significant weight loss in people with severe obesity despite the study having no specific focus on body weight reduction. The group that performed moderate‐intensity continuous training combined with high‐intensity interval training lost an average of 5 kilograms in 24-weeks.

Weight training, older adults and quality of life
Staying strong as we age is critical to health

What does this research tell us?

Quite a lot I would say. Of particular note is that this only represents a very small sample of the evidence that directly counters the claim that widespread societal levels of physical inactivity have little to do with burgeoning obesity rates. What is more, it crystallizes just how contentious Malhotra, Noakes & Phinney’s editorial was. Exclusively assigning blame for the obesity epidemic to the excessive intake of sugar is not supported, I believe, by the current evidence. The dramatic reductions in the sum total of all physical activity accumulated during the day appears to account for a substantial amount of the increased weight seen in recent decades.

Firstly, there is a substantial amount of research which demonstrates that sedentary behaviours, sitting time and low physical activity levels manifestly increase one’s risk of becoming overweight or obese. Secondly, moderate-to-vigourous physical activity compared to light physical activity has been shown to be associated with less visceral and subcutaneous adipose tissue, impacts positive effects on fat quality, is related to lower BMI, lowers risk of overweight/obesity, prevents weight gain following weight loss, promotes greater reductions in waist circumference and produces favourable changes in cardio-metabolic risk factors.

So to conclude, my Google Scholar search unveiled that there is a large body of evidence that demonstrates that there may be no myth to bust regarding obesity and physical inactivity or foundation to suggesting that physical activity plays no role toward promoting weight loss. Others have been critical of this line of thinking too, in particular Dr Steven Blair, so I would suggest that if you wanted to read further on this here would be a good place to start.

My next article will explore the evidence that exercise does not assist weight loss in all exercisers due to various compensatory mechanisms (see here). Until then, stay active, keep moving and don’t forget to include some resistance exercise in your week.

For local Townsville residents interested in FitGreyStrong’s Exercise Physiology services or exercise programs designed to improve health, physical function and quality of life or to enhance athletic performance, contact FitGreyStrong@outlook.com or phone 0499 846 955 for a confidential discussion.

For other Australian residents or oversees readers interested in our services, please see here.

Disclaimer: All contents of the FitGreyStrong website/blog are provided for information and education purposes only. Those interested in making changes to their exercise, lifestyle, dietary, supplement or medication regimens should consult a relevantly qualified and competent health care professional. Those who decide to apply or implement any of the information, advice, and/or recommendations on this website do so knowingly and at their own risk. The owner and any contributors to this site accept no responsibility or liability whatsoever for any harm caused, real or imagined, from the use or distribution of information found at FitGreyStrong. Please leave this site immediately if you, the reader, find any of these conditions not acceptable.
© FitGreyStrong
Share this:
Exercise Physiology, Strength, Mobility, Exercises

Why we need to look beyond just traditional strength training exercises for older adults

Leave a comment
Share this:

Exercise professionals involved with older adults pay a great deal of attention to the lower limb prime movers¹ and exercises² which will enhance the strength and power of these important muscles, and so we should. There are all sorts of ingenious ways to increase the strength, function and aesthetics of these muscles, just take a quick look at Instagram and you’ll see what I mean. The hip abductors are now recognised also, in both research and practice, as playing a pivotal role in hip and knee function influencing gait and postural stability, particularly in the medio-lateral plane. But what about the hip adductors? Are they a forgotten piece of the puzzle? Rarely do we see much attention paid to exercising these muscles of older adults in any sort of meaningful way³. This is interesting in and of itself and a curiosity, but the inference is that the adductor muscle group is not viewed as important enough to dedicate any time to specifically develop its neuromuscular capacity irrespective of some recent research that certainly suggests otherwise. There is now enough evidence to support the adductors being treated as a distinct target for improved muscle strength and power production. In fact, FGS would contend that this muscle group deserves the same degree of focus as the quads, GMax, hamstrings and hip abductors in any resistance training program for older adults given the following:

  • Age-related hip adductor strength loss appears to be more pronounced compared to the knee extensors (Daun & Kibele, 2019).

  • Postural instability with ageing is especially problematic in the medio-lateral plane (Mille et al 2013).
  • Neuromuscular rate of activation of adductors (AM) is significantly lower in older versus younger adults for both forceful static muscular contractions (IMVC) and dynamic recovery following lateral balance perturbations (Inacio et al 2019).

  • Power-based resistance training of the hip adductors (and hip abductors) has been shown to elicit improvements in maximal neuromuscular performance and enhanced medio-lateral balance recovery. Traditional (slower tempo) performed resistance training did not result in significant improvements in isolated or balance-related neuromuscular or biomechanical performance (Inacio et al 2018).

Based on the abovementioned research, FitGreyStrong’s recommendation is to ensure that weight-bearing exercises that load and challenge the adductor muscle group (frontal plane) be included in resistance training programs of older adults. Moreover, it should be acknowledged that open kinetic chain seated machines may not provide the appropriate neuromuscular challenge to bring about improvements in medio-lateral balance and function (Daun & Kibele, 2019; Inacio et al 2018) however, further research is required4.
Footnotes:
1 Quads, GMax and hamstrings
2 Squats, deadlifts, glute bridges, hip thrusts, leg curls, sit-to-stands, step-ups etc
3 The same could be said for the hip flexors where age-related muscle mass and strength losses occur disproportionately compared to other major muscle groups and this obviously impairs physical function and gait potentially increasing the risk for falls.
4 Thanks to Rhys Manchester for pointing out some inconsistencies with these concluding remarks.

For local Townsville residents interested in FitGreyStrong’s specialised Exercise Physiology services or exercise programs for older adults or for Master’s competitors wanting to enhance athletic performance, contact FitGreyStrong@outlook.com or phone 0499 846 955 for a confidential discussion.

For other Australian residents or oversees readers interested in our services, please see here.

Disclaimer: All contents of the FitGreyStrong website/blog are provided for information and education purposes only. Those interested in making changes to their exercise, lifestyle, dietary, supplement or medication regimens should consult a relevantly qualified and competent health care professional. Those who decide to apply or implement any of the information, advice, and/or recommendations on this website do so knowingly and at their own risk. The owner and any contributors to this site accept no responsibility or liability whatsoever for any harm caused, real or imagined, from the use or distribution of information found at FitGreyStrong. Please leave this site immediately if you, the reader, find any of these conditions not acceptable.

© FitGreyStrong

Share this:
Tidbits, Exercise Physiology, Strength, Nutrition

Can Vitamin D supplementation augment strength gains in older adults doing resistance training?

Leave a comment
Share this:

In a recent meta-analysis (see here), vitamin D was found to provide an additive benefit for older adults partaking in resistance training (RT). In other words, when compared to older adults taking a placebo, significantly greater gains in muscle strength were achieved in those supplemented with vitamin D. However, upon closer analysis several issues become obvious that are difficult to reconcile. The following discusses some of these issues inherent in the findings of this paper (see below).

The group 1 analysis of 3 trials finds vit D supplementation augments muscle strength of the lower limbs, SMD=0.98; see fig 2 below. (Please click on any image to open and make larger for viewing).

…but what is with the scale used for the x-axis; it seems all wrong…..all the green squares sit nicely on zero……. and where is my forest plot with 95% CI bars and my black triangle to show overall SMD?

As a crude comparison & to put this in context, Chilibeck et al (2017) found SMD=0.25 for the effect of creatine supplementation on lower body strength during RT in older adults. Perhaps the most effective supplement available? Could vit D really be that much better? 

The authors acknowledge serious inconsistency with substantial heterogeneity (see table 5) for this outcome measure and even suggest that maybe: “….these studies were unsuitable for comparison”, but conclude nonetheless that there is: “tentative support for the additive effects of RT and vit D supplementation for the improvement of muscle strength in older adults”, including those replete in Vit D.

The Uusi-Rasi et al (2015) trial was weighted heavily (75%) and rightly so being the most well designed, largest & longest RCT to date. In fact SMD of this trial in the group 1 analysis = 1.16. This is very impressive and clinically relevant if accurate and valid. Uusi-Rasi et al (2015) in contrast states: “Irrespective of vit D, exercise increased muscle strength. The predicted mean increase in lower limb extension strength was almost 15% in both exercised groups and differed significantly from the placebo without exercise group.”

“Another unexpected finding was that exercisers treated with vit D supplementation showed consistently smaller benefits than exercisers receiving placebo……our results indicate that vit D may not improve neuromuscular function, at least when vit D intake is sufficient.” The largest and longest RCT to date found no additional – and perhaps even attenuated – benefit of vit D supplementation in replete resistance-training older adults, which is at complete odds to the meta-analysis.

The Agergaard et al (2015) trial showed no additional benefit of vit D on muscle strength in older adults (vit D replete). Sample size for older adults was very small also and weighted acccordingly in the meta.

….and Bunout et al (2006) found that combined calcium/vit D supplementation was no more effective than calcium-only supplementation in older adults undergoing RT but – and this is a critical point of difference to the other 2 studies.

– all participants were arguably vit D insufficient; to be included participants had to be 16 ng/ml (40 nmol/L) or less for serum 25(OH)D. An important point that was missed by the authors of the meta-analysis (see further below).

These 3 studies included in the group 1 analysis of muscle strength of the lower limbs were identified as “all participants took part in RT and the intervention arm was supplemented with vit D (describing the additive effect of vit D supplementation when combined with RT)”

However, Bunout et al (2006) did not include a RT group that received a ‘true’ placebo. Both exercising groups in this trial received supplementation of some sort.

….one group was supplemented with vit D & calcium (intervention), the other exercising group were supplemented with calcium-only (control). “……vit D was given along with calcium in this trial, since a low calcium intake can limit the effects of the vitamin.

To isolate the effect of the vitamin, controls for supplementation received calcium also.” However results showed there were no statistically significant differences between these groups in baseline to final percentage change for right and left quadriceps strength, and right and left hand grip strength. In fact, the RT plus calcium-only group achieved better mean numerical responses in strength (non-significant) when compared to the RT plus vit D/calcium group (see table 2)……..so is it somewhat unusual that such a large SMD was found in the meta favouring the group that received vit D?

The authors state in the meta discussion that: “Interestingly, although the studies included within group 1 did not specify serum 25(OH)D levels as inclusion/exclusion critieria, baseline and postintervention serum 25(OH)D were within the ‘sufficient’ range (>30 nmol/L).”

Now there are 2 issues with this statement. Firstly, it is false that all studies included in group 1 did not specify serum 25(OH)D levels as inclusion/exclusion criteria. Bunout et al (2006) in fact did just that and specified a cut-off point for inclusion.

Subjects were screened and included only if their serum 25(OH)D levels were 16 ng/ml (40 nmol/L) or less. Secondly, mean baseline serum 25(OH)D of the vit D supplemented group in Bunout et al (2006) was 12.4 ng/ml (30 nmol/L) and many experts would propose that serum 25(OH)D of around 30 nmol/L in older adults is insufficient. It is also worth noting that Vit D status for participants of each of the 3 studies varied considerable and could possibly confound the meta.

After reviewing the 3 trials very carefully (used in the group 1 analysis of Antonia and Greig 2017), the finding that vit D supplementation significantly augments muscular strength of older adults doing RT, including those replete for vit D (SMD=0.98), is perplexing.

It is plausible and there is some evidence that vit D supplementation may augment strength of exercising older adults that have insuffient or deficient levels of vit D [serum 25(OH)D <50 nmol/L & <25 nmol/L] but such data is as yet not forthcoming in older adults performing RT

After reviewing Antoniak & Greig (2017) in which vit D supplementation significantly enhances strength in older adults doing RT, I cannot but view the findings as an artefact possibly generated by the unresolvable and substantial heterogeneity that was detected in the analysis.

The conclusion of tentative support for the ergogenity of vit D in older RT adults, irrespective of serum 25(OH)D status, is therefore premature and unsubstantiated.

For local Townsville residents interested in FitGreyStrong’s Exercise Physiology services or exercise programs designed to improve muscular strength, physical function (how you move around during the day) and quality of life or programs to enhance athletic performance, contact FitGreyStrong@outlook.com or phone 0499 846 955 for a confidential discussion.

For other Australian residents or oversees readers interested in our services, please see here.

Disclaimer: All contents of the FitGreyStrong website/blog are provided for information and education purposes only. Those interested in making changes to their exercise, lifestyle, dietary, supplement or medication regimens should consult a relevantly qualified and competent health care professional. Those who decide to apply or implement any of the information, advice, and/or recommendations on this website do so knowingly and at their own risk. The owner and any contributors to this site accept no responsibility or liability whatsoever for any harm caused, real or imagined, from the use or distribution of information found at FitGreyStrong. Please leave this site immediately if you, the reader, find any of these conditions not acceptable.
© FitGreyStrong
Share this: