The ASM index was calculated by ASM kilogram divided by height meters squared [ 30 ]. Isometric grip strength was measured in both hands using an adjustable hand grip strength dynamometer JAMAR HAND [ 32 ].

The participant was seated on a standard straight back chair without arm rests, and with elbow, hips and knees at 90° angles. All participants were instructed to squeeze the handle as hard as they could upon a verbal signal from the researcher. Verbal encouragement was provided throughout the period of effort which did not exceed 10 seconds.

Results were recorded in kilograms kg , the mean of three trials for each hand was recorded and the highest value of the two means was used for further analyses [ 32 , 33 ]. Continuous data were assessed for normality using Shapiro Wilcoxon tests and visual assessment of histograms.

Descriptive statistics were reported as means ± SD for parametric data, and frequencies and percentages for categorical data. Differences between groups were analysed using independent t-tests for parametric data, and the chi-square test of independence for categorical data.

The measurements were categorized into two groups according to sex. The measurements were further categorized according to body fat percentage into two groups. A multiple linear regression analysis was performed to determine body composition parameters predicting muscle strength in males and females.

Adjusted r, standard error values, and multicollinearity statistics were used to identify the most appropriate equations. This analysis was undertaken in males and females according to obesity classifications based on body fat percentage.

All statistical analyses were completed using the statistical software IBM SPSS version Descriptive statistics for the study population according to sex are presented in Table 1.

The mean ± SD age of participants was Males were taller, heavier and had a lower body fat percentage than females, but these differences were not significant. The mean BMI for this study population fell in the overweight BMI category Using BMI categories, In males and females, 9.

The prevalence of low muscle mass was 2. Appendicular skeletal muscle mass index and muscle strength were higher in males compared with females, this difference was significant for muscle strength only Table 1.

When exploring the association between muscle strength and muscle mass according to obesity classification using body fat percentage, muscle mass was significantly associated with muscle strength in non-obese males and females. However, in participants with obesity, muscle mass was no longer associated with muscle strength Tables 4 and 5.

In this cross-sectional study, we evaluated the relationship between muscle strength, muscle mass, and body fat percentage in older adults living in Auckland, NZ. The findings indicate that muscle strength was associated with muscle mass.

The magnitude of this association was greater in males than females, with addition of body fat percentage slightly increasing the ability of the model to predict muscle strength. When exploring the association between muscle strength and muscle mass according to obesity classification using body fat percentage, muscle mass was associated with muscle strength in non-obese participants.

However, this association was not observed in older adults who were classified as obese. This indicates that body fat percentage should be considered when measuring associations between muscle mass and muscle strength in older adults.

We found a higher prevalence of participants with obesity using body fat percentage classifications This result was as expected, as BMI has been shown to underestimate adiposity in older adults [ 37 ]. A recent survey in New Zealand using BMI classifications reported that the prevalence of obesity in older adults between 65—74 years was The lower level of obesity reported in our population may reflect our recruitment inadvertently targeting healthy older adults.

We also identified 3. The lack of studies reporting the prevalence of low muscle strength and the application of different cut-off values makes it difficult to compare studies.

In this cohort, we applied the updated cut off values of low muscle strength defined by the European Working Group on Sarcopenia in Older People EWGSOP2.

A nationally representative sample of Brazilians aged 65 years and older using the same cut-off values as our study observed a higher prevalence of low muscle strength Other studies which applied the older cut off values defined by the European Working Group on Sarcopenia in Older People EWGSOP , observed a higher prevalence of low muscle strength of The higher prevalence observed in these groups, is possibly explained by the inclusion of people older than 74 years, and a potentially less healthy population than those participants included in our study.

The prevalence of low ASMI was 6. The higher percentage in the study appears to be explained by the inclusion of adults over the ages of 74 years.

Our results provide evidence that muscle mass is positively associated with muscle strength in older men and women. This result aligns with the literature [ 43 , 44 ] and suggests that efforts to maintain muscle mass should have a significant effect on preserving strength in older adults.

When stratified by sex, we observed strong evidence that muscle mass was significantly associated, but not a major contributor to muscle strength in older men and women.

In a regression model taking into account muscle mass, it was shown that an increase of 1 unit muscle mass will increase the value of muscle strength by 0.

These results highlight not only the importance of increasing muscle mass, but also the importance of decreasing body fat percentage to preserve muscle strength in older adults. The cross-sectional nature of our data impedes any causal inference.

Nevertheless, the results from our study provide justification for further prospective research that evaluates the effects of interventions, which are aimed at optimising body composition and muscle strength in older adults.

To our knowledge, this is the first study to investigate the role of obesity classification based on body fat percentage in the relationship between muscle strength and muscle mass. Results from multiple linear regression analyses provide evidence supporting the important role of obesity classification according to body fat percentage when investigating the relationship between muscle strength and muscle mass.

Our study demonstrated that when obesity was classified using body fat percentage, muscle mass was significantly associated with muscle strength in non-obese older adults. However, an association between muscle strength and muscle mass was not observed in older adults categorised as obese.

The accumulation of intramuscular lipid content or poor muscle quality , which is seen in people with obesity may explain the influence of obesity in the relationship between muscle strength and muscle mass. Goodpaster et al. reported that higher intramuscular lipid content is associated with lower muscle strength, independent of muscle mass [ 45 ].

Also, accumulation of intramuscular lipid content is known to be associated with insulin insensitivity, inflammation and functional deficits in skeletal muscle. It will be important in the future to continue to focus on understanding predictors of muscle strength in older adults with obesity in order to provide appropriate interventions to increase muscle strength.

There were significant strengths to our study. The relatively large sample size permits us to examine whether the relationship between muscle strength and muscle mass was similar in males and females. Also, it is possible that the inclusion of community-dwelling healthy older adults provides the opportunity to identify issues and promote preventative action in early old age.

Furthermore, the use of DXA is an accurate measure of body composition. However, in contrast to magnetic resonance imaging MRI or computed tomography CT DXA cannot detect intramuscular fat from muscle mass nor distinguish the composition of muscle [ 46 , 47 ]. This cross-sectional study limits the ability to detect causality; hence, only associations were discussed.

Other limitations are the population group, which was not representative of the New Zealand population, as this cohort was composed of a convenience volunteer sample of men and women aged 65—74 years living in the community.

The classification by body fat percentage for obesity may also be perceived as a limitation given the arbitrary nature of the cut-off points. Finally, we did not assess lower extremity muscle strength, which is a more direct predictor of falls.

However, grip strength is associated with lower-body muscle strength [ 48 ] and a strong predictor of disability [ 49 ].

Muscle mass and body fat percentage were predictors of muscle strength in this cohort. Muscle mass was associated with muscle strength in non-obese older adults whereas, there was no association between muscle mass and muscle strength in older adults who were classified as obese.

This indicates that obesity classification plays an important role in the relationship between muscle strength and muscle mass in older adults.

We suggest that this could be mainly attributed to muscle quality, which could be a contributor of muscle strength in older adults who are obese. Further research should focus on identifying predictors of muscle strength in older adults with obesity.

We thank the REACH team including Cassie Slade for managing the recruitment of participants and data collection; and Karen Mumme, Harriet Guy, Angela Yu, and Nicola Gillies for assistance with data collection and data entry.

Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Article Authors Metrics Comments Media Coverage Reader Comments Figures. Abstract Background Aging is associated with decreases in muscle strength and simultaneous changes in body composition, including decreases in muscle mass, muscle quality and increases in adiposity.

Conclusions Body fat percentage should be considered when measuring associations between muscle mass and muscle strength in older adults. Introduction Globally and in New Zealand the proportion of older adults is increasing [ 1 ].

Materials and methods 2. Study design This study was a secondary aim of the Researching Eating, Activity and Cognitive Health REACH Study.

Study participants and procedures Participants included men and women aged 65—74 years, living independently in Auckland, NZ.

Data collection All participants visited the Human Nutrition Research Unit on one occasion for collection of data as part of the wider REACH study. Statistical analysis Continuous data were assessed for normality using Shapiro Wilcoxon tests and visual assessment of histograms.

Download: PPT. Table 1. Characteristics of study participants by sex a , b. Fig 1. Table 2. Results of multiple linear regression modelling on the relationship between muscle strength, mass and body fat percentage in older females.

Table 3. Results of multiple linear regression modelling on the relationship between muscle strength, mass and body fat percentage in older males.

Table 4. Results of multiple linear regression modelling on the effect of obesity in the relationship between muscle strength and mass in older females.

Table 5. Results of multiple linear regression modelling on the effect of obesity in the relationship between muscle strength and mass in older males.

Discussion In this cross-sectional study, we evaluated the relationship between muscle strength, muscle mass, and body fat percentage in older adults living in Auckland, NZ. If you become fatigued or out of breath quickly, decrease the intensity or duration of your exercise and build up from there.

Any increase in cardio exercise is beneficial, so make realistic goals that work best for you. Cardiovascular endurance, or cardio, is important for strengthening your heart and lungs, which help to deliver oxygen and nutrients throughout your body.

Muscular strength is the ability of a muscle group to exert force or lift and carry weight. The stronger your muscles, the heavier weight you can lift and move Muscular strength can vary between different muscle groups.

For example, you may have strong glutes and quads but weaker biceps. To measure your muscular strength, you can test your one-rep max, which is the maximum weight you can lift for one rep.

Progressive overload — defined as gradually increasing weight, volume, training frequency, or intensity over time — is another great way to measure your progress In addition to building strength, you may want to aim for muscle hypertrophy, or building muscle mass.

To do so, aim for 8—12 reps per set. If you want to increase your one-rep max, focus on your maximal muscular strength. You can do so by incorporating exercises with heavy weights and low reps — usually 2—6.

Make sure you practice proper form to reduce the risk of injury 10 , Being physically strong helps you move and lift heavier objects with ease, which can make day-to-day tasks much easier.

Unlike muscular strength, which measures how much weight you can lift or move, muscular endurance tests how long your muscles can withstand an exercise In addition to training for muscular strength, make sure you add some muscular endurance activities into your routine, such as:.

For example, pilates, yoga, stair climbing, and long-distance activities are good options. Muscular endurance is how long your muscles can endure an exercise. Flexibility is defined as the range of motion of a joint or group of joints without pain or difficulty 1.

Being flexible is important for daily living. For instance, it can make it easier to maintain good balance, reach the top shelf of a cupboard, or bend down to pick up something from the ground. Further, some activities require more flexibility than others, such as gymnastics, dance, and martial arts.

Though there is debate on its benefits in reducing pain and injury risk, stretching can increase your flexibility and may enhance your performance in activities that require you to be more flexible 13 , When stretching, the goal is to be gentle and limit the risk of injury. Avoid stretching your muscles to the point of extreme discomfort or pain.

Aim to do stretching activities at least 2—3 days per week. While helpful for flexibility, it may increase the risk of injury prior to activities that rely on joint support, such as weight training or high intensity sports.

Therefore, this type of stretching is generally best reserved for the cool-down phase of a workout. This is usually done during a warm-up or can be done by itself like during a stretching break at work. These include exercises that elongate and stretch the muscle during movements, such as when performing pilates, yoga, tai chi, and barre.

The purpose of dynamic movement is to wake up the muscles needed for the upcoming exercise. Endurance exercises that benefit from dynamic movement include biking, running, and swimming, as well as sports activities like basketball, soccer, and volleyball.

Regular stretching can help increase flexibility and may support your performance in sports that require flexibility.

Being flexible may help you perform daily tasks easier and maintain better balance, though more research is needed. Body composition is the last health-related component of fitness. It describes the ratio of fat mass to fat-free mass 2. Body fat is essential to human health. However, having too much — especially around the stomach area — has been linked to poorer health and a greater risk of chronic diseases like heart disease, type 2 diabetes, and certain types of cancer 15 , Meanwhile, having greater muscle and bone mass is linked with improved health outcomes and a lower risk of chronic diseases Keep in mind that health looks different for everyone.

The below parameters can help you understand your body composition 18 , 19 , 20 , 21 :. Please note that we are unable to provide general health information or advice about symptoms by email. For general health information or symptom advice, please call us at any time of the day or night.

For questions about food and nutrition, please click on Email a HealthLinkBC Dietitian. There are many ways you can add physical activity to your healthy lifestyle, no matter your age or activity level. Ask us your physical activity question. If you have questions about physical activity or exercise, call or for the deaf and hard of hearing toll-free in B.

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Iron-Fortified Infant Cereal Recipes: Finger Foods For Babies and Toddlers Making Family Meals Enjoyable Mealtime and Your Toddler Parenting Babies months Recipes for Your Baby 6 - 9 Months Old Recipes for Your Baby 9 - 12 Months Old Reducing Risk of Food Allergy in Your Baby Snack Ideas for Preschoolers Specialized Formula Shortage Vitamins and Minerals for Toddlers Your Toddler: Nutritious Meals for Picky Eaters.

Activities for School Age Children Physical Activity Tips for Children Keeping Children and Teens Active Physical Activity for Youth Fitting in Physical Activity at College or University Preventing Injuries Physical Activity in Children: Get Children Involved.

Older Adults and Endurance Fitness Resistance Training Preventing Falls: Exercises for Strength and Balance Getting Older and Staying Physically Active Aging Well Videos Physical Activity Older Adults and Flexibility Preventing Falls.

Black Cohosh for Menopause Symptoms. Health Benefits of Physical Activity Physical Activity Healthy Lifestyle Actions to Reduce and Manage Stress Mental and Emotional Benefits of Activity Muscular Strength and Endurance Physical Activity Definitions Healthy Muscles Weight-Bearing Excercises to Maintain Healthy Bones Fitness: Increasing Core Stability.

Getting Started: Adding More Physical Activity to Your Life Quick Tips: Fitting Physical Activity Into Your Day Quick Tips: Getting Active as a Family Fitness: Adding More Activity To Your Life Getting Started With Flexibility and Exercise Fitness Machines Fitness Clothing and Gear Be Active: Move to Feel Good The Three Kinds of Fitness Set SMART Goals.

What's Stopping You? Stages of Changing Behaviour Fitness: Getting Around Barriers to Exercise Overcoming Barriers to Being Physically Active for the Older Adult Physical Activity While Living with a Disability Kris's Story: Getting Active With No Excuses. How to Choose Safe Equipment Exercising While Sitting Down Fitness DVDs and Videos Tips for Picking the Right Activities Quick Tips: Getting in Shape Without Spending Money Fitness: Walking for Wellness Walk Your Way To Health Tai Chi and Qi Gong Water Exercise Yoga Bob's Story: Biking for Health Exercise and Physical Activity Ideas Fitness: Choosing Activities That Are Right for You.

Fitness: Getting and Staying Active Fitness: Making It a Habit Quick Tips: Having Enough Energy to Stay Active Quick Tips: Staying Active at Home Quick Tips: Staying Active When You Travel Physical Activity in Winter Quick Tips: Staying Active in Cold Weather Quick Tips: Staying Active in Hot Weather.

Cooling Down How to Exercise Safely Injury Prevention Flexibility Precautions for Flexibility Activities Precautions for Strengthening Activities Warming Up Warming Up and Cooling Down Overtraining Returning to Play After a Head Injury During a Sporting Event Sports-Related Dehydration.

Diabetes and Hypoglycemia Eating Disorders Healthy Eating for Disease Prevention Eating Right When You Have More Than One Health Problem Being Active When You Have More Than One Health Problem Physical Activity and Disease Prevention Anemia Anemia of Chronic Disease ACD Folic Acid Deficiency Anemia Iron Deficiency Anemia Vitamin B12 Deficiency Anemia.

Eating Guidelines for Gout Exercise and Osteoarthritis Exercise for Rheumatoid Arthritis Healthy Habits to Prevent or Reduce Problems from Osteoporosis Osteoarthritis: Excercising with Arthritis Physiotherapy for Knee Arthritis Quick Tips: Exercising Safely with Arthritis.

Excercises After Mastectomy Breast Cancer: Healthy Eating After a Diagnosis Eating Guidelines For After a Cancer Diagnosis Healthy Eating Guidelines for Cancer Survivors Cancer and Physical Activity Eating Well During Cancer Treatment Cancer Prevention Eating Guidelines.

Managing Constipation in Adults Healthy Eating Guidelines for People with Diverticular Disease Fibre and Your Health Lower Fibre Food Choices Eating Guidelines For Gallbladder Disease Healthy Eating Guidelines for Irritable Bowel Syndrome Lactose Intolerance Healthy Eating Guidelines for People with Peptic Ulcers Bowel Disease: Changing Your Diet Celiac Disease: Eating a Gluten-Free Diet GERD: Controlling Heartburn by Changing Your Habits Irritable Bowel Syndrome: Controlling Symptoms with Diet.

Severe Allergic Reaction to Food: Children and Teens Food Allergies.

Assessing body fat can be done using the following methodologies: Hydrostatic weighing, skinfold assessment and bio-electrical impedance. Of these methods, one that is both accurate and practical is skinfold measurement.

The measurements are taken with calipers, which gauge the skinfold thickness in millimeters of areas where fat typically accumulates i. Once the measurements are recorded, the numbers are inserted into an equation that calculates a body fat percentage and alternatively body lean mass.

Skinfold is a preferred method of body fat measurement for non-clinical settings because it is easy to administer with proven accuracy and is not obtrusive with regards to the patient.

It also provides much more data than just the final composition measurement - it also yields the thickness of many sites, which can be used as bases of comparison with future results. For example, an abdominal skinfold improvement from 35mm to 24mm would show a significant improvement in that site even if the overall body fat percentage may have only reduced minimally.

BMI is often mistaken as measurable guide to body fat. However, BMI is simply a weight to height ratio. It is a tool for indicating weight status in adults and general health in large populations.

BMI correlates mildly with body fat but when used in conjunction with a body fat measurement gives a very accurate presentation of your current weight status.

With that being said, an elevated BMI above 30 significantly increases your risk of developing long-term and disabling conditions such as hypertension, diabetes mellitus, gallstones, stroke, osteoarthritis, and some forms of cancer. For adults over 20 years old, BMI typically falls into one of the above categories see table above.

UC Davis Health School of Medicine Betty Irene Moore School of Nursing News Careers Giving. menu icon Menu. Sports Medicine. Prior to participation, written informed consent was obtained.

Participants were invited to participate in a 2-day cross-sectional study. Participants that expressed their interest by responding to the advertisement and were found eligible based on the medical screening questionnaire; see Additional files 1 and 3 were invited to visit the university on 2 days, with an 8—day interval.

For day 1 that always started between 8 and 8. Subsequently, participants were asked to eat a light breakfast such as one slice of bread with cheese. During the familiarization session, proper lifting techniques were demonstrated for leg press and chest press exercises by a trained instructor.

After completion of both days, participants received a gift voucher and travel expenses. Participants from the Faculty of Psychology and Neuroscience at Maastricht University were able to choose between the gift vouchers, or participation credits part of the psychology bachelor curriculum see also Fig.

Anthropometric measurements, body mass, and height were taken in the morning after an overnight fast on day 1 of testing.

Body mass was measured on an electronic scale to the nearest 0. Height was measured to the nearest 0. Body composition was calculated based on underwater weighing with simultaneous measurement of residual lung volume using the helium dilution technique Volugraph , Mijnhardt.

For this measurement, participants are in a fasted state and are completely submerged under water, for approximately 90 s to measure their weight under water, while breathing oxygen through a mouthpiece.

The measurement was repeated three times. Body density was derived from body weight and body volume, which was used to calculate fat mass and fat-free mass by the Siri equation [ 11 ].

Cardiovascular fitness was assessed with an incremental test on a bicycle ergometer using the protocol of Kuipers et al. During this test on day 1, oxygen consumption VO 2 and CO 2 production were measured continuously Omnical, Maastricht University and heart rate was monitored using a polar heart rate monitor RS, Polar Electro, Kempele, Finland; watch worn by the instructor.

After a warming up of 5 min at watts W for men and 75 W for women, the workload increases with 50 W every 2. Approximately 1 h after VO 2 max testing on day 1, participants performed a familiarization session with the exercise equipment to estimate 1RM strength.

During the familiarization session, proper lifting technique was demonstrated for leg press and chest press exercises. Guided-motion exercise machines one for leg press, one for chest press were used to establish safe and proper lifting.

Maximum strength was estimated in all participants using the multiple-repetition testing procedure [ 13 ]. In a separate session 8—10 days later; day 2 , the actual 1RM testing took place. After warming up 5 min on light load on cycle ergometer , two sets of 12 repetitions were performed on the exercise machines at a light load 15 and 25 kg on the chest press and 70 and 80 kg on the leg press, for female and male participants, respectively.

Thereafter, the load was increased by 2. On day 2, standardized exercise protocols were carried out before each questionnaire i. The strength protocol was based on the two different 1RM tests for leg press and chest press.

After a 5-min warmup 75 W; bicycle ergo meter—to minimize the chance for injuries , participants were asked to do three sets of 8—10 repetitions on the chest press apparatus and three sets of 8—10 repetitions on the leg press apparatus.

Between each set, there was a 2-min break. Between the leg press and the chest press, there was a 5-min transition time break. Also, the order of the chest press and leg press was randomized to control for a possible order effect. The aerobic exercise protocol conducted on day 2 was based on maximal heart rate and maximal workload measured during the VO 2 max test conducted on day 1, and included both cycling and running.

The running was introduced to also have two different aerobic exercises. Between the three sets of running, participants walked for 1 min. Between the cycling and running, there was a 5-min transition time break. The order of the cycling and running was counterbalanced as well.

Participants completed a questionnaire, based on the reasoned action approach [ 15 ] and the self-determination theory [ 16 ].

This questionnaire included specific and general questions about resistance and aerobic exercises and was divided accordingly into two sections for completion i. Filling out the questionnaires took about 3—5 min per stage.

The measured constructs are as follows: 1 instrumental attitudes cognitive feelings about exercises , 2 experiential attitudes affective feelings about the exercises , 3 intentions whether the participant intends to do the specific exercise in the near future , 4 intrinsic motivation how fun the exercise is , and 5 a-motivation no motivation to do the specific exercise at all.

All items were rated on a 7-point Likert scale. IBM SPSS statistics and Excel were used to analyze the data see also Additional file 2.

Frequencies n , means M , and standard deviations SD were calculated to provide an overall picture of the sample. Paired sample t -tests were conducted to calculate differences between male and female participants.

We tested the direct and indirect associations linking BMI scores with psychological constructs regarding strength exercises using the PROCESS software including the bootstrapping method with bias-corrected confidence estimates see also Fig.

Bootstrapping, a non-parametric sampling procedure, was used to assess the significance of indirect effects. Based on the z score of this difference, p values were estimated [ 19 ]. A total of 68 participants participated in this study BMI ranged from 18 to Female participants had a higher fat mass compared to male participants see Table 2.

Weight and BMI were also highly correlated with the fat-free mass and fat-free mass indices, respectively r values ranging from.

Correlational analyses. a Correlations between weight and fat mass and between weight and fat-free mass for male and female participants, separately. b Correlations between BMI and fat mass index and between BMI and fat-free mass index for male and female participants, separately.

c Correlations between fat-free mass and strength measures for male and female participants, separately. There was no direct effect of BMI on attitudes, intention, or motivations p values range from.

Indirect effects of BMI on all psychological outcomes were found via fat-free mass and the combined strength score. No indirect effect from BMI to psychological outcomes was found via strength only. Model for testing the indirect relations of BMI with psychological outcomes.

There was neither an direct effect of BMI on psychological outcomes nor an indirect effect of BMI on psychological outcomes via strength. Limited indirect effects of BMI on psychological outcomes were found via fat-free mass.

Significant effects of BMI on psychological outcomes were found when fat-free mass and strength were added to the model. To examine whether heavier people are relatively better in strength exercises than aerobic exercises compared to normal-weight people, correlations between BMI and strength outcomes and BMI and aerobic outcomes were calculated.

For the variables instrumental attitude, experiential attitude, and intention, the directions of the relations were the same, but these variables were not significant p values ranged from. We 1 confirmed that heavier people have a higher fat-free mass compared to normal-weight people.

This is in line with biological insights [ 7 ]. Additionally, 2 we have shown that people with a higher fat-free mass are stronger in absolute sense and are better in strength exercises than in aerobic exercises.

We have also confirmed that 3 mastery experiences in this case, resulting from successfully engaging in strength exercises as opposed to aerobic exercises are related to more positive psychological outcomes.

This observation is in line with psychological insights [ 20 , 21 , 22 , 23 ]. As hypothesized, we 4 have shown that heavier people are more positive about strength exercises compared to normal-weight people, via fat-free mass and muscle strength.

Moreover, 5 heavier people are better in strength exercises and are more positive about strength exercises compared to aerobic exercises. To the best of our knowledge, this is the first time that this chain of relationships has been demonstrated empirically, thereby bridging the gap between biological and psychological insights.

In light of these results, new exercise interventions for people with overweight or obesity could be developed, concentrating on biological strengths and using psychological principles and techniques to make them more aware of their strengths [ 6 ]. Additionally, for long-term behavior and health changes, new interventions might benefit from focusing and giving feedback; [ 24 ] on body composition instead of weight.

There are some limitations that should nuance the drawn conclusions. Most of the study participants are university students who volunteered to participate which might limit the generalizability of our study results.

The self-reported physical activity level was higher than year-old parents 2. The sample size is relatively small, but the used measures were accurate.

The BMI range was limited, making more research necessary among a broader BMI range. Cross-sectional data instead of longitudinal data was gathered. With that, we were not able to show causality. Two additional questions might be 1 whether the exercise protocols adequately encompass what strength and aerobic exercises are and 2 whether the possibly different training loads of the two different exercises might have influenced the results.

To ensure that we actually worked with strength and aerobic exercises, we used exercises that are generally used in our gold standard maximal strength tests and aerobic tests the additional running is also used very often in VO 2 max tests; see, e. In future research, it might be helpful to add an effort perception scale to measure the perceived intensity of the protocols.

However, most of our results were significant and in the right direction. However, an increased weight or BMI is not a very reliable tool to evaluate body composition and, with that, individual metabolic health [ 27 ]. In conclusion, a benefit of being overweight is being strong. Strength exercise interventions might have the ability to make people who are overweight more motivated to be physically active on the long term.

In short, strength exercises might contribute to the management of obesity. With interventions focusing on strength exercises, the obesity problem per se will not be solved, but such programs might positively contribute to obesity-related health issues.

Alberga AS, Farnesi BC, Lafleche A, Legault L, Komorowski J. The effects of resistance exercise training on body composition and strength in obese prepubertal children.

Physician and Sports Medicine. Article Google Scholar. Swinburn BA, Sacks G, Hall KD, McPherson K, Finegood DT, Moodie ML, Gortmaker SL. The global obesity pandemic: shaped by global drivers and local environments. Article PubMed Google Scholar. Heath GW, Parra DC, Sarmiento OL, Andersen LB, Owen N, Goenka S, et al.

Evidence-based intervention in physical activity: lessons from around the world. Article PubMed PubMed Central Google Scholar.

Ten Hoor GA, Plasqui G, Schols AMWJ, Kok G. Combating adolescent obesity: an integrated physiological and psychological perspective. Current Opinion in Clinical Nutrition and Metabolic Care. Ten Hoor GA, Plasqui G, Ruiter RAC, Kremers SPJ, Rutten GM, Schols AMWJ, et al.

A new direction in psychology and health: resistance exercise training for obese children and adolescents. The findings indicate that muscle strength was associated with muscle mass.

The magnitude of this association was greater in males than females, with addition of body fat percentage slightly increasing the ability of the model to predict muscle strength. When exploring the association between muscle strength and muscle mass according to obesity classification using body fat percentage, muscle mass was associated with muscle strength in non-obese participants.

However, this association was not observed in older adults who were classified as obese. This indicates that body fat percentage should be considered when measuring associations between muscle mass and muscle strength in older adults.

We found a higher prevalence of participants with obesity using body fat percentage classifications This result was as expected, as BMI has been shown to underestimate adiposity in older adults [ 37 ].

A recent survey in New Zealand using BMI classifications reported that the prevalence of obesity in older adults between 65—74 years was The lower level of obesity reported in our population may reflect our recruitment inadvertently targeting healthy older adults. We also identified 3.

The lack of studies reporting the prevalence of low muscle strength and the application of different cut-off values makes it difficult to compare studies.

In this cohort, we applied the updated cut off values of low muscle strength defined by the European Working Group on Sarcopenia in Older People EWGSOP2. A nationally representative sample of Brazilians aged 65 years and older using the same cut-off values as our study observed a higher prevalence of low muscle strength Other studies which applied the older cut off values defined by the European Working Group on Sarcopenia in Older People EWGSOP , observed a higher prevalence of low muscle strength of The higher prevalence observed in these groups, is possibly explained by the inclusion of people older than 74 years, and a potentially less healthy population than those participants included in our study.

The prevalence of low ASMI was 6. The higher percentage in the study appears to be explained by the inclusion of adults over the ages of 74 years. Our results provide evidence that muscle mass is positively associated with muscle strength in older men and women.

This result aligns with the literature [ 43 , 44 ] and suggests that efforts to maintain muscle mass should have a significant effect on preserving strength in older adults.

When stratified by sex, we observed strong evidence that muscle mass was significantly associated, but not a major contributor to muscle strength in older men and women. In a regression model taking into account muscle mass, it was shown that an increase of 1 unit muscle mass will increase the value of muscle strength by 0.

These results highlight not only the importance of increasing muscle mass, but also the importance of decreasing body fat percentage to preserve muscle strength in older adults. The cross-sectional nature of our data impedes any causal inference. Nevertheless, the results from our study provide justification for further prospective research that evaluates the effects of interventions, which are aimed at optimising body composition and muscle strength in older adults.

To our knowledge, this is the first study to investigate the role of obesity classification based on body fat percentage in the relationship between muscle strength and muscle mass.

Results from multiple linear regression analyses provide evidence supporting the important role of obesity classification according to body fat percentage when investigating the relationship between muscle strength and muscle mass.

Our study demonstrated that when obesity was classified using body fat percentage, muscle mass was significantly associated with muscle strength in non-obese older adults.

However, an association between muscle strength and muscle mass was not observed in older adults categorised as obese. The accumulation of intramuscular lipid content or poor muscle quality , which is seen in people with obesity may explain the influence of obesity in the relationship between muscle strength and muscle mass.

Goodpaster et al. reported that higher intramuscular lipid content is associated with lower muscle strength, independent of muscle mass [ 45 ]. Also, accumulation of intramuscular lipid content is known to be associated with insulin insensitivity, inflammation and functional deficits in skeletal muscle.

It will be important in the future to continue to focus on understanding predictors of muscle strength in older adults with obesity in order to provide appropriate interventions to increase muscle strength.

There were significant strengths to our study. The relatively large sample size permits us to examine whether the relationship between muscle strength and muscle mass was similar in males and females.

Also, it is possible that the inclusion of community-dwelling healthy older adults provides the opportunity to identify issues and promote preventative action in early old age.

Furthermore, the use of DXA is an accurate measure of body composition. However, in contrast to magnetic resonance imaging MRI or computed tomography CT DXA cannot detect intramuscular fat from muscle mass nor distinguish the composition of muscle [ 46 , 47 ].

This cross-sectional study limits the ability to detect causality; hence, only associations were discussed. Other limitations are the population group, which was not representative of the New Zealand population, as this cohort was composed of a convenience volunteer sample of men and women aged 65—74 years living in the community.

The classification by body fat percentage for obesity may also be perceived as a limitation given the arbitrary nature of the cut-off points.

Finally, we did not assess lower extremity muscle strength, which is a more direct predictor of falls.

However, grip strength is associated with lower-body muscle strength [ 48 ] and a strong predictor of disability [ 49 ]. Muscle mass and body fat percentage were predictors of muscle strength in this cohort. Muscle mass was associated with muscle strength in non-obese older adults whereas, there was no association between muscle mass and muscle strength in older adults who were classified as obese.

This indicates that obesity classification plays an important role in the relationship between muscle strength and muscle mass in older adults. We suggest that this could be mainly attributed to muscle quality, which could be a contributor of muscle strength in older adults who are obese.

Further research should focus on identifying predictors of muscle strength in older adults with obesity. We thank the REACH team including Cassie Slade for managing the recruitment of participants and data collection; and Karen Mumme, Harriet Guy, Angela Yu, and Nicola Gillies for assistance with data collection and data entry.

Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Article Authors Metrics Comments Media Coverage Reader Comments Figures. Abstract Background Aging is associated with decreases in muscle strength and simultaneous changes in body composition, including decreases in muscle mass, muscle quality and increases in adiposity.

Conclusions Body fat percentage should be considered when measuring associations between muscle mass and muscle strength in older adults. Introduction Globally and in New Zealand the proportion of older adults is increasing [ 1 ].

Materials and methods 2. Study design This study was a secondary aim of the Researching Eating, Activity and Cognitive Health REACH Study.

Study participants and procedures Participants included men and women aged 65—74 years, living independently in Auckland, NZ. Data collection All participants visited the Human Nutrition Research Unit on one occasion for collection of data as part of the wider REACH study.

Statistical analysis Continuous data were assessed for normality using Shapiro Wilcoxon tests and visual assessment of histograms.

Download: PPT. Table 1. Characteristics of study participants by sex a , b. Fig 1. Table 2. Results of multiple linear regression modelling on the relationship between muscle strength, mass and body fat percentage in older females.

Table 3. Results of multiple linear regression modelling on the relationship between muscle strength, mass and body fat percentage in older males. Table 4. Results of multiple linear regression modelling on the effect of obesity in the relationship between muscle strength and mass in older females.

Table 5. Results of multiple linear regression modelling on the effect of obesity in the relationship between muscle strength and mass in older males. Discussion In this cross-sectional study, we evaluated the relationship between muscle strength, muscle mass, and body fat percentage in older adults living in Auckland, NZ.

Prevalence of obesity, low muscle strength and low muscle mass We found a higher prevalence of participants with obesity using body fat percentage classifications Association between body composition and muscle strength Our results provide evidence that muscle mass is positively associated with muscle strength in older men and women.

The role of obesity classification in the relationship between muscle strength and muscle mass To our knowledge, this is the first study to investigate the role of obesity classification based on body fat percentage in the relationship between muscle strength and muscle mass. Conclusions Muscle mass and body fat percentage were predictors of muscle strength in this cohort.

Supporting information. S1 File. s SAV. Acknowledgments We thank the REACH team including Cassie Slade for managing the recruitment of participants and data collection; and Karen Mumme, Harriet Guy, Angela Yu, and Nicola Gillies for assistance with data collection and data entry.

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Results of two population-based studies. Arch Intern Med. Rubenstein LZ, Josephson KR. The epidemiology of falls and syncope. Clin Geriatr Med.