Aging, long-distance running, and the development of musculoskeletal disability. A controlled study

Spatiotemporal and kinematic adjustments in master runners may be associated with the relative physiological effort during running

Master runners maintain a similar running economy to young runners, despite displaying biomechanical characteristics that are associated with a worse running economy. This apparent paradox may be explained by a greater physiological effort-i.e., percentage of maximal oxygen uptake (VO2-max)-that master runners perform at a given speed. Moreover, age-related responses to non-exhaustive sustained running are yet underexplored. The aims of this study were, therefore, to examine if biomechanical adjustments in master runners are physiological-effort dependent, and to explore the age-related biomechanical changes during a non-exhaustive sustained run. Young (23.9 ± 6; n = 12) and master (47.3 ± 6.9; n = 12) runners performed a sustained 30-minute treadmill run matched for relative physiological effort (70% VO2-max), while spatiotemporal and lower-limb kinematic characteristics were collected during the 1st and 30th minute. Group differences were observed in step/stride length, knee touch-down angle, and knee stiffness. However, both groups of runners had a similar step frequency, vertical center of mass oscillation, and knee range of motion. Age-related adjustment in these latter characteristics may thus not be an inevitable result of the aging process but rather a strategy to maintain running economy. The relative physiological effort of runners should, therefore, be considered when examining age-related adjustments in running biomechanics.

What Do We Know About the Value of Sport for Older Adults? A Scoping Review

Issues relating to older adults in sport are ongoing topics of interest among sport scientists; however, our knowledge on how older athletes have been studied is incomplete, which has implications for understanding the comprehensiveness of this evidence base. This scoping review aimed to provide an overview of how sport and older adults have been studied since the first World Masters Games. Data on research topics, research methods, sport-specific information, and demographic information on older athletes were collected and reviewed. Results suggest older athletes who are White, male, and competitive athletes have largely been the focus of research. In addition, results highlight an alarming number of unreported data related to the demographics of athlete samples. As a result, the well-documented benefits of sport may reflect a homogenous group of older adults, limiting our overall understanding of aging and sport and the value of this research for developing evidence-informed policy.

Age and training volume influence joint kinetics during running

Recently, we proposed the hypothesis that weekly running volume and preferred running pace may play a role in preserving ankle joint kinetics in middle-age runners as ankle joint kinetics were generally similar in young and middle-aged runners with similar running volume and preferred pace. To further address this hypothesis, we compared lower extremity joint kinetics between high and low training volume runners in both young and middle-aged groups. Joint kinetics calculated from 3D kinematic and ground reaction force data during over-ground running at 2.7 m·s^-1 from young and middle-aged runners who ran low or high weekly volume were analyzed. A two-factor analysis of variance was used to compare joint kinetics between age and running volume groups. Positive hip work was greater in middle-aged compared to young runners (P = .005). Plantarflexor torque (P = .009) and positive ankle work (P = .042) were greater in young compared to middle-aged runners. Positive ankle work was also greater in the high compared to the low volume group (P = .021). Finally, age by volume interactions were found for knee extensor torque (P = .024), negative knee work (P = .018), and positive knee work (P = .019) but not for ankle and hip joint kinetics. These findings suggest less distal-to-proximal difference in positive joint work with high running volume in both young and middle-aged runners as a result of greater power generation at the ankle. Given the age main effects, our findings are also the first to suggest the age-related distal-to-proximal shift in joint kinetics appears in middle-aged runners.

Running does not increase symptoms or structural progression in people with knee osteoarthritis: data from the osteoarthritis initiative

Higher levels of moderate to vigorous physical activity improve all-cause mortality and cardiovascular events. However, the effect of running, a moderate to vigorous activity, in those with knee osteoarthritis (OA), a common arthritis that occurs with aging, a high-risk group for mortality and cardiovascular events, is unclear. Therefore, we aimed to evaluate the association of self-selected running on OA symptom and structure progression in people with knee OA. This nested cohort study within the Osteoarthritis Initiative (OAI) (2004-2014) included those at least 50 years old with OA in at least one knee. Runners were defined using a self-administered questionnaire at the 96-month visit. At baseline and 48-months, symptoms were assessed and radiographs were scored for Kellgren-Lawrence (KL) grade (2-4) and medial Joint Space Narrowing (JSN) score (0-3). We evaluated the association of self-selected running with outcomes: KL worsening, medial JSN worsening, new knee pain, and improved knee pain over 48 months, adjusting for baseline age, sex, body mass index (BMI), KL score, contralateral KL score, contralateral knee pain, and injury. If data were not available at the 48-month visit, then they were imputed from the 36-month visit. One thousand two hundred three participants had a mean age of 63.2 (7.9) years, BMI of 29.5 (4.6) kg/m², 45.3% male, and 11.5% runners. Data from 8% of participants required imputation. Adjusted odds ratios for KL grade worsening and new frequent knee pain were 0.9 (0.6-1.3) and 0.9 (0.6-1.6) respectively. Adjusted odds ratio for frequent knee pain resolution was 1.7 (1.0-2.8). Among individuals 50 years old and older with knee OA, self-selected running is associated with improved knee pain and not with worsening knee pain or radiographically defined structural progression. Therefore, self-selected running, which is likely influenced by knee symptoms and may result in lower intensity and shorter duration sessions of exercise, need not be discouraged in people with knee OA.

Physical Activity, the Compression of Morbidity, and the Health of the Elderly

The Compression of Morbidity hypothesis envisions a potential reduction of overall morbidity, and of health care costs, now heavily concentrated in the senior years, by compression of morbidity between an increasing age of onset of disability and the age of death, increasing perhaps more slowly1,2. For this scenario to be able to be widely achieved, largely through prevention of disease and disability, we need to identify variables which predict future ill health, modify these variables, and document the improvements in health that result3. Physical activity is perhaps the most obvious of the variables which might reduce overall lifetime morbidity.

Does sports participation (including level of performance and previous injury) increase risk of osteoarthritis? A systematic review and meta-analysis

BACKGROUND

To assess the relationship between sport and osteoarthritis (OA), and specifically to determine whether previous participation, in terms of level (elite or non-elite), type of sport, intensity or previous injury, was associated with OA.

METHODS

This systematic review was developed using PRISMA guidelines. Databases were searched (to May 2016). Narrative review and meta-analysis (with risk ratio (RR) and 95% CIs) approaches were undertaken where appropriate. Study quality was assessed using GRADE.

RESULTS

46 studies were included. Narratively, 31 studies reported an increased risk of OA, with 19 demonstrating an increased risk in elite athletes. There was an increased risk after sports exposure (irrespective of type; RR 1.37; 95% CI 1.14 to 1.64; 21 studies). It remained uncertain whether there was a difference in risk of OA between elite and non-elite athletes (RR 1.37; 95% CI 0.84 to 2.22; 17 studies). The risk was higher in soccer (RR 1.42; 95% CI 1.14 to 1.77; 15 studies) but lower in runners (RR 0.86; 95% CI 0.53 to 1.41; 12 studies). 9 studies showed an association with the intensity of sport undertaken and OA. 5 studies demonstrated a higher prevalence of OA following meniscectomies and anterior cruciate ligament tears. Overall, the evidence was of GRADE 'very low' quality.

CONCLUSIONS

There was very low-quality evidence to support an increased relationship between sports participation and OA in elite participants. It is unclear whether there is a difference in risk between elite and non-elite participants with further prospective studies needed to evaluate this. Pooled findings suggested that significant injuries were associated with OA in soccer players.

The effect of a six-month training program followed by a marathon run on knee joint cartilage volume and thickness in marathon beginners

PURPOSE

The purpose of this study was to investigate the effect of a 6-month period of intensive running followed by the participation at a marathon run on cartilage volume and thickness in knees of marathon beginners.

METHODS

Ten asymptomatic marathon beginners underwent a supervised 6-month training program, which was finalized by the participation at a marathon run. Three-dimensional quantitative magnetic resonance imaging was performed before the training program (baseline measurements) and 1 day after the marathon (follow-up measurements). Cartilage volume and thickness of the medial and lateral femur, medial and lateral tibia, and patella were measured using semiautomated cartilage segmentation and three dimensional data postprocessing.

RESULTS

Significant differences between baseline and follow-up measurements were observed at the lateral femur, where cartilage volume and thickness decreased by a mean of 3.2 ± 3.0% (p = 0.012) and 1.7 ± 1.6% (p = 0.010), respectively. No significant changes in cartilage volume and thickness were observed at the medial and lateral tibia, the medial femur, and the patella.

CONCLUSION

Significant cartilage loss was observed at the lateral femur; however, the measured values are comparable to previously reported precision errors for quantitative cartilage measurement and thus most likely not of clinical relevance. High-impact forces during long-distance running are well tolerated even in marathon beginners and do not lead to clinical relevant cartilage loss.

LEVEL OF EVIDENCE

IV.

Development and assessment of floor and ceiling items for the PROMIS physical function item bank

Introduction

Disability and Physical Function (PF) outcome assessment has had limited ability to measure functional status at the floor (very poor functional abilities) or the ceiling (very high functional abilities). We sought to identify, develop and evaluate new floor and ceiling items to enable broader and more precise assessment of PF outcomes for the NIH Patient-Reported-Outcomes Measurement Information System (PROMIS).

Methods

We conducted two cross-sectional studies using NIH PROMIS item improvement protocols with expert review, participant survey and focus group methods. In Study 1, respondents with low PF abilities evaluated new floor items, and those with high PF abilities evaluated new ceiling items for clarity, importance and relevance. In Study 2, we compared difficulty ratings of new floor items by low functioning respondents and ceiling items by high functioning respondents to reference PROMIS PF-10 items. We used frequencies, percentages, means and standard deviations to analyze the data.

Results

In Study 1, low (n = 84) and high (n = 90) functioning respondents were mostly White, women, 70 years old, with some college, and disability scores of 0.62 and 0.30. More than 90% of the 31 new floor and 31 new ceiling items were rated as clear, important and relevant, leaving 26 ceiling and 30 floor items for Study 2. Low (n = 246) and high (n = 637) functioning Study 2 respondents were mostly White, women, 70 years old, with some college, and Health Assessment Questionnaire (HAQ) scores of 1.62 and 0.003. Compared to difficulty ratings of reference items, ceiling items were rated to be 10% more to greater than 40% more difficult to do, and floor items were rated to be about 12% to nearly 90% less difficult to do.

Conclusions

These new floor and ceiling items considerably extend the measurable range of physical function at either extreme. They will help improve instrument performance in populations with broad functional ranges and those concentrated at one or the other extreme ends of functioning. Optimal use of these new items will be assisted by computerized adaptive testing (CAT), reducing questionnaire burden and insuring item administration to appropriate individuals.

Lifestyle risk factors predict disability and death in healthy aging adults

BACKGROUND

Associations between modifiable health risk factors during middle age with disability and mortality in later life are critical to maximizing longevity while preserving function. Positive health effects of maintenance of normal weight, routine exercise, and nonsmoking are known for the short and intermediate term. We studied the effects of these risk factors into advanced age.

METHODS

A cohort of 2327 college alumnae aged 60 years or more was followed annually (1986-2005) by questionnaires addressing health risk factors, history, and Health Assessment Questionnaire disability. Mortality data were ascertained from the National Death Index. Low-, medium-, and high-risk groups were created on the basis of the number (0, 1, ≥2) of health risk factors (overweight, smoking, inactivity) at baseline. Disability and mortality for each group were estimated from unadjusted data and regression analyses. Multivariable survival analyses estimated time to disability or death.

RESULTS

The medium- and high-risk groups had higher disability than the low-risk group throughout the study (P<.001). Low-risk subjects had onset of moderate disability delayed 8.3 years compared with high-risk subjects. Mortality rates were higher in the high-risk group (384 vs 247 per 10,000 person-years). Multivariable survival analyses showed the number of risk factors to be associated with cumulative disability and increased mortality.

CONCLUSION

Seniors with fewer behavioral risk factors during middle age have lower disability and improved survival. These data document that the associations of lifestyle risk factors on health continue into the ninth decade.

Why is osteoarthritis an age-related disease?

Although older age is the greatest risk factor for osteoarthritis (OA), OA is not an inevitable consequence of growing old. Radiographic changes of OA, particularly osteophytes, are common in the aged population, but symptoms of joint pain may be independent of radiographic severity in many older adults. Ageing changes in the musculoskeletal system increase the propensity to OA but the joints affected and the severity of disease are most closely related to other OA risk factors such as joint injury, obesity, genetics and anatomical factors that affect joint mechanics. The ageing changes in joint tissues that contribute to the development of OA include cell senescence that results in development of the senescent secretory phenotype and ageing changes in the matrix including formation of advanced glycation end-products that affect the mechanical properties of joint tissues. An improved mechanistic understanding of joint ageing will likely reveal new therapeutic targets to slow or halt disease progression. The ability to slow progression of OA in older adults will have enormous public health implications given the ageing of our population and the increase in other OA risk factors such as obesity.

Aging and osteoarthritis: the role of chondrocyte senescence and aging changes in the cartilage matrix

OBJECTIVE

Age-related changes in multiple components of the musculoskeletal system may contribute to the well established link between aging and osteoarthritis (OA). This review focused on potential mechanisms by which age-related changes in the articular cartilage could contribute to the development of OA.

METHODS

The peer-reviewed literature published prior to February 2009 in the PubMed database was searched using pre-defined search criteria. Articles, selected for their relevance to aging and articular chondrocytes or cartilage, were summarized.

RESULTS

Articular chondrocytes exhibit an age-related decline in proliferative and synthetic capacity while maintaining the ability to produce pro-inflammatory mediators and matrix degrading enzymes. These findings are characteristic of the senescent secretory phenotype and are most likely a consequence of extrinsic stress-induced senescence driven by oxidative stress rather than intrinsic replicative senescence. Extracellular matrix changes with aging also contribute to the propensity to develop OA and include the accumulation of proteins modified by non-enzymatic glycation.

CONCLUSION

The effects of aging on chondrocytes and their matrix result in a tissue that is less able to maintain homeostasis when stressed, resulting in breakdown and loss of the articular cartilage, a hallmark of OA. A better understanding of the basic mechanisms underlying senescence and how the process may be modified could provide novel ways to slow the development of OA.

Reduced disability and mortality among aging runners: a 21-year longitudinal study

BACKGROUND

Exercise has been shown to improve many health outcomes and well-being of people of all ages. Long-term studies in older adults are needed to confirm disability and survival benefits of exercise.

METHODS

Annual self-administered questionnaires were sent to 538 members of a nationwide running club and 423 healthy controls from northern California who were 50 years and older beginning in 1984. Data included running and exercise frequency, body mass index, and disability assessed by the Health Assessment Questionnaire Disability Index (HAQ-DI; scored from 0 [no difficulty] to 3 [unable to perform]) through 2005. A total of 284 runners and 156 controls completed the 21-year follow-up. Causes of death through 2003 were ascertained using the National Death Index. Multivariate regression techniques compared groups on disability and mortality.

RESULTS

At baseline, runners were younger, leaner, and less likely to smoke compared with controls. The mean (SD) HAQ-DI score was higher for controls than for runners at all time points and increased with age in both groups, but to a lesser degree in runners (0.17 [0.34]) than in controls (0.36 [0.55]) (P < .001). Multivariate analyses showed that runners had a significantly lower risk of an HAQ-DI score of 0.5 (hazard ratio, 0.62; 95% confidence interval, 0.46-0.84). At 19 years, 15% of runners had died compared with 34% of controls. After adjustment for covariates, runners demonstrated a survival benefit (hazard ratio, 0.61; 95% confidence interval, 0.45-0.82). Disability and survival curves continued to diverge between groups after the 21-year follow-up as participants approached their ninth decade of life.

CONCLUSION

Vigorous exercise (running) at middle and older ages is associated with reduced disability in later life and a notable survival advantage.

Long distance running and knee osteoarthritis. A prospective study

BACKGROUND

Prior studies of the relationship of physical activity to osteoarthritis (OA) of the knee have shown mixed results. The objective of this study was to determine if differences in the progression of knee OA in middle- to older-aged runners exist when compared with healthy nonrunners over nearly 2 decades of serial radiographic observation.

METHODS

Forty-five long-distance runners and 53 controls with a mean age of 58 (range 50-72) years in 1984 were studied through 2002 with serial knee radiographs. Radiographic scores were two-reader averages for Total Knee Score (TKS) by modified Kellgren & Lawrence methods. TKS progression and the number of knees with severe OA were compared between runners and controls. Multivariate regression analyses were performed to assess the relationship between runner versus control status and radiographic outcomes using age, gender, BMI, education, and initial radiographic and disability scores among covariates.

RESULTS

Most subjects showed little initial radiographic OA (6.7% of runners and 0 controls); however, by the end of the study runners did not have more prevalent OA (20 vs 32%, p =0.25) nor more cases of severe OA (2.2% vs 9.4%, p=0.21) than did controls. Regression models found higher initial BMI, initial radiographic damage, and greater time from initial radiograph to be associated with worse radiographic OA at the final assessment; no significant associations were seen with gender, education, previous knee injury, or mean exercise time.

CONCLUSIONS

Long-distance running among healthy older individuals was not associated with accelerated radiographic OA. These data raise the possibility that severe OA may not be more common among runners.

Regular vigorous physical activity and disability development in healthy overweight and normal-weight seniors: a 13-year study

OBJECTIVES

We examined the relationship of regular exercise and body weight to disability among healthy seniors.

METHODS

We assessed body mass index (BMI) and vigorous exercise yearly (1989-2002) in 805 participants aged 50 to 72 years at enrollment. We studied 4 groups: normal-weight active (BMI< 25 kg/m(2); exercise> 60 min/wk); normal-weight inactive (exercise<or= 60 min/wk); overweight active (BMI>or= 25 kg/m(2)); and overweight inactive. Disability was measured with the Health Assessment Questionnaire (0-3; 0= no difficulty, 3= unable to do). We used multivariable analysis of covariance to determine group differences in disability scores after adjustment for determinants of disability.

RESULTS

The cohort was 72% men and 96% White, with a mean age of 65.2 years. After 13 years, overweight active participants had significantly less disability than did overweight inactive (0.14 vs 0.19; P= .001) and normal-weight inactive (0.22; P= .03) participants. Similar differences were found between normal-weight active (0.11) and normal-weight inactive participants (P< .001).

CONCLUSIONS

Being physically active mitigated development of disability in these seniors, largely independent of BMI. Public health efforts that promote physically active lifestyles among seniors may be more successful than those that emphasize body weight in the prevention of functional decline.

Associations of changes in exercise level with subsequent disability among seniors: a 16-year longitudinal study

BACKGROUND

The effect of changes in physical exercise on progression of musculoskeletal disability in seniors has rarely been studied.

METHODS

We studied a prospective cohort annually from 1984 to 2000 using the Health Assessment Questionnaire Disability Index (HAQ-DI). The cohort included 549 participants, 73% men, with average end-of-study age of 74 years. At baseline and at the end of the study, participants were classified as "High" or "Low" vigorous exercisers using a cut-point of 60 min/wk. Four groups were formed: "Sedentary" (Low-->Low; N = 71), "Exercise Increasers" (Low-->High; N = 27), "Exercise Decreasers" (High-->Low; N = 73), and "Exercisers" (High-->High; N = 378). The primary dependent variable was change in HAQ-DI score (scored 0-3) from 1984 to 2000. Multivariate statistical adjustments using analysis of covariance included age, gender, and changes in three risk factors, body mass index, smoking status, and number of comorbid conditions. Participants also prospectively provided reasons for exercise changes.

RESULTS

At baseline, Sedentary and Increasers averaged little exercise (16 and 22 exercise min/wk), whereas Exercisers and Decreasers averaged over 10 times more (285 and 212 exercise min/wk; p <.001). All groups had low initial HAQ-DI scores, ranging from 0.03 to 0.08. Increasers and Exercisers achieved the smallest increments in HAQ-DI score (0.17 and 0.11) over 16 years, whereas Decreasers and Sedentary fared more poorly (increments 0.27 and 0.37). Changes in HAQ-DI score for Increasers compared to Sedentary were significantly more favorable (p <.05) even after multivariate statistical adjustment.

CONCLUSIONS

Inactive participants who increased exercise achieved excellent end-of-study values with increments in disability similar to those participants who were more active throughout. These results suggest a beneficial effect of exercise, even when begun later in life, on postponement of disability.

Impact of osteoarthritis on sports careers

The number of people participating in sports continues to increase. The relationship between sports participation, joint injury, and subsequent osteoarthritis is complex. A history of joint injury and participation in high joint loading sports increases the risk of subsequent osteoarthritis changes in affected joints. The impact of osteoarthritis on sports careers depends on multiple factors including the joint involved, the location within that joint, and the physical demands of the chosen sport.

Ground reaction forces and kinematics in distance running in older-aged men

PURPOSE

The biomechanics of distance running has not been studied before in older-aged runners but may be different than in younger-aged runners because of musculoskeletal degeneration at older age. This study aimed at determining whether the stance phase kinematics and ground reaction forces in running are different between younger- and older-aged men.

METHOD

Lower-extremity kinematics using three-dimensional motion analysis and ground reaction forces (GRF) using a force plate were assessed in 16 older-aged (55-65 yr) and 13 younger-aged (20-35 yr) well-trained male distance runners running at a self-selected (SRS) and a controlled (CRS) speed of 3.3 m.s-1.

RESULTS

The older subjects ran at significantly lower self-selected speeds than the younger subjects (mean 3.34 vs 3.77 m.s-1). In both speed conditions, the older runners exhibited significantly more knee flexion at heel strike and significantly less knee flexion and extension range of motion. No age group differences were present in subtalar joint motion. Impact peak force (1.91 vs 1.70 BW) and maximal initial loading rate (107.5 vs 85.5 BW.s-1) were significantly higher in the older runners at the CRS. Maximal peak vertical and anteroposterior forces and impulses were significantly lower in the older runners at the SRS.

CONCLUSION

The biomechanics of running is different between older- and younger-aged runners on several relevant parameters. The larger impact peak force and initial loading rate indicate a loss of shock-absorbing capacity in the older runners. This may increase their susceptibility to lower-extremity overuse injuries. Moreover, it emphasizes the focus on optimizing cushioning properties in the design and prescription of running shoes and suggests that older-aged runners should be cautious with running under conditions of high impact.

Update on osteoarthritis part 1: current concepts and the relation to exercise

There appears to be an increased risk of lower limb osteoarthritis in participants of repetitive, high impact sports, and this is strongly associated with joint injury. There seems to be little risk associated with recreational running. Assessment of risk for osteoarthritis should take into account the nature of the sport, intensity of training, presence of previous injury, body mass index, and occupation.

Industrial medicine and acute musculoskeletal rehabilitation. 6. Occupational health for special populations

This self-directed learning module highlights work-related injuries in specific patient populations that the physiatrist may encounter. This chapter focuses on evaluating work-related injuries in the aging and disabled population. Specific problems encountered in pregnant working women and the dental profession are also summarized. Specific biologic and/or environmental factors as they relate to workers in the specific populations are reviewed. Strategies for evaluation, rehabilitation, and health care management of these workers are discussed.

OVERALL ARTICLE OBJECTIVES

(a) To be aware of specific needs and environmental factors for disabled, aging, pregnant, and dental workers and (b) to identify what may precipitate injury for disabled, aging, pregnant, and dental workers.

Dose-response of physical activity and low back pain, osteoarthritis, and osteoporosis

PURPOSE

The purpose of this study was to examine the evidence for causal relationships between physical activity (PA) and low back pain (LBP), osteoarthritis (OA), and osteoporosis (OP), and for dose-response relations involved.

METHODS

Computer database searches and personal retrieval systems were used to locate relevant literature.

RESULTS

PA can be effective in preventing LBP (Category A) but prolonged, heavy loading can lead to LBP (Category C). Specific exercises have not been found effective in treatment of acute LBP (Category A), but PA can be effective in chronic LBP (Category B), especially for diminishing the effects of deconditioning. No evidence indicates that PA directly prevents OA. Large amounts of intensive PA involving high impacts or torsional loadings or causing injuries increases risk of OA (Category C). Light or moderate PA does not increase the risk of OA (Category C). PA can be effective in the treatment and rehabilitation of OA (Category B). High-intensity loading is osteogenic and possibly useful in prevention of OP (Category A) at the loaded site, but low to moderate loading is not osteogenic (Category D). Static efforts and slow movements are ineffective or less effective than fast application of force (Category B). The types of PA to attain the effects mentioned above are known except in the case of prevention of LBP, but dose-response relationships are poorly known; at best, semiquantitatively on the basis of just a few studies.

CONCLUSION

Given the shown primary and/or secondary preventative effectiveness of PA regarding LBP, OA, and OP, research to elucidate the inadequately known dose-response relations should be given high priority.

Interview versus questionnaire for assessing physical loads in the population-based MUSIC-Norrtälje Study

BACKGROUND

MUSIC-Norrtälje study is a case-referent study, the aim of which is to find risk and health factors for low back and neck/shoulder disorders. In this part of the study, the interview technique and the self-administered questionnaire used for assessment of physical loads are described and the inter-method reliability of parts of the self-administered questionnaire is estimated. The distribution of exposure levels in a general population is also described.

METHODS

The study period was three years from November 1993 to November 1996, and the study subjects totaled 2,480 persons (813 female and 610 male referents, 380 female and 315 male low back cases, 252 female and 106 male neck/shoulder cases). The interview concerned "a typical working day" during the preceding 12 months and comprised assessment of energy expenditure, work postures, and manual materials handling for work and leisure time, including regular sport activities. The self-administered questionnaire comprised 18 questions, each covering 5 different points of time: right now, 5, 10, 15, 20 years ago. The answers to eight of the questions about current conditions were compared to corresponding interview responses. The interview was considered as the "gold standard."

RESULTS

Ninety-eight percent of the subjects completed the interview without any great difficulties. According to the interview, the distributions of different exposure levels were generally positively skewed, i.e., the frequency of highly exposed subjects was low in the study base. The correlation between interview and questionnaire responses among the referents was high for time spent "sitting at work" (r = 0.82), "VDU work" (r = 0.87), and work related "motor vehicle driving" (r = 0.80). The correlation was moderate for work-related "hands above shoulder level" (rs = 0.63), and "hands below knee level (trunk flexion)" (rs = 0.66). The correlation was lower for leisure time activities such as "domestic work" (r = 0.55), "time for own activities" (r = 0.39), and "sitting during leisure time" (r = 0.38). Subjects seeking care for low back or neck/shoulder disorder estimated equally correctly or not, as had the referents. However, non-differential misclassification was present in all questions, which will attenuate observed estimates of the relative risk.

CONCLUSIONS

Even though interview data are preferable, questionnaire data may be useful for assessing well-defined work tasks and for "sitting at work."

The impact of hemiparalysis on the expression of osteoarthritis

OBJECTIVE

Primary generalized osteoarthritis (OA), the most prevalent joint disease, is usually symmetric. Sporadic case reports mention decreased OA manifestations in limbs in which there are neurologic deficits, but no systematic research has been published. The aim of the present study was to examine these observations in a planned and controlled survey in a group of patients with OA.

METHODS

Seventy-five geriatric patients with a history of stroke and hemiparalysis were studied clinically and radiographically (hand radiographs; graded according to a modified Altman method) for the presence and the degree of OA in the hands. Detailed clinical and radiologic scores were calculated for each hand. Demographic, occupational, and neurologic data were collected. Patients with other joint or neurologic conditions were excluded. A group of 55 elderly patients without stroke were similarly studied (controls). Scores in the paralyzed hand were compared with those in the nonparalyzed hand in the stroke patients and subgroups (by Student's paired t-test and Wilcoxon test). Scores in the dominant hands were compared with those in the nondominant hands in stroke patients and control subjects (by Student's paired t-test and Mann-Whitney test). Correlation between the degree of neurologic damage and OA asymmetry (Pearson's correlation coefficient) was also sought.

RESULTS

Paralyzed hands showed significantly fewer OA changes than nonparalyzed hands, both clinically and radiologically. This trend, accentuated in patients with more severe paralysis, disappeared in those with mild residual paresis. Asymmetry of OA was more pronounced in patients with flaccid, compared with spastic, paralysis. The degree of paralysis and loss of muscle strength correlated with the degree of OA asymmetry. Women had significantly higher OA scores than men. In the control group, dominant hands had higher OA scores, but this finding was concealed among hemiparalyzed patients. Lifetime gross occupational load and present grip strength did not correlate with the degree of OA.

CONCLUSION

In elderly patients, hemiparalysis reduces ipsilateral hand expression of OA, while OA is accentuated (or increased) in the dominant hand of patients without paralysis. This first systematic study confirms the findings of previous case reports and lends support to the role of biomechanical factors in the development of OA.

Osteoarthrosis of the hip in women and its relationship to physical load from sports activities

In a case-control study, the relationship between sporting activities and osteoarthrosis of the hip in women was investigated. The study base comprised Swedish women 50 to 70 years of age between 1991 and 1994. Case subjects (N = 230) had had total hip replacements because of primary osteoarthrosis of the hip, and control subjects (N = 273) were randomly selected women without hip problems from the study base. All women were interviewed about sports activities to the age of 50, health status, smoking habits, occupational history, and work in the home. Three exposure classes were defined based on total hours of sports activities aggregated to the age of 50. The relative risks of developing osteoarthrosis of the hip leading to total hip replacement was 2.3 (confidence interval, 1.5 to 3.7) for those with high sports exposure and 1.5 (0.9 to 2.5) for those with medium sports exposure compared with those with low exposure. The relative risks were adjusted for age, occupational physical load, body mass index, hormone therapy, and smoking. Physical load from sporting activities seems to be a moderate risk factor for women for the development of severe osteoarthrosis of the hip. Participation in sports was low, and therefore individual risk estimates for different sports activities were not possible to obtain.

Winner of the 1996 Cabaud Award. The effect of lifelong exercise on canine articular cartilage

The effect of long-term exercise on canine knees was studied to determine whether an increased level of lifelong weightbearing exercise causes degeneration, or changes that may lead to degeneration, of articular cartilage. Eleven dogs were exercised on a treadmill at 3 km/hr for 75 minutes 5 days a week for 527 weeks while carrying jackets weighing 130% of their body weight. Ten control dogs were allowed unrestricted activity in cages for the 550 weeks. At the completion of the study all knee joints were inspected for evidence of joint injury and degeneration. Articular cartilage surfaces from the medial tibial plateau were examined by light microscopy, the cartilage thickness was measured, and the intrinsic material properties were determined by mechanical testing. No joints had ligament or meniscal injuries, cartilage erosions, or osteophytes. Light microscopy did not demonstrate cartilage fibrillation or differences in safranin O staining of the tibial articular cartilages between the two groups. Furthermore, the tibial articular cartilage thickness and mechanical properties did not differ between the two groups. These results show that a lifetime of regular weightbearing exercise in dogs with normal joints did not cause alterations in the structure and mechanical properties of articular cartilage that might lead to joint degeneration.

Osteoarthrosis of the hip in women and its relation to physical load at work and in the home

OBJECTIVES

The aim of this case referent study was to investigate the relation between physical workload and osteoarthrosis of the hip in women.

METHODS

The study base comprised all women of ages 50-70 years, living in five counties and four towns in Sweden 1991-1994. Cases (n = 230), who had undergone total hip replacement for primary osteoarthrosis of the hip were identified by means of the Swedish National Register of Total Hip Replacements, and the referents (n = 273) were women without hip problems randomly selected from the study base. All women were interviewed about state of health, smoking habits, occupational history, work in the home, sports activities, etc. Each subject's history of occupational work and work in the home up to the age of 50 was divided into periods within each of which the work tasks were similar, and a questionnaire for each such period was filled in by the participants. On the basis of information given by the referents, the women were classified as having had low, medium, and high exposure to different factors. Relative risks (RRs) and 95% confidence intervals (CI) were calculated.

RESULTS

Physically demanding tasks at work and in the home were associated with increased RRs of osteoarthrosis of the hip in those with high exposure compared with the low exposure group. A RR in the range of 2 or higher was found for those who frequently jumped or moved between different levels (RR = 2.1, CI 1.9, 4.2), who frequently climbed stairs (RR = 2.1, CI 1.2, 3.6), and who had physically demanding tasks outside occupational life (RR = 2.3, CI 1.5, 3.6). The highest RR (RR = 4.3, CI 1.7, 11.0) was found for those exposed to high physical loads both at work and during sports activities.

CONCLUSION

High physical loads at work and in the home up to the age of 50 seem to be risk factors for development of severe osteoarthrosis of the hip in women.

The aging tendon

After maturation tendons undergo many biochemical, cellular, mechanical and pathological changes that bring about a general decline in the structure and function of the tendon. This decline in the aging tendon is characterized by a reduced ability to adapt to environmental stress and loss of tissue homeostasis. The tendon's adaptability to these changes will decide the rate and the success of treatment of a tendon injury. This review examines these changes and also looks at how we can curtail their progression through exercise and lifestyle modification.

Reproducibility of a questionnaire for assessment of physical load during work and leisure time. Stockholm MUSIC I Study Group. MUSculoskeletal Intervention Center

A self-administered questionnaire on physical load in lifetime occupational work, in present job, and in present leisure activities was tested for reproducibility with the test-retest method in 126 male and 217 female workers from 30 occupations. The questionnaire contained 92 questions and nine different response scales. The results indicated that questions concerning physical activity retrospectively and in the present job, vibrations in the present job, working postures involving the whole body, and questions concerning specific leisure activities (eg ball games, skiing, etc) seem to offer sufficient reproducibility to be worth testing for validity, at least at a 5-point ordinal level. Questions concerning working postures involving parts of the body, including awkward postures, and questions concerning manual materials handling seem to offer too poor reproducibility to be used in studies in which the aim is to quantify duration in proportions of a typical working day and frequencies in times per hour. Questions concerning level of physical activity and exertion in domestic work seem to offer too poor reproducibility to be used at a 5-point ordinal level. Gender, age, and musculoskeletal complaints did not influence the reproducibility to any great extent.

Prevention of osteoporotic fractures: possibilities, the role of exercise, and limitations

The Compression of Morbidity paradigm seeks to reduce lifetime illness and morbidity by compressing the dominant morbidity, that of the senior years, between an increasing age of onset of morbidity and a more slowly increasing average age at death. Fractures, often associated with osteoporosis, cause a substantial part of this morbidity. For morbidity resulting from fractures to be reduced, the age-specific incidence of fractures needs to decline, since treatment of fractures after they occur is not likely to prove a major benefit. Thus, the risk factors need to be identified and appropriate preventive interventions undertaken. The medical model seeks to diagnose, then to treat those with disease. In considering prevention, many apply the medical model. The disease is "osteoporosis", we must identify people with this disease and then treat them. The public health model, in contrast, seeks to prevent "disease" in all susceptibles. The disease is "morbidity resulting from fractures". The fatal flaws in the medical screening approach will be discussed, together with a lament that this conference was not entitled: "Recent Progress in the Prevention of Morbidity Associated with Fractures". Osteoporosis is only one of many factors associated with increased morbidity resulting from fractures. A fracture management model for reduction in this morbidity will be presented. Osteoporosis finds its genesis in many well-identified risk factors, including age, sex, estrogen levels, and exercise levels, together with positive (e.g. calcium, estrogen) and negative (corticosteroids) effects of medications. Falls, the other main branch of the model, find their genesis is such risk factor as slippery floors, medication side effects, and co-morbid conditions, often with their own antecedent risk factors. Together, over twenty preventable risk factors contribute to the major morbidity associated with fractures.

Relationship of running to musculoskeletal pain with age. A six-year longitudinal study

OBJECTIVE

To determine, by longitudinal study, whether long-distance running, maintained for many years, is associated with increased musculoskeletal pain with age.

METHODS

A 6-year prospective longitudinal study of 410 runners' club members and 289 community controls, age 53-75 years at study initiation, was conducted. Subjects were also categorized as ever-runners (n = 488) and never-runners (n = 211). The primary dependent variable was pain score as indicated on a horizontal double-anchored analog scale; data for this variable were available beginning in 1987. Statistical adjustment for age, education level, smoking, alcohol consumption, history of arthritis, and presence of other major medical conditions was done by analysis of covariance. Further analyses of previously reported associations of regular vigorous physical activity with decreased disability and mortality after 9 years were performed.

RESULTS

The degree of musculoskeletal pain was slightly lower in the exercise group compared with controls, and the difference was statistically significant for women but not for men. Average adjusted pain scores for men were 18.3 (SEM 0.8) in runners' club members, 20.2 (1.2) in controls, 18.6 (0.8) in ever-runners, and 20.3 (1.6) in never-runners. For women, these scores were 17.5 (1.8) in runners' club members versus 22.8 (1.4) in controls (P < 0.05), and 17.2 in ever runners versus 23.7 (1.5) in never-runners (P < 0.002). Disability had continued to develop in runners' club members at a rate only one-third that in the controls after 9 years of observation. Mortality over 9 years consisted of 51 deaths, of which 41 were in the control group and only 10 were among runners' club members.

CONCLUSION

Vigorous running activity over many years is not associated with an increase in musculoskeletal pain with age, and there may be a moderate decrease in pain, particularly in women. Vigorous physical activity is associated with greatly decreased levels of disability and with decreased mortality rates.

Correlation between physical activity and the gait characteristics and ankle joint flexibility of the elderly

The correlation between the type, duration and intensity of physical activity on the gait characteristics and the range of active ankle joint motion of the elderly were investigated in this study. Three-dimensional (3D) kinetic and kinematic assessments were performed on the normal walking patterns of 59 healthy elderly male and female subjects (aged 60-79 years). Gait analysis was performed using a high-speed video-based (3D) motion analysis system with synchronized ground-reaction force measurements. The maximal active range of motion (RoM) of the ankle joint complex of each subject was determined using an external six-degree-of-freedom flexibility assessment device. Physical activity levels were classified based on energy expenditure requirements. In general the results suggest that habitual level of physical activity did not have a significant effect on the kinetic or kinematic variables during walking, or the maximal ankle joint range of motion. Differences in ankle joint RoM and gait variables were found based on gender. No distinct benefit with respect to ankle joint range of motion or gait characteristics was provided with participation in higher-energy intensive physical activities in comparison to physical activities requiring low to moderate energy expenditures. It is speculated that the benefits of physical activity may be more pronounced in activities which demand rapid muscular strength and control movements such as recovering from a fall or obstacle avoidance. RELEVANCE: Participation in low-energy intensity activities provides the same benefits to ankle joint flexibility and locomotion, without the added risk of injury associated with high-energy intensity sports. This finding has important implications with respect to physical activity programmes for the elderly with an objective to maintain or improve independent mobility.

Predictors of physical disability after age 50. Six-year longitudinal study in a runners club and a university population

Predictors of disability were studied over 6 years among 50- to 80-year-old members of a runners club (N = 407) and a university population (N = 299). Data have been collected annually since 1984 on sociodemographic characteristics, health habits, medical history, medication use, family history, psychological parameters, and physical disability as measured by the Health Assessment Questionnaire. Members of the runners club, compared to university participants, had better overall health and less disability at baseline (0.03 versus 0.08) and at 6-year follow-up (0.04 versus 0.24). Predictors of greater subsequent disability among university participants were greater baseline disability, greater medication use, greater number of pack-years of cigarette smoking, older age, being unmarried, higher blood pressure, history of arthritis, and less physical activity compared to one's peers. In addition, changes in characteristics during follow-up that were independently associated with greater disability were development of joint pain, arthritis, or bone fracture and increased body mass index. Predictors of greater disability in the runners group included greater baseline disability, being a nonrunner at baseline, greater dietary salt intake, more years of running at baseline, and greater frequency of physician visits for running injuries. Greater disability in this group also was associated with increases in medication use, declining alcohol consumption, and development of joint pain over 6 years. Results of this study suggest that physical disability is linked to a constellation of characteristics, health habits, medical history, comorbidities, and marital status. While self-selection bias cannot be ruled out entirely, these data are consistent with the hypothesis that those who engage in high levels of physical activity beyond middle age will continue to maintain better functional abilities.

Exercise and the musculoskeletal system

1. Normal joints in individuals of all ages may tolerate prolonged and vigorous exercise without adverse consequences or accelerated development of OA. 2. Individuals who have underlying muscle weakness or imbalance, neurological abnormalities, anatomical variances, and who engage in significant amounts of exercise that stress the lower extremities, may accelerate the development of OA. 3. Individuals who have suffered injuries to supporting structures may also be susceptible to accelerated development of OA in weight-bearing joints, even without increased stress to the joint from exercise. 4. Certain individuals with established degenerative or inflammatory arthritis may benefit from supervised exercise programmes. 5. Still more information is needed so that physicians can identify subjects at risk for the development of OA, advise the millions of participants about the beneficial and deleterious effects of regular exercise and sports participation, and develop successful rehabilitation programmes for injured joints.

Physical activity epidemiology as applied to elderly populations

Physical activity epidemiological studies provide one of many types of research evidence that are necessary to assess the importance of physical activity to health. Available epidemiological evidence, when coupled with relevant experimental and clinical research, suggests that physical activity has the potential to favourably influence the development and progression of a variety of chronic diseases and conditions that are a burden to public health. The evidence is only beginning to emerge for elderly populations, however, thereby highlighting an important void in our scientific knowledge. Attempting to increase the level of physical activity of elderly people raises three important issues. First, improving adherence to a physically active life-style requires assistance of behavioural scientists, either through direct intervention, or through research that can help the elderly identify and overcome impediments to physical activity. Second, many elderly people have diseases that can limit their physical ability, but exercise scientists can assist by prescribing exercise that is both efficacious and safe given the level of limitation. Third, the number of injuries may increase with increased physical activity in elderly persons. Epidemiologists and exercise scientists working in the area of injury control can determine which activities are safe at specific levels of physical ability and function. To quote one of the originators of exercise physiology, Per Olaf Astrand (1992), 'As a consequence of diminished exercise tolerance, a large and increasing number of elderly people will be living below, at, or just above "thresholds" of physical ability, needing only a minor intercurrent illness to render them completely dependent'. Physical activity can help to push back that 'threshold of physical ability' and thereby improve physical functioning. As physical function improves, there is a propensity to perform even greater amounts of physical activity that may be essential to the quality and perhaps quantity of life for an elderly person.

Osteophytosis of the knee: association with changes in weight-bearing exercise

Osteoarthritis has been held to result from wear and tear. We addressed this hypothesis by analysis of anteroposterior radiographs of the knees of 51 subjects with mean age of 60 years who regularly practiced weight-bearing exercise. Radiographs were assessed for longitudinal changes in spur formation over a two-year period. The results showed a negative association between changes in weight-bearing exercise and changes in the rate of spur development in both males and females. The findings suggest that increasing repetitive impulse loading in the form of regular painless weight-bearing activity does not promote osteophytosis (or perhaps degenerative disease) in knee joints.

Improvement in intergenerational health

Differences in health status between subjects, their parents, and their children were analyzed in 2206 subjects who had attended the University of Pennsylvania during the 1939 to 1940 school year. Subjects compared their overall health status at the average age of 70 with that of their same-sex parent at the same age and with that of their same-sex child at the approximate average age of 45, providing reasons for reported differences. Thus, health status in family members of the same sex at the same age in 1988 was compared with that in approximately 1963. Subject health was strikingly improved compared with that of their parents a generation earlier, with 58% reporting their health to be better or much better, and only 9% reporting it to be worse or much worse (P less than .001). The major reasons for the difference were decreased prevalence of chronic conditions and healthier life-styles. The same results were observed in a community-based population of 317 subjects and, even more strikingly, in a group of 422 aging long-distance runners. These observations suggest substantial improvement in senior health status over the past quarter century in selected populations, and they contrast with equivocal changes that have been noted with traditional serial survey techniques.

Lower extremity injuries in runners. Advances in prediction

Recreational and competitive running is practised by many individuals to improve cardiorespiratory function and general well-being. The major negative aspect of running is the high rate of injuries to the lower extremities. Several well-designed population-based studies have found no major differences in injury rates between men and women; no increasing effect of age on injuries; a declining injury rate with more years of running experience; no substantial effect of weight or height; an uncertain effect of psychological factors; and a strong effect of previous injury on future injuries. Among the modifiable risk factors studied, weekly distance is the strongest predictor of future injuries. Other training characteristics (speed, frequency, surface, timing) have little or no effect on future injuries after accounting for distance run. More studies are needed to address the effects of appropriate stretching practices and abrupt change in training patterns. For recreational runners who have sustained injuries, especially within the past year, a reduction in running to below 32 km per week is recommended. For those about to begin a running programme, moderation is the best advice. For competitive runners, great care should be taken to ensure that prior injuries are sufficiently healed before attempting any racing event, particularly a marathon.

Effect of changes in weight-bearing exercise on lumbar bone mass after age fifty

This two year longitudinal study of 40 healthy subjects over age fifty (27 exercisers, 13 non-exercisers) was designed to evaluate the impact of weight-bearing exercise on lumbar bone mineral density as assessed by quantitative computed tomography. In both males and females exercising at moderate levels, a high correlation was found between changes in exercise and changes in bone density (r = 0.78 and 0.91, respectively P less than 0.002). For extreme levels of exercise (greater than 300 min/week in females over age fifty, and greater than 200 min/week in males over age seventy) bone density was low, confirming earlier cross-sectional results. Subjects without change in their exercise levels and non-exercisers lost similar amounts of bone. Increasing body mass index was identified as a protective factor with regard to lumbar bone loss. We conclude that in exercisers continuation of weight-bearing exercise is mandatory to prevent excessive bone loss. Extreme levels of exercise may be detrimental to bone density in subjects over age fifty years.

Occupation, income, and education as independent covariates of arthritis in four national probability samples

The strong associations between education level and prevalence and severity of arthritis have recently been investigated, with some suggestion that the relationships might be causal. Data from 4 national probability samples were analyzed, in which occupation and income were measured currently and prior to the development of arthritis. These data indicate that previous studies overestimated the strength of the association between schooling and arthritis because income and, especially, occupation were not analyzed as separate covariates. The overestimate appears to be especially high for persons currently employed, for men, and for persons employed in dangerous jobs. Health policy strategies directed toward reducing arthritis rates require not simply a focus on education, but the additional socioeconomic status dimensions of income and occupational safety and health.

Therapeutic exercise for rheumatoid arthritis and osteoarthritis

Therapeutic exercise in rheumatoid arthritis and osteoarthritis may be useful in improving aerobic capacity, strengthening muscles, improving endurance and increasing flexibility. This article reviews the major studies of exercise in these conditions and summarizes the authors recommendations regarding the use of therapeutic exercise in the treatment of rheumatoid arthritis osteoarthritis.

Running, osteoarthritis, and bone density: initial 2-year longitudinal study

PURPOSE

The purpose of this study was to present the 2-year follow-up results examining associations of repetitive long-term physical impact (running) with osteoarthritis and osteoporosis in 34 members of a running club now aged 52 to 74 years and 34 matched control subjects.

PATIENTS AND METHODS

Roentgenograms of the hands, lateral lumbar spine, and knees were assessed in pairs (1984 and 1986) without knowledge of running status. Computerized scans of the first lumbar vertebrae were obtained to quantify bone mineral.

RESULTS

A decrease in bone density over the 2-year period was statistically significant for nearly all subjects, especially for runners who decreased their running habits. At the 2-year follow-up, runners maintained greater bone density. Progression of the roentgenographic scores for osteoarthritis demonstrated a statistically significant increase in almost all groups in this normative population over the 2-year period. Female runners had more spur formation in the weight-bearing knee roentgenograms than did control subjects.

CONCLUSION

With the possible exception of spur formation in women, running did not appear to influence the development of radiologic osteoarthritis in the populations studied.

Endurance Training in Middle-Aged Male Physicians

In brief: Vigorous exercise has been associated with reduced cardiovascular risk factors and a lower incidence of coronary heart disease. To determine the effects of endurance training on middle-aged men, a group that is at risk for heart disease, two groups of Physicians were surveyed: 1,269 runners (members of the American Medical Joggers Association who had been running at least 10 miles per week) and 683 nonrunners (members of the AMA). These groups were chosen because they are similar in age, sex, life-style, profession, socioeconomic position, and knowledge about health. Results showed that the runners had lower body weight and reduced cardiovascular risk factors, and that they smoked fewer cigarettes. However, prospective studies are needed to determine both the risks and benefits of endurance exercise.