Pekka Oja

The International Physical Activity Questionnaire (IPAQ): a study of concurrent and construct validity

INTRODUCTION The International Physical Activity Questionnaire (IPAQ) was developed to measure health-related physical activity (PA) in populations. The short version of the IPAQ has been tested extensively and is now used in many international studies. The present study aimed to explore the validity characteristics of the long-version IPAQ. SUBJECTS AND METHODS Forty-six voluntary healthy male and female subjects (age, mean +/- standard deviation: 40.7 +/- 10.3 years) participated in the study. PA indicators derived from the long, self-administered IPAQ were compared with data from an activity monitor and a PA log book for concurrent validity, and with aerobic fitness, body mass index (BMI) and percentage body fat for construct validity. RESULTS Strong positive relationships were observed between the activity monitor data and the IPAQ data for total PA (rho = 0.55, P < 0.001) and vigorous PA (rho = 0.71, P < 0.001), but a weaker relationship for moderate PA (rho = 0.21, P = 0.051). Calculated MET-h day(-1) from the PA log book was significantly correlated with MET-h day(-1) from the IPAQ (rho = 0.67, P < 0.001). A weak correlation was observed between IPAQ data for total PA and both aerobic fitness (rho = 0.21, P = 0.051) and BMI (rho = 0.25, P = 0.009). No significant correlation was observed between percentage body fat and IPAQ variables. Bland-Altman analysis suggested that the inability of activity monitors to detect certain types of activities might introduce a source of error in criterion validation studies. CONCLUSIONS The long, self-administered IPAQ questionnaire has acceptable validity when assessing levels and patterns of PA in healthy adults.

Randomised controlled trial of effect of high-impact exercise on selected risk factors for osteoporotic fractures

BACKGROUND Osteoporotic fractures among the elderly are common, and without preventive measures the burden of these fractures on health-care systems will increase further. The purpose of this randomised controlled study was to evaluate, in premenopausal women, the effects of high-impact loading on several determinants osteoporotic fractures. METHODS 98 healthy, sedentary female volunteers aged 35-45 years were randomly assigned to either a training (n = 49) or a control group (n = 49). Progressive high-impact exercises were done three times per week for 18 months. We measured bone mineral density (BMD) in specific axial and lower-limb sites, by dual-energy X-ray absorptiometry, at baseline and after 12 and 18 months. Maximum isometric strength, muscular and cardiovascular performance, and dynamic balance were also assessed. FINDINGS BMD at the femoral neck, a weightbearing site, increased significantly more in the training group (mean 1.6% [95% CI 0.8-2.4]) than in the control group (0.6% [-0.2 to 1.4], p = 0.006). By contrast, at non-weightbearing sites, such as the distal radius, there was no significant difference between the training and control groups (-1.5% [-2.7 to -0.3] vs -0.7% [-1.9 to -0.5], p = 0.60). In the training group there was a significant improvement in vertical jump and predicted oxygen consumption per min at maximum exercise compared with controls. INTERPRETATION High-impact exercises that load bones with a rapidly rising force profile in versatile movements improve skeletal integrity, muscular performance, and dynamic balance in premenopausal women. If done on a regular basis, this type of exercise may help decrease the risk of osteoporotic fractures in later life. Long-term studies are required to show whether these 18-month results can be translated into long-term benefit.

Effect of a vibration exposure on muscular performance and body balance. Randomized cross-over study

This randomized cross‐over study was designed to investigate the effects of a 4‐min vibration bout on muscle performance and body balance in young, healthy subjects. Sixteen volunteers (eight men, eight women, age 24–33 years) underwent both the 4‐min vibration‐ and sham‐interventions in a randomized order on different days. Six performance tests (stability platform, grip strength, isometric extension strength of lower extremities, tandem‐walk, vertical jump and shuttle run) were performed 10 min before (baseline), and 2 and 60 min after the intervention. The effect of vibration on the surface electromyography (EMG) of soleus, gastrocnemius and vastus lateralis muscles was also investigated. The vibration‐loading, based on a tilting platform, induced a transient (significant at the 2‐min test) 2·5% net benefit in the jump height (P=0·019), 3·2% benefit in the isometric extension strength of lower extremities (P=0·020) and 15·7% improvement in the body balance (P=0·049). In the other 2‐min or in the 60‐min tests, there were no statistically significant differences between the vibration‐ and sham‐interventions. Decreased mean power frequency in EMG of all muscles during the vibration indicated evolving muscle fatigue, while the root mean square voltage of EMG signal increased in calf muscles. We have shown in this study that a single bout of whole body vibration transiently improves muscle performance of lower extremities and body balance in young healthy adults.

Health benefits of cycling: a systematic review

The purpose of this study was to update the evidence on the health benefits of cycling. A systematic review of the literature resulted in 16 cycling‐specific studies. Cross‐sectional and longitudinal studies showed a clear positive relationship between cycling and cardiorespiratory fitness in youths. Prospective observational studies demonstrated a strong inverse relationship between commuter cycling and all‐cause mortality, cancer mortality, and cancer morbidity among middle‐aged to elderly subjects. Intervention studies among working‐age adults indicated consistent improvements in cardiovascular fitness and some improvements in cardiovascular risk factors due to commuting cycling. Six studies showed a consistent positive dose–response gradient between the amount of cycling and the health benefits. Systematic assessment of the quality of the studies showed most of them to be of moderate to high quality. According to standard criteria used primarily for the assessment of clinical studies, the strength of this evidence was strong for fitness benefits, moderate for benefits in cardiovascular risk factors, and inconclusive for all‐cause mortality, coronary heart disease morbidity and mortality, cancer risk, and overweight and obesity. While more intervention research is needed to build a solid knowledge base of the health benefits of cycling, the existing evidence reinforces the current efforts to promote cycling as an important contributor for better population health.

High-impact exercise and bones of growing girls: a 9-month controlled trial.

Abstract: The maximum amount of bone a person can obtain during the first two decades of life is an important determinant of bone mass in later life, and an increase in peak bone mass has been associated with decreased risk for osteoporotic fractures. It is known that growth of bone and thus development of peak bone mass are strongly controlled by genetic factors, but information on the role of environmental factors, such as exercise and nutrition, (e.g., exercise) on growing bone is limited. We tested a hypothesis that in growing girls the benefit of mechanical loading on bone mineral mass and bone strength is better before rather than after the menarche. Sixty-four girls (25 premenarcheal, 39 postmenarcheal) carried out a supervised 9-month step-aerobic program (two sessions per week), each session complemented with additional jumps. Sixty-two girls (33 premenarcheal, 29 postmenarcheal) served as controls. Bone mineral content (BMC) at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). In addition, the cortical density (CoD, mg/cm3) and cortical cross-sectional area (CoA, mm2) and the density-weighted polar section modulus (BSI, mm3) of the tibial midshaft were determined by peripheral quantitative tomography (pQCT). In the premenarcheal girls, BMC increased statistically significantly more in the trainees than controls at the lumbar spine (p= 0.012) (8.6% vs 5.3%) and femoral neck (p= 0.014) (9.3% vs 5.3%). In the tibial midshaft, the intergroup differences (CoD, CoA and BSI) were not significant. The postmenarcheal girls showed no significant post-training intergroup differences in any of the bone parameters (BMC increased in the lumbar spine 6.0% vs 4.9%; femoral neck 3.4% vs 3.2%; and trochanter 2.6% vs 3.5%). Although a large proportion of bone mineral increase in the growing girls of this study was attributable to growth itself, this 9-month exercise intervention showed that a clear and large additional bone gain could be obtained in exercising premenarcheal girls, but not in exercising postmenarcheal girls. In other words, exercise seemed more beneficial for additional bone mineral acquisition before menarche (i.e., during the growth spurt) rather than after it.

Health-enhancing physical activity across European Union countries: the Eurobarometer study

The World Health Organisation (WHO) recommends the development of comparable national physical activity surveillance systems to assess trends within and amongst countries as the Global Strategy for Diet and Physical Activity is implemented. To date, the lack of well-standardised measurement instruments has impeded such efforts, but new methodologies are being developed for this purpose. This paper describes the usefulness of the International Physical Activity Questionnaire (IPAQ) in population samples. The Special Eurobarometer Wave 58.2 2002 covered physical activity and provided a good vehicle for assessment of health-enhancing physical activity (HEPA) in the European Union. Data from around 1,000 individuals in each of the 15 member states were collected after careful translation of the questionnaire. IPAQ scoring protocol version 2 was used for definition of activity categories. Data on the prevalence of sufficient total activity, sedentariness, frequent walking and sitting, in total and by gender across European Union (EU) countries showed consistent patterns. The prevalence of sufficient physical activity for health across the member countries was 29%. It ranged from 44% in the Netherlands to 23% in Sweden. The prevalence of sedentariness across countries was in general the mirror image. Regular walking was most prevalent in Spain. Gender was related to physical activity in that men were 1.6 times more likely than women to be sufficiently active, less likely to be sedentary and slightly more likely to sit for at least 6 hours daily. The findings suggest that two thirds of the adult populations of the European countries are insufficiently active for optimal health benefits. As the IPAQ measurement provides information about the patterns of total physical activity and inactivity, the findings indicate possibilities for targeted health promotion efforts.

Effect of four-month vertical whole body vibration on performance and balance

PURPOSE This randomized controlled study was designed to investigate the effects of a 4-month whole body vibration-intervention on muscle performance and body balance in young, healthy, nonathletic adults. METHODS Fifty-six volunteers (21 men and 35 women, aged 19-38 yr) were randomized to either the vibration group or control group. The vibration-intervention consisted of a 4-month whole body vibration training (4 min.d(-1), 3-5 times a week) employed by standing on a vertically vibrating platform. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway on a stability platform) were performed initially and at 2 and 4 months. RESULTS Four-month vibration intervention induced an 8.5% (95% CI, 3.7-13.5%, P=0.001) net improvement in the jump height. Lower-limb extension strength increased after the 2-month vibration-intervention resulting in a 3.7% (95% CI, 0.3-7.2%, P=0.034) net benefit for the vibration. This benefit, however, diminished by the end of the 4-month intervention. In the grip strength, shuttle run, or balance tests, the vibration-intervention showed no effect. CONCLUSION The 4-month whole body vibration-intervention enhanced jumping power in young adults, suggesting neuromuscular adaptation to the vibration stimulus. On the other hand, the vibration-intervention showed no effect on dynamic or static balance of the subjects. Future studies should focus on comparing the performance-enhancing effects of a whole body vibration to those of conventional resistance training and, as a broader objective, on investigating the possible effects of vibration on structure and strength of bones, and perhaps, incidence of falls of elderly people.

Effects of Unilateral Strength Training and Detraining on Bone Mineral Density and Content in Young Women: A Study of Mechanical Loading and Deloading on Human Bones

This study assessed the effect of unilateral strength training at 80% one repetition maximum and of detraining on bone mineral density (BMD, g/cm-2) and bone mineral content (ΣBMC, g) in young women. Twelve female physiotherapy students trained their left limb by leg press an average of four times per week for 1 year followed by 3 months of detraining. Twelve students served as controls. Repeated bone measurements were performed by dual energy X-ray absorptiometry of the lumbar spine, femoral neck, distal femur, patella, proximal tibia, and calcaneus. The training increased the muscle strength of the trained limb, and the BMD of the same limb showed a nonsignificant but systematic increase in distal femur, patella, and proximal tibia, and in ΣBMC of the five measured limb sites (considered an index of the total osteogenic effectiveness of the training). Simultaneously, the muscle strength increased in the untrained limb as an evidence of cross-training effect. A corresponding small but systematic increase was also seen in BMD of this limb as well as in ΣBMC. After the cessation of training, leg extension strength was retained but BMD and ΣBMC of the trained and untrained limbs declined towards baseline values in 3 months. The BMD and ΣBMC values in the control group showed an increasing tendency during the follow-up but the changes were less than 1%. The differences of the changes in BMD and ΣBMC between the left and right limb in the control group, as well as between the same limb in the training and control groups were nonsignificant. The findings of this study indicate that unidirectional strength training, intensive enough to induce substantial strength gain, is not an effective stimulus to increase BMD and BMC in young, physically active women. The unilateral training model turned out to be feasible in these subjects, producing a definite cross-training effect in muscle strength and a trend of similar effect in BMD. Further development of the unilateral training model, and studies to test if training produces adaptation in nonloaded bones (i.e., a crosstraining effect), are also warranted.

The site-specific effects of long-term unilateral activity on bone mineral density and content

This study assessed the site-specific effects of long-term tennis playing on the bone mineral density (BMD) and content (BMC) of upper extremities in male Finnish top-level players using a dual energy x-ray absorptiometric (DXA) scanner. In players (n = 20), the BMDs and BMCs were significantly higher in each bone of the playing right extremity (p < 0.05-0.001), the side-to-side difference being largest in the humeral shaft (BMD + 25.4%, BMC + 28.7%) and proximal humerus (BMD + 14.4%, BMC + 20.5%), and smallest in the ulnar shaft (BMD + 3.1%, BMC + 7.5%) and distal ulna (BMD + 6.3%, BMC + 7.8%). In sex-, age-, weight-, and height-matched controls (n = 20), the right-to-left differences were small ranging from 0.0% to + 6.4% (average +3%). The number of training sessions per week was the only variable in muscle strength and training history assessment which showed, in several anatomic sites, a significant correlation with the relative bone mineral variables (r = 0.460-0.627, p < 0.05-0.001). In conclusion, long-term unilateral tennis activity had a clearly positive effect on the BMD and BMC of the bones of the playing extremity. The effect was very site-specific, being greatest in the humerus and smallest in the ulna. The effect was always greater in BMC than BMD indicating that the excess mineral was used not only for condensation of the bone tissue, but also for enlargement of bone dimensions.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone mineral density of female athletes in different sports

Anthropometry, training history, cardiorespiratory and muscular performance capacity, and bone mineral density (BMD) were studied in female orienteers (n = 30), cross-country skiers (n = 28), cyclists (n = 29), weight lifters (n = 18) and in a reference group (n = 25). BMD was measured at lumbar spine, femoral neck, distal femur, patella, proximal tibia, calcaneus and distal radius by dual energy X-ray absorptiometry. The weight lifters had significantly higher weight adjusted BMD (P < 0.001) than the referents at all sites (9-26%) except in femoral neck and calcaneus. Of the endurance athletes, the orienteers were the only group which had significantly higher BMD (P < 0.05) than referents, only at distal femur (5%) and proximal tibia (5%). BMD did not differ significantly at any skeletal site between subjects with different calcium intake. Weight training seems to provide more effective osteogenic stimulus than endurance training. The differences in BMD at different sites between the groups were consistent with specificity of the stimulus to the training of the studied sports.