Search PubMed⌕ Search

Biomedical subjects

P Oja

Publications and source records attributed to P Oja.

At least 73 records · Page 4Linked to original sources
PubMed1996

Health-related fitness test battery for adults: aspects of reliability.

OBJECTIVE: In two studies, the reliability of 3 balance, 2 flexibility, and 4 muscular strength tests proposed as test items were investigated in a health-related fitness (HRF) test battery for adults. DESIGN: Methodological study. SETTING: A health promotion research institute. SUBJECTS: In study A, volunteers (n=42) from two worksites participated. In study B, a population sample (n=510) of 37-to 57-year-old men and women was selected. MAIN OUTCOME MEASURES: Intraclass correlation coefficient of repeated measures was used to assess inter-rater reliability. The degree of measurement error was expressed as the standard error of measurement. The mean difference with 95% confidence intervals between the testing days or test trials was used to assess test-retest or trial-to-trial reproducibility. The coefficient of variation(CV=[SD/mean] x 100%) from day to day was also calculated. RESULTS: The following tests appeared to provide acceptable reliability as methods for field assessment of HRF: standing on one leg with eyes open for balance, side-bending of the trunk for spinal flexibility, modified push-ups for upper body muscular function, and jump and reach and one leg squat for leg muscular function. CONCLUSIONS: This reliability assessment provided useful information on the characteristics of potential test items in a HRF test battery for adults and on the limitations of its practical use. Testers must be properly trained to ensure reliable assessment of HRF of adults.

Adult↗
PubMed1996

Body composition assessment in lean and normal-weight young women.

Using percentage body fat (BF%) from a three-compartment (3C) model (body density from underwater weighing (UWW) and bone-mineral mass from dual-energy X-ray absorptiometry (DXA) as a criterion, we studied the accuracy of UWW, DXA, two skinfold equations, and two bioimpedance (BIA) equations. Thirty-four women (aged 16-20 years) with BF% 13.5-31.1 volunteered. UWW underestimated BF% by -0.5 BF% (95% CI: -1.0; -0.02), whereas DXA overestimated it by 7.3 BF% (95% CI 5.8; 8.8). Skinfolds underestimated and BIA overpredicted BF%. The differences between 3C and UWW, skinfolds (Durnin & Womersley, 1974) and BIA (Deurenberg et al. 1990) were dependent (range of r values: -0.63 to -0.79; P < 0.0001) on BF%, causing an overestimation of lean subjects' (UWW, BIA) or an underestimation of normal-weight subjects' (UWW, skinfolds) BF%. The 3C model and UWW gave comparable body-composition results for healthy young women with BF% of approximately 20-25. Based on a significant mean difference from the 3C model, and a large standard error of the estimate, we do not regard DXA as superior to skinfolds or BIA to assess BF%.

Absorptiometry, Photon↗
PubMed1996

Is long-term maintenance of health-related physical activity possible? An analysis of concepts and evidence.

The phenomenon of maintenance of health-related physical activity is explored through an analysis of the underlying concepts and of the existing empirical evidence. The following targets were used for the analysis: (1) the concept of health-related physical activity, (2) the concept of maintenance, (3) common manifestations of maintenance in everyday living, (4) the promotional and behavioral characteristics of health-related physical activity, (5) the known determinants of free-living physical activity, and (6) intervention trials on physical activity in free-living groups. The analyses revealed the inherent resistance to adoption and maintenance of physical activity, particularly that of high-intensity and program-centered activities, the persistence, however, of many simple everyday routines and habits, the multiple determinants discovered for free-living physical activity and a few empirical demonstrations of the successful promotion of the maintenance of physical activity over a year or two. The promotion of the maintenance of health-related physical activity seems thus a distinct possibility provided that (1) the promotional situation is analyzed thoroughly, (2) the activity is chosen carefully with an emphasis on moderation in intensity and integration into the participant's life-style, (3) multiple promotional contacts are used, and (4) support from the participant's social and physical environment is provided. There is a need for more research on the maintenance of health-related physical activity using the stages of change models, behavior modification principles, self-control concepts, the concept of intrinsic motivation and the Relapse model. The method of analysis used here could apply to other health-related behaviors as well.

Attitude to Health↗
PubMed1995

Effect of starting age of physical activity on bone mass in the dominant arm of tennis and squash players.

OBJECTIVE: To determine in female tennis and squash players the effect of biological age (that is, the starting age of playing relative to the age at menarche) at which tennis or squash playing was started on the difference in bone mineral content between the playing and non-playing arms. DESIGN: Cross-sectional study. SETTING: Finnish tennis and squash federations. PARTICIPANTS: 105 female Finnish national-level players and 50 healthy female controls. MAIN OUTCOME MEASURES: Differences in bone mineral content in playing and nonplaying (dominant to nondominant) arms (proximal humerus, humeral shaft, radial shaft, and distal radius) were compared in the players and controls and among six groups of players. Players were divided into groups according to the biological age (years before or after menarche) at which their playing careers began: more than 5 years before; 3 to 5 years before; 2 to 0 years before; 1 to 5 years after; 6 to 15 years after; and more than 15 years after. RESULTS: Compared with controls (whose mean +/- SD differences in bone mineral content were 4.6% +/- 4.6%, 3.2% +/- 2.3%, 3.2% +/- 3.8%, and 3.9% +/- 4.3% at the previously noted anatomical sites), the players had a significantly (P < 0.001) larger side-to-side difference in every measured site (15.5% +/- 8.4%, 16.2% +/- 9.8%, 8.5% +/- 6.6, and 12.5% +/- 7.1%). Among players, the group differences in bone mineral content were significant (P < 0.001 to P = 0.005), with the group means clearly decreasing with increasing starting biological age of playing. The difference was two to four times greater in the players who had started their playing careers before or at menarche (lowest mean difference in bone mineral content, 10.5% +/- 7.2%; highest difference, 23.5% +/- 7.2%) than in those who started more than 15 years after menarche (lowest difference, 2.4% +/- 4.8%; highest difference, 9.6% +/- 4.9%). Adjustment for potential confounding factors (age and height) did not change these trends. CONCLUSIONS: Bones of the playing extremity clearly benefit from active tennis and squash training, which increases their mineral mass. The benefit of playing is about two times greater if females start playing at or before menarche rather than after it. The minimal level and minimum number of years of activity necessary to produce these results, the extent to which this benefit is sustained after cessation of intensive training, and the degree to which these results can be extended to other forms of physical activity and other bone sites should be studied further.

Age Factors↗
PubMed1995

Bone mineral density in female athletes representing sports with different loading characteristics of the skeleton.

To address the hypothesis that osteogenic effect of physical loading increases with increasing strain rates and peak forces, we examined 59 competitive Finnish female athletes (representing three sports with different skeletal loading characteristics), physically active referents (they reported an average of five various types of exercise sessions per week), and sedentary referents (two sessions per week) using dual energy X-ray absorptiometry. The measured anatomic sites were at the lumbar spine, femoral neck, distal femur, patella, proximal tibia, calcaneus, and distal radius. The athlete group consisted of aerobic dancers (N = 27), squash players (N = 18), and speed skaters (N = 14). The squash players had the highest values for weight-adjusted bone mineral density (BMD) at the lumbar spine (13.8% p < 0.001 as compared with the sedentary reference group), femoral neck (16.8%, p < 0.001), proximal tibia (12.6%, p < 0.001) and calcaneus (18.5%, p < 0.001). Aerobic dancers and speed skaters also had significantly higher BMD values at the loaded sites than the sedentary reference group, the difference ranging from 5.3% to 13.5%. The physically active referents' BMD values did not differ from those of the sedentary referents at any site. The results support the concept that training, including high strain rates in versatile movements and high peak forces, is more effective in bone formation than training with a large number of low-force repetitions.

Adult↗
PubMed1995

Resting metabolic rate and energy intake in female gymnasts, figure-skaters and soccer players.

We examined the hypothesis that lean female athletes, as compared to other female athletes and controls, have a greater deficit between reported energy intake (EI) and estimated energy expenditure (EE), and a reduction in resting energy expenditure adjusted to fat free and fat masses (REEADJ). The subjects were 12 gymnasts and figure-skaters (lean athletes), 12 soccer players (normal-weight athletes) and 10 normal-weight, untrained, controls. Body composition was calculated from a 3-compartment model (underwater weighing and dual energy x-ray absorptiometry). REE was assessed by indirect calorimetry. Physical activity and EI were estimated from 7-day records. EE was calculated using activity records and REE. REEADJ was similar in all groups (p > 0.05). EI was 8.29 (SD 1.84), 7.04 (SD 2.23) and 8.95 (SD 1.68) MJ.d-1 in controls, gymnasts and soccer players, respectively (p = 0.06). In gymnasts, reported EI was 3.19 (SD 2.63) MJ.d-1 lower than estimated EE. EI minus EE in controls was -0.18 (SD 1.80; different from gymnasts, p < 0.01) MJ.d-1, and in soccer players -0.47 (SD 1.89; different from gymnasts, p < 0.05) MJ.d-1. Low reported energy intake in gymnasts might reflect their attitudes on diet and body image.

Adolescent↗
PubMed1994

Osteoporosis in men with a history of tibial fracture.

The long-term effects of bone fractures on bone mineral density (BMD) at various skeletal sites are poorly established, although a serious fracture, such as a tibia fracture, followed by long immobility and disuse may lead to permanently decreased BMD and, through this mechanism, may be a risk factor for osteoporotic fractures in later life. To determine whether such an injury leads to osteoporosis, we measured the areal BMD (g/cm2) from the lumbar spine (L2-4), right distal radius and ulna, and the femoral neck, distal femur, patella, proximal tibia, distal tibia, and calcaneus of both extremities in 14 men with a history of primarily nonunited (finally bone-grafted) shaft fracture of the tibia and 20 men with a history of primary union. For evaluation of the patients' BMD in the spine and distal forearm, 22 age-, weight-, and height-matched normal men were also measured. The average time of immobilization in a long plaster cast was 27 weeks in the former group of patients and 16 weeks in the latter. The measurements were performed an average of 9 years after the fracture using a dual-energy x-ray absorptiometric scanner. Compared with normal men (mean +/- SD = 1.116 +/- 0.160), the spinal BMDs were significantly lower in men with a history of a primary nonunion (0.979 +/- 0.100, -12.3%) and union (1.010 +/- 0.124, -9.5%). In distal radius and distal ulna, there were no significant differences between the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Effects of free mobilization and low- to high-intensity treadmill running on the immobilization-induced bone loss in rats.

After an immobilization period of 3 weeks, the effects of free remobilization (8 weeks) as well as low- and high-intensity treadmill running on the bone mineral content (BMC) and density (BMD) of the hindlimbs of Sprague-Dawley rats (n = 70) were studied using a dual-energy x-ray absorptiometric scanner. In the low-intensity running program, the rats were allowed to move freely in the cage for 1 week, after which they started to run on a treadmill twice a day for 7 weeks. The speed of the treadmill was 20 cm/s, with an uphill inclination of 10 degrees. The running time was gradually increased from 20 minutes per session to 45 minutes per session. In the high-intensity group, the program was similar, with the exception that the speed of the treadmill was 30 cm/s, with an uphill inclination of 30 degrees. Immobilization for 3 weeks produced a significant BMC and BMD loss in the immobilized left femur and tibia (mean loss 9.6%, p < 0.001) but did not affect the right free limbs. Both low- and high-intensity running restored mineral content in the immobilized limb; however, an average 5% difference (p < 0.05) in mineral content of the right and left limb bones persisted. In the running groups, the values for the immobilized left limbs were at the same level or exceeded (range 3.8-11.6%, p < 0.05-0.01) and those of the free right limbs exclusively exceeded (range 5.3-15.9%, p < 0.05-0.01) the corresponding values of the age-matched control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Reduced bone mineral density in men with a previous femur fracture.

This study determined the areal bone mineral density (BMD) from the lumbar spine (L2-4), right distal radius and ulna, and the femoral neck, trochanter area of the femur, distal femur, patella, proximal tibia, and calcaneus of both extremities in 29 men who had a femur shaft fracture 10 years earlier. For evaluation of the patients' BMDs in the spine and distal forearm, 29 age-, weight-, and height-matched normal men were also measured. Compared with normal men (mean +/- SD = 1.123 +/- 0.153), the spinal BMDs of the patients were significantly (p = 0.0054) lower (1.018 +/- 0.119, -9.3%). Distal radius and distal ulna showed no significant group differences. In patients, the mean BMD of the injured extremity (compared with the uninjured side) was significantly lower in the distal femur (-6.8%; p = 0.0000), patella (-5.4%; p = 0.0000), proximal tibia (-4.7%; p = 0.0000), and calcaneus (-2.2%; p = 0.0259). In the proximal femur, this value was at the same level (femoral neck 1.3%, NS) or higher (trochanter area 6.3%, p = 0.0002) than that in the uninjured extremity. The relative BMDs of the injured extremity did not associate with the fracture type, fracture location, age, muscle strength, follow-up time, or non-weight-bearing time but showed significant (r = 0.33-0.64) positive correlation with low pain assessment and high functional scores of the injured extremity.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Long-term unilateral loading and bone mineral density and content in female squash players.

We examined 19 female Finnish national level squash players and 19 healthy female controls with a dual energy x-ray absorptiometric (DXA) scanner for the determination of the association between long-term unilateral activity and bone mineral density (BMD) and content (BMC) of the upper extremities. In players, the BMDs and the BMCs were significantly higher in each bone site of the playing extremity. The side-to-side difference was largest in the proximal humerus (BMD 15.6%, BMC 17.8%) and smallest in the ulnar shaft (BMD 5.6%, BMC 7.3%). In sex-, age-, weight-, and height-matched controls, the side-to-side differences were significantly smaller, ranging from 1.6% to 4.1%. The number of training years and elbow flexion strength correlated positively with the relative BMD and BMC in the humerus of the playing arm (r = 0.632-0.685). The starting age of training in turn correlated negatively (r = -0.483 to -0.577) with these bone parameters. Significantly larger side-to-side differences (average 22%) were found in players who had started their career before or during menarche than in those who had begun the training 1 year or more after the menarche (9%). These findings suggest that the bones of the playing extremity clearly benefit from active squash playing. The benefit is largest in humerus and smaller in the bone of the forearm. The benefit of playing is stronger if the athlete has started the training at or before menarche than after it.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Dual energy X-ray absorptiometry is also an accurate and precise method to measure the dimensions of human long bones.

The accuracy, as well as the in vitro and in vivo precision of width and length measurements of human humerus and femur from dual energy X-ray absorptiometry (DXA) images, was investigated. The measurement was based on the bone area inside a specified region determined by the bone edge detection software of the scanner. The accuracy and in vitro precision studies were performed using a bone-simulating aluminum phantom embedded in different amounts of water. The in vivo precision was determined by measuring both limbs twice in 10 subjects (for humerus) and in 9 subjects (for femur). The accuracy was not significantly affected by the amount of water, and varied from 0.6 to 1.2%. Similarly, the in vitro precision varied from 0.4 to 0.6%. The average in vivo precision of the width measurement ranged from 0.4% (humeral and femoral midshaft) to 0.9% (proximal humerus), not depending on the size of the measured bone. The precision of the length measurement was 0.3% for the humerus and 3.7% for the femoral neck. In conclusion, the standard DXA technique provides a reliable measurement of the width and length in human humerus and femur in vivo, and thus may be useful in evaluating the properties of these bones in conjunction with the standard bone mineral measurements. Specifically, studies evaluating the effects of various types of mechanical loading (exercise) on bone may greatly benefit from this possibility because not only the bone mineral content and density but also the bone geometry change due to loading.

Absorptiometry, Photon↗
PubMed1994

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 (sigma BMC, 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 sigma BMC 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 sigma BMC. After the cessation of training, leg extension strength was retained but BMD and sigma BMC of the trained and untrained limbs declined towards baseline values in 3 months. The BMD and sigma BMC 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 sigma BMC 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Reproducibility of computer measurement of maximal isometric strength and electromyography in sedentary middle-aged women.

The objectives of this study were (i) to determine the reproducibility of computer measurements of isometric strength and related electromyography in several muscle groups in sedentary middle-aged women, (ii) to evaluate the effects of different digital signal averaging methods on the reproducibility, (iii) to determine the final test score to be preferred in terms of improved reproducibility of isometric strength measurements, and (iv) to evaluate potential advantages provided by the computer measurement. Fifteen subjects were measured three times within a 2-week period. The measurements consisted of recordings of maximal isometric strength and rate of force production during trunk extension and flexion, leg extension and dominant forearm flexion with simultaneous recordings of surface electromyography, except in the trunk flexors. The following four final test scores were determined for each trial: the maximum of the three scores, the mean of the two highest scores, the median of the three scores and the mean of the three scores. The scores for the strength measurement were generally more reproducible (coefficient of variation, CV, approximately 6% and intraclass correlation coefficient ICCC, approximately 0.90) than those of the other measurements (CV > 10%, ICCC 0.13-0.97). There was no obvious preference for any type of final test score or for the width of the averaging window in the computer analysis. For isometric strength the reproducibility of the computer measurements was comparable to that of the voltmeter assessments. Computer analysis seems to be a versatile method for determining parameters of neuromuscular performance with reasonable reproducibility.

Computers↗
PubMed1994

Cardiovascular effects of Atenolol, scopolamine and their combination on healthy men in Finnish sauna baths.

Indicators of cardiovascular strain were studied in 12 healthy young men under the influence of drugs affecting the autonomic nervous system during the course of taking a sauna bath. There were four bath sessions: one without a drug (control) and three with drug pretreatment (Atenolol 50 mg or Scopolamine 0.3 mg or their combination taken orally 2 h before the bath). The time spent in the hot room depended on the subjective rating of heat stress. Its mean duration at a temperature of 88 degrees C (dry bulb) was 22 (range 14-33) min and did not differ significantly among the sessions. In the Atenolol experiment the mean resting heart rate before the bath was significantly lower (P < 0.001, ANOVA of repeated measures) than in the other experiments. The increase in heart rate per minute of heat exposure was significantly lower (P < 0.001) in the Atenolol experiment and higher (P = 0.017) in the Scopolamine experiment than in the other experiments. The systolic blood pressure increased more slowly (P = 0.004) and the diastolic pressure decreased less (P = 0.02) in the Atenolol experiment than in the other experiments. Heart rate and blood pressure returned to their initial levels during the 30-min recovery after the heat exposure. The plasma noradrenaline concentrations increased approximately twofold during all of the bath sessions, whereas the plasma adrenaline and serum thromboxane B2 concentrations showed no consistent alterations. A small oral dose of Scopolamine alone or in combination with Atenolol produced no marked cardiovascular strain in healthy men during a sauna bath.

Administration, Oral↗
PubMed1994

Walking at work and bone mineral density of premenopausal women.

The objective of this cross-sectional study was to determine whether habitual physical activity such as daily walking at work affects bone mineral density (BMD) in healthy premenopausal women. Thirty-one letter or newspaper carriers and 30 sedentary (non-exercising) office workers were screened out from 167 subjects working in the public post office and a private newspaper publishing company. BMD was measured with a dual-energy X-ray densitometer at the lumbar spine (L2-4), femoral neck, distal femur, patella, proximal tibia, calcaneus and distal radius. In addition, maximal isometric strength, cardiorespiratory fitness, anthropometry, 4-day dietary record and daily occupational work load were assessed. During one work shift the carriers' mean walking distance was 5926 m, with 68 flights of stairs walked, and their mean heart rate was 105 beats/min (114 beats/min during the delivery). The corresponding figures for the office workers were significantly lower: 1895 m, 10 flights and 82 beats/min, respectively. Neither the BMD values adjusted for body mass index (kg/m2) and calcium intake nor the indices of physical performance capacity showed significant differences between the groups. Consequently, habitual daily walking and stair climbing by healthy premenopausal women appeared to be insufficient exercise stimulus to increase considerably the BMD or aerobic and muscular fitness above the values found in a comparable group of sedentary office workers.

Absorptiometry, Photon↗
PubMed1994

Scanner-induced variability and quality assurance in longitudinal dual-energy x-ray absorptiometry measurements.

Characteristics of typical malfunctions and scanner-induced variability observed in dual-energy x-ray absorptiometry (DXA), and their potential effects on longitudinal reliability of DXA were evaluated. According to extensive, cumulative quality assurance (QA) data obtained from two successive x-ray sources during a 3-yr period, the scanner-induced variability may derive from long-term drift (approximately 0.5%/year), short-term drift (approximately 0.2%-2.2%/day), inhomogeneity of the x-ray beam intensity over the tabletop (approximately 1%), and changes in internal filtration (approximately 0.5%). The absolute magnitudes of these effects may be considerable with respect to expected small changes in bone characteristics observed in intervention studies. Furthermore, these effects may not be discriminated from each other. Therefore it may not be possible to correct their cumulative effect using long-term QA data only. The observed drifts are fortunately negligible with respect to the precision adequate for clinical decision making. In contrast, the evaluation of these multiform scanner-induced variability is warranted in longitudinal intervention studies using DXA. It is emphasized that this study was performed with a single DXA system, and the results should be considered accordingly; nevertheless, it is believed that the issues raised would apply to other systems too, at least in the sense of stringent QA. In this respect, single daily phantom measurement appeared to be occasionally ineffective, whereas a remeasurement of the phantom after subject measurements significantly improved the effectiveness of QA. Altogether, the QA procedures, which consider both the short-term and long-term variability as well as the spatial variability over the tabletop, may provide a more effective method to detect silently degrading scanner performance and evaluate its effects on the subject measurements. High-quality operator performance is, however, a prerequisite for proper QA in any setting.

Absorptiometry, Photon↗
PubMed1994

Physically active commuting to work--testing its potential for exercise promotion.

Physical activity has considerable health-enhancing potential. It will be realized, however, only if large number of people participate in adequate activity. This summary report describes the main results of four studies aimed to find out whether physically active commuting to work (PACW) meets the requirements of health and fitness enhancing activity. Three successive mail inquiries (N = 2014) indicated that PACW provided habitual exercise to one-third of employed urban population, and that more than one-fifth expressed willingness and being able to increase PACW. A randomized controlled trial on 68 inactive middle-aged men and women revealed that PACW (1 h daily for 10 wk) increased VO2max by 4.5% (P = 0.02), maximal treadmill time by 10.3% (P = 0.0007), and HDL cholesterol by 5% (P = 0.06). A demonstration project in a large industrial plant showed that PACW can be successfully promoted by low cost measures. In conclusion, these studies suggest that PACW may offer substantial potential as health and fitness enhancing measure provided that it can be practiced safely.

Bicycling↗