Maximum values for isometric strength, dynamic strength, and speed of movement (MEV) in the quadriceps muscle were measured in 114 male subjects who were between 11 and 70 yr. Biopsy samples were taken from the quadriceps muscle in 51 of the subjects (22-65 yr. old). Isometric and dynamic strength increased up to the third decade, remained almost constant to the fifth decade, and then decreased with increasing age. However, no measurable external atrophy of the quadriceps muscle, explaining the decline in strength, could be seen in old age. Histochemical changes in the muscle tissue such as decreased proportion of type II fibers and a selective atrophy of type II fibers, were seen with increasing age. The strength decline in old age was also observed to correlate significantly with the type II fiber area. Multiple regression analyses indicated, however, that mechanisms other than the type II fiber atrophy might be responsible for the decline in strength performance during aging. The implications of these findings are discussed.

Where data are to be pooled for international studies, analysis of DIF by culture is essential. Where DIF is observed, adjustments can be made to allow for cultural differences in outcome measurement.

SUMMARYBlood lipids, red cell volume, heart volume, dynamic spirometry, electrocardiograms made at rest and during exercise, and maximal oxygen uptake were determined in 29 former athletes 45 to 70 years old. The subjects had been very successful competitors in endurance events before the age of 30, but for at least 10 years preceding this study had been sedentary.Maximal oxygen uptake averaged 40 ml/kg/min which is 20% higher than that of sedentary middle-aged men but 25% lower than that of still active athletes of the same ages. Vital capacity, forced expiratory volume, and maximal voluntary ventilation showed normal values. Heart volume was large in relation to maximal oxygen uptake and was of the same magnitude as in still active athletes. Red cell volume was also large in relation to maximal oxygen uptake, but normal in relation to the body weight. Cholesterol in serum averaged 260 mg/ 100 ml. Values for neutral fat averaged 1.6 mM, which was higher than that for still active athletes.In the athletes still active, the frequency of S-T changes was as common as in unselected healthy old men but in the former athletes the frequency was reduced. This was also true for the frequency of right bundle-branch block, ST-junction elevation and high T waves. Additional Indexing Words:Maximal oxygen uptake ECG c Heart volume Red cell volume I N A GROUP of well-trained and still competing middle-aged and old athletes, high aerobic work powers (maximal oxygen uptake) and large heart volumes were found.1 This was a highly selected group of men who had trained continuously for at least 20 years and still trained and competed in "orienteering" (cross-country track finding) and skiing.

The reliability of the grip force instrument, Grippit was tested on 51 right-handed women of which 18 were healthy, 19 had rheumatoid arthritis (RA) and 14 had fibromyalgia (FM). Normative data was obtained from 169 healthy subjects. Results indicate that the reliability of Grippit was high in healthy and rheumatoid arthritic women and satisfactory in women with fibromyalgia. All patients showed greatly reduced grip force (RA had on average 21% and FM 40% of the control values) when compared to healthy women. Healthy women had on average 54% of men's grip force. The ratio between average force over 10 seconds and peak force was 73% for RA women, 69% for FM women, 83% for healthy women and 85% for healthy men.

The use of a four‐level questionnaire to assess leisure time physical activity (PA) and its validation is reviewed in this paper. This questionnaire was first published in 1968 and has then been used by more than 600 000 subjects, especially in different population studies in the Nordic countries. A number of modifications to the questionnaire have been published. These are mostly minor changes, such as adding practical examples of activities to illustrate the levels of PA. Some authors have also added duration requirements that were not included for all levels of PA in the original version. The concurrent validity, with respect to aerobic capacity and movement analysis using objective measurements has been shown to be good, as has the predictive validity with respect to various risk factors for health conditions and for morbidity and mortality.