The application of physical activity (PA) questionnaires is the most widely used method for the assessment of PA in population studies (LaPorte et al., 1984), and according to Lagerros and Lagiou (2007), questionnaires are the "method of choice in large epidemiological studies".
In 1997, the scientific Journal Medicine & Science in Sports and Exercise devoted a supplement to more than 30 different instruments for self-reported PA (Pereira et al., 1997). A large number of different questionnaires assessing physical activity are obtainable (Mader et al., 2006, Pereira et al., 1997, Terwee et al., 2010) and new tools continuously appear as a result of the growing interest on PA (Lagerros and Lagiou, 2007). However, "... most likely due to the fact that physical activity is a complex exposure to measure" no PA questionnaire can be adequate for every situation and every population (Lagerros and Lagiou, 2007). Terwee et al. (2010) state that many questionnaires are poorly designed and the content and measurement properties are often either unsatisfying, not tested or reported incompletely and the choice of an appropriate questionnaire for a specific task may be difficult (Kriska and Caspersen, 1997; Terwee et al., 2010).
According to Casperson et al., (1985) PA includes "... any bodily movement produced by skeletal muscles that results in energy expenditure". Nevertheless, only few studies up to now have focused on all components of PA (Kriska and Caspersen, 1997; Terwee et al., 2010), such as sports, transport, occupational physical activity, homework and gardening. The most frequently used German PA questionnaires are the Freiburger Fragebogen zur korperlichen Aktivitat (Frey et al., 1999) and the German version of the IPAQ (International Physical Activity Questionnaire, Booth, 2000). However, these instruments only assess recent PA and also include open questions; hence automatic processing and the use in large epidemiologic studies may be difficult.
There are only few questionnaires (Cumming and Klineberg, 1994; Friedenreich et al., 1998; Kriska et al., 1988; 1990) that aim to assess lifetime PA (Chasan-Taber et al., 2002). All of them are designed to be interviewer administered, "... a technique often not practical for epidemiologic studies conducted among large numbers of participants" (Chasan-Taber et al., 2002).
There are numerous studies on the relationship between PA and health and there is solid evidence that PA can reduce the risk of developing non-communicable diseases, like cardiovascular diseases, breast, colon and other forms of cancer, type-2 diabetes etc. (Pedersen and Saltin, 2006), and PA can also increase life expectancy (Blair et al., 1996; Kohl, 2001; Lee et al., 2012; Wannamethee and Shaper, 2002). Further, PA also plays an important role in therapy and in rehabilitation of non-communicable diseases (Doyle et al., 2006, Schmitz et al., 2010).
In a recent study (Wen et al., 2011) a multiple choice questionnaire (three questions measuring PA during the previous month) showed that even low-volume PA (15 min per day) was associated with a 14% risk reduction of all-cause mortality and a 3 year longer life expectancy. Application of a questionnaire capable of assessing PA over the whole life might increase the benefits of such a study or related ones substantially because the development of non-communicable diseases is a long-term process which cannot be mapped by means of a questionnaire assessing only recent PA.
For detailed investigations of the effects of PA patterns on non-communicable disease prevention and therapy, a questionnaire fulfilling the demands summarized in Table 1 is a substantial extension which enables to assess the role of the life-time distribution of PA for preventing or reducing the development of non-communicable diseases. As no existing questionnaire fulfills these demands, we decided to design a reliable and valid questionnaire that can be used for all groups: athletes, healthy people, and also for groups of patients, e.g. cancer patients. We considered assessment of PA over a short and long time period as was suggested by Kriska and Caspersen (1997) in order to obtain the best estimate of PA levels throughout life.
The possibility to distinguish between different types of PA (endurance, transport, speed, strength) a person has carried out in the past can be important for various reasons: (a) to get to know the prevalence of different types of PA of a person and (b) differences in PA patterns between individuals or groups, or (c) to monitor changes of PA patterns after certain training interventions. Furthermore, such a questionnaire can be used to investigate health benefits with respect to different types of bodily training (Bouchard, 2001; van Poppel et al., 2010) and thereby public health recommendations may be improved (Lagerros and Lagiou, 2007): for example, it is still unclear whether there are special types of PA that reduce e.g. cancer risk more than others: "To date, there is no suggestion that one type of physical activity provides greater benefit than another" (Wolin and Tuchman, 2011) and "... the precise exercise prescription, in relation to type, intensity, duration and frequency needed for cancer protection remains unknown" (McTiernan, 2003).
The physical activity biography
Several considerations and pilot studies preceded the questionnaire described below in order to eliminate or reduce possible problems as early as possible. The PAB measures a person's amount of PA from childhood on throughout life. In the PAB the amount of sport activities (endurance with low intensity, medium intensity, and high intensity; sports with high impact of speed and/or strength) and locomotion by bike or by foot (transport) are assessed. In order to make clear what is meant by low, moderate and high intensity, the information given in Table 2 was provided for the participants. The questions are related to different time domains (previous three years, previous three weeks and during one's childhood/youth, between the age of 20 and 40 years, between the age of 40 and 60 years and above the age of 60 years). The participants are asked to answer the questions on a 5point rating scale (0-4), at which the graduation indicates the amount of hours a certain type of activity has been performed per week (Table 3).
The PAB was evaluated by analyzing normal distribution, item difficulty, retest-reliability of one month, and factor analysis. There is a strong relationship between PA and physical fitness (Blair et al., 2001), in particular between current fitness and recent physical activity, and therefore construct validity was tested by means of a correlation analysis between the item responses in the PAB and the results of physical fitness tests and, in addition, with another questionnaire (FFB-mot) testing self-assessed fitness.
The PAB was evaluated by testing three different samples (altogether 141 participants). The characteristics of these samples are depicted in Table 4 in which also the applied quality criteria tests are indicated. Sample A consisted of 33 healthy men and 22 healthy women (59 people were tested, 4 very old ones were excluded because of a large age gap to all others). The participants have not been participating in any sports competitions at a higher level and also were not currently studying exercise science or physical education. They received a free folder including all of their test results and an individual rating of their physical fitness status. Sample B consisted of exercise science or physical education students and sample C were budding students, who just passed the entry tests for the exercise science or physical education program at the local University.
Questionnaires: Three questionnaires were used in this study. One questionnaire included questions concerning demographical data and medical history. The second one was the new self-assessment questionnaire PAB (Physical Activity Biography). The third questionnaire, the Physical Fitness Questionnaire (Bos et al., 2002) (Fragebogen zur Erfassung des motorischen Funktionszustandes, FFB-Mot) deals with current physical fitness and contains 24 items and 4 scales: Strength, Endurance, Flexibility, and Coordination. The participants were asked how problematic conducting a certain PA would be for them. The rating scale ranges from 1 (I cannot do this activity) to 5 (I have no problems).
Exercise tests: In addition to the FFB-Mot questionnaire, physical fitness was also assessed by means of exercise tests in sample A:
Endurance was tested on a cycle ergometer using a stepwise increase of load every minute according to Hofmann and Tschakert (2011) in which heart rate, ECG, lactate, and spirometric data and Lactate Turn Points 1 and 2 were determined. For the analysis of construct validity, obtained values (in respect of body weight) for V[O.sub.2max] (V[O.sub.2max,rel]) and for maximum power ([P.sub.max,rel]) were used.
Flexibility of the muscle groups: m. erector spinae, m. rectus femoris, m. trapecius, m. triceps surae, m. pectoralis, mm. adductores, mm. ischiocruales, m. iliopsoas were tested using standard flexibility tests (modified from Janda, 1979, 1994). Both sides were tested separately and a three-point rating scale (1 ... far beneath normal range; 2 ... beneath normal range; 3 ... within normal range) was used. The scores of the eight muscle groups and the two sides were summed up, thus the flexibility scores ranged from 16 to 48. A higher score indicates a better flexibility.
Balance was determined using four simple tests. The participants were asked to stand still in certain positions for at least 10 seconds. While standing in those positions they were not allowed to jump or move their foot or feet. Prior to every exercise, the participants had one minute to practice each task. Every exercise was tested first with both feet...