**8.1 Exercise testing versus physical activity recalls**

Actual measurement of aerobic fitness, as opposed to estimating it in some fashion, is usually preferable. There are a variety of reference books available detailing exercise protocols for various health and fitness statuses. The researcher who wants to include

cycling set that progressed in intensity with each event presentation could be incorporated (Carter and Sheih, 2010). Obviously, much pilot work would need to be done to determine the

If actual physical exercise testing is not possible, there is still one other avenue to determine cerebral activation during an exercise task: mental imagery. For example, a sport psychology study investigated motor imagery of the golf swing to determine brain region activation. Using the sensori-motor homunculus map as a guide, Ross et al. (2003) compared the amount of fMRI BOLD response in brain regions related to the golf swing between novice versus expert golfers. It was determined that the greater the golf handicap, the greater the region of activation (greater than 2%) in specific somatatropic regions of interest relevant to golf. The powerpoint presentation can be downloaded from the internet with a search engine. A very recent BOLD fMRI study (Cremers et al., 2011) investigated mental imagery consisting of subjects envisioning themselves either walking, standing, or lying down (block design). Their imagined walking (speed = 2.3 ± 0.4 m/s) was associated with activation in the right dorsolateral prefrontal cortex, posterior parietal lobule, and the left cerebellar hemisphere. Therefore, it might be interesting to conduct an imagery intervention study to determine the acute response to an imagined exercise stress test as well as an imagined chronic response to a

long-term exercise intervention. Studies of this nature have not yet been reported.

with both the science and the targeted subject population in mind.

**8.1 Exercise testing versus physical activity recalls** 

Neuroimaging studies are expensive. Exercise testing and training are expensive. Recruitment drop-outs are expensive. And botched tests are expensive. They are expensive in terms of time, money and patience. Neuroimaging and exercise testing aged individuals bring a unique set of challenges to intervention research. There are the standard safety issues to consider when using a neuroimaging technique or conducting a physical exercise test; but the less obvious issues of comfort and trust sometimes slip by unasked, until it is too late and the subject has dropped out of the study. Therefore, when screening an older individual for an imaging and/or an exercise study, the following question must be asked: can the volunteer complete the testing protocol accurately and in relative comfort? The researcher must ascertain that the older volunteer can hear, see, follow directions, and adhere to the instructions. Volunteers must be able to complete enough of the exercise protocol to get valid physiological baseline data and/or remain motionless and pain free in the MRI scanner anywhere from 15 to 120 minutes. The brief breaks afforded between imaging sequences when a subject is free to move slightly may be insufficient. Arthritis, nasal-sinus drainage, and circulatory issues have thwarted many research MRI scans. For a first-time MRI scan, volunteers may back out at the last minute due to unanticipated fright (hence a simulator is an invaluable resource) or the irrational worry that the MRI will read their minds (thanks to outlandish media stories). Thus, the researcher must design protocols

Actual measurement of aerobic fitness, as opposed to estimating it in some fashion, is usually preferable. There are a variety of reference books available detailing exercise protocols for various health and fitness statuses. The researcher who wants to include

exact power outputs required to elicit measureable BOLD signals.

**7.2 Exercise mental imagery** 

**8. Testing pearls and pitfalls** 

exercise in the research design should obtain the ACSM Guidelines for Exercise Testing and Training (2009). A good textbook is Nieman's (2010) exercise prescription textbook used for training undergraduates in exercise science. However, there are times when it is inconvenient, illogical, or cost-prohibitive to conduct a fitness test. For those times when actual exercise testing is ruled out, there is a rather good non-exercise aerobic fitness estimation equation that is quite easy to use, providing one is trained in obtaining a valid physical activity recall. While it can be difficult to get accurate physical activity recalls beyond a few weeks, a seasoned investigator in physical activity recall questionnaires can elicit excellent responses, even recalls spanning several years.

One physical activity recall formula for estimating aerobic fitness has been in the literature since 1990. It was gathering dust until recently when we used it for a retrospective analysis exploring the role aerobic fitness might have on cerebral white matter integrity on both younger and older adults (Marks et al., 2007). Ever since that publication, we have been getting inquiries about the formula and how to use it. The formula was developed and tested at the Cooper Aerobic Institute in Texas on over 2,000 U.S. Air Force personnel ranging in age from 18 to 70 years. The subject population included males and females, fit and unfit, healthy and unhealthy. The estimated aerobic fitness value (VO2) has a standard error of about 5 ml/kg/min. This formula is very good for cross-sectional, population-based studies when the purpose is to simply categorize one's fitness level. However, the error range is a bit too high and the fitness categorizing a bit too vague for pre-post research designs where VO2 change is a critical factor. For that, VO2 does need to actually be measured. Although the formula tends to underestimate the highly fit and over-estimate the very low fit, all subjects are still able to be categorized accurately into a fitness level (e.g., low fit, average fit, high fit). The estimation formula and its accompanying physical activity rating scale (PARS) are contained in *Table 2* and T*able 3* below:

```
VO2 max ≈ 56.363 – (0.381 * age) + (1.951 * PARS) – (0.754 * BMI) + (gender * 10.987)
 where: Gender: 0 = women; 1 = men 
 BMI = body mass index = weight (kg) / (height in meters2)
 PARS = physical activity rating scale from 0 to 7 (see Table 3)
```
Table 2. Estimated Aerobic Fitness (VO2 max) (Jackson et al., 1990).
