According to this article on cancer.prostate-help.org, the activities
you named can raise the numbers:
"...other events may, and do, influence the PSA level in the blood.
Ejaculation, bike riding, or any manipulation of the prostate, such
as a DRE [digital rectal exam], all have the tendency to raise the
PSA in the blood. Furthermore, there are theories that the time of
day a sample is drawn and the day within a 28 day cycle may affect
the PSA level. Also, inflammation of the prostate (prostatitis) is
also a frequent source of raised PSA."
More on the page:
Since a DRE is part of a routine prostate exam, you should be
assertive and insist that it be done AFTER the PSA test.
The test is best used to discover significant increases of the
levels from past results. A very good page on the pros and cons
surrounding the test's utility is found on the National Cancer
Institute's site. There is considerable controversy over the
value of the test versus the anxiety and the frequently unnecessary
follow up procedures which can result. Facts such as the following
should be considered:
"Most men with an elevated PSA test turn out not to have cancer;
only 25 to 30 percent of men who have a biopsy due to elevated
PSA levels actually have prostate cancer."
Much more on the page:
A much more detailed and scientific article on prostate cancer
detection, PSA testing and more is found on the Life Extension
site, written by Dr. Strum:
Use Ctrl-F to search the page for "ejaculation", without
quotes, and it will take you halfway down the page to a
pertinent discussion with illustrative tables, which leads
into a discussion of the effect of such activities as bike
or motorcycle riding, horseback riding, etc.
Additional information may be found from further exploration
of the links provided above, as well as those resulting from
the Google searches outlined below.
Searches done, via Google:
"PSA test" "bike riding" sex