[R] Package XML: Parse Garmin *.tcx file problems

[Folkes, Michael]

I'm struggling with package XML to parse a Garmin file (named *.tcx).
I wonder if it's form is incomplete, but appreciably reluctant to paste
even a shortened version.
The output below shows I can get nodes, but an attempt at value of a
single node comes up empty (even though there is data there.  

One question: Has anybody succeeded parsing Garmin .tcx (xml) files?
Thanks!
Michael
_______________________

>doc2 = xmlRoot(xmlTreeParse("HR.reduced3.tcx",useInternalNodes = TRUE))
>xpathApply(doc2, "//*", xmlName)
[[1]]
[1] "TrainingCenterDatabase"

[[2]]
[1] "Activities"

[[3]]
[1] "Activity"

[[4]]
[1] "Id"

[[5]]
[1] "Lap"

[[6]]
[1] "TotalTimeSeconds"


> xpathApply(doc2, "//TotalTimeSeconds", xmlValue)
list()
>