sheer volume 在这句话中什么意思

But I soon became struck by was the sheer volume of both observation and investigation he has done in many different sports and I felt persuaded that what he had to say would be of real interest.

1、翻译这句话

2、sheer volume 在这里的意思？有其他的意思吗？

雅思听力里面的！　Tapescripts：

　　My topic is handedness - whether in different sports it is better to be left- or right-sided or whether a more balanced approach is more successful. I'm left-handed myself and I actually didn't see any relevance to my own life when I happened to start reading an article by a sports psychologist called Peter Matthews. He spent the first part of the article talking about handedness in music instead of sport, which I have to say almost put me off from reading further. But what I soon became struck by was the sheer volume of both observation and investigation he had done in many different sports and I felt persuaded that what he had to say would be of real interest. I think Matthews' findings will be beneficial, not so much in...

　　这边作者先介绍了一下自己的情况，也就是"left-handed"，这里和选项A比较相近，但是此时并没有读出题干来，因此我们完全可以排除A这个答案。（根据我们上面提到的顺序原则）接下来，作者提到了"Peter Matthews"这个人，并且提到了music，也就是和B很相近，此时他的态度是"almost put me off"，这个和题干中的"of value"矛盾，也就是这个也不是答案。此时我们已经可以很顺利的选到正确答案C了。——将错误的信息全部排除，剩下的就一定是正确的答案。

　　当然此题可以通过同义词互换做出来，也就是这边标注了答案的地方:"sheer volume"和C选项中的"impressive size"是类似的意思。但是很多同学会发现，这个词比较难听懂。也就无法很快的找到答案了。