First off, let me state that i love my PacerPoles and have both the 2 section and 3 section poles. They are a marvel of design and manufacturing. Great thought and insight went into their design and top notch manufacturing is utilized in every aspect of them.
However, they are NOT the panacea for every conceivable trekking situation one may find themselves in. Overall, they are exceptional and may be superior to other designs for many, many terrains one will encounter, depending upon where one is hiking.
Bottom line for me: i really like them.
Trekking poles, in any incarnation, including Nordic Poles, offer better balance, and potentially offer the ability to move at a faster pace, or to produce less fatigue of the lower body muscles groups mainly responsible for locomotion by "off-loading" those muscles, thus allowing us to hike longer, or a combination of a bit faster and a bit farther.
The following discussion fully realizes that no matter the technique used, the primary muscles used for locomotion when hiking are those of the lower body. Since this is in common regardless of technique employed, they are being largely "factored out" of the discussion that follows. Again, this doesn't mean that they aren't important, it just means that the arguments regarding them are largely the same regardless of how trekking poles are used - the differences are really minor.
Now for generalized comments i disagree with.
[Note: obviously, it's easy to find some point of disagreement with a somewhat generalized comment by trying to apply it to situations for which it was not originally intended - sort of a erecting 'straw man' to be easily torn down. i'm not trying to do that here - at least i hope i'm not and don't mean to. i just want to show what i believe are the reasonable limits to those generalized statements and to reveal that they aren't a panacea applicable to every situation. the way i read the original Post was that the generalized comments were made to be applied to every (or nearly every) situation. maybe i misread the Post? Hope not.]
[Note: Also, it should be noted that i truly believe that i am using the PacerPoles as they were intended to be used, but perhaps my following comments may reveal a misunderstanding in my use of them and so make my arguments moot and, in fact, totally wrong. I welcome any correction.]
>>"It's generally understood from biomechanics of the body that the pull action is inferior to the push. In practical terms the body performs better when it can push itself along; this has already proved successful in the Review, when moving over ''flat to moderate terrain'', pushing against the handle-contours from behind."
While i can't say that i categorically disagree with the above quote, i can say that it is too generalized. The quoted statement, specifically the first part and not referring to the Reviewer's first-hand experience on more moderate terrain, i would agree with for moderate slopes, but i would NOT AGREE with very steep slopes. Why? The superiority of pulling to pushing depends upon at least two factors: muscles involved and the position of the body when force is exerted.
The reference made in the original Post to biomechanics is just that a reference w/o any substance or detailed explanation. Here is what i'm thinking, and anyone please correct me if you feel that i am mistaken.
When speaking of trekking pole use when ascending a steep slope, the pushing movement relies heavily, upon extending the triceps muscles of the upper arms, with a much slighter movement of other upper body muscle groups. Depending upon arm postion when attempting to climb the steep slope, the Biceps muscles might be required if one is to pull oneself up - this is a weak point of pulling. Relatively speaking both the Tris and Bis are smaller muscles than the Latissimus dorsi and Pectoralis major muscles. The latter two larger muscles would be the main muscle groups involved when climbing a steep ascent if the arms are postioned properly and the arms, together with the trekking poles, are placed in front of the body and then used to PULL the body up the steep incline. This might, depending upon positioning begin with the Bis, but will end with a push involving the Lats, Pects, and Tris. Even here the Tris can get some rest as they are not the only or primary muscles involved as they often are (thought the workload is light) when just using the PacerPoles to push one along the trail.
If one can visualize the callisthenic exercise commonly referred to as the 'Dip', you can see that the three main muscle groups involved in the 'dipping' motion are the Pects, Lats, and Tris. Now, imagine positioning yourself on the dip bars in such a way that you are resting your chest or forearms on the dip bars and then trying to lift your body weight using just your Tris. How many semi-dips/lifts do you think you could perform using just the Tris? In many cases, the answer would be zero. Besides not being up to the task from standpoint of just force, in this example, admittedly, there would also be a very poor mechanical advantage due to the postioning of the arms - this does NOT carry over to the use of the poles to PUSH the body; it is a weak point of my example, but the other points, i believe, hold true. Now admittedly, this is a heavy lift (for the Tris), but the point is that it is a relatively easy movement when all three muscle groups are utilized. My point being, or movements requiring both maximum effort and/or repeated continued efforts, utilizing the larger muscles groups will resort in less fatigue. Also, utilizing these larger muscle groups will be able to off-load the lower body muscles to a greater degree than if the tricps are the main muscles groups utilized.
Engineers and Mathemeticians like to sometimes approach certain problems as what we might term "limit problems" in order to get an idea of the range of values that they might be working with. Let's try and do that here.
What's the steepest slope that we can climb (ignoring negative angles)? It would be a vertical surface. Imagine climbing a peg board in Gym class, or a big wall just pushing yourself up using your Tris. Case closed.
Now my example of 'Dips' ignores the use of the Biceps that are often used in, not in 'Dips', but in pulling oneself up when ascending a steep slope, and so the 'Dips' example was meant to focus on the inferiority of using just the Triceps vs. using the Pects, Lats, and Tris for the ascending steep slopes. The example of climbing the peg board, introduced the use of the Biceps muscles in ascending since they would be needed to pull oneself up a steep slope. Tri's, in most people are larger stronger muscles than the Bi's, but the Bi's aren't used alone in the technique i use, so a simple Tri's vs. Bi's argument doesn't work against the technique i use. In fact, the Tri's are used in the technique i (and most others) employ, just not as heavily as in the PacerPole technique.
In fact, PacerPoles recognizes that on very steep slopes one can't use the arms low and behind Tri's only approach. The design of the PacerPoles includes a ~12in" long section of foam on the upper portion of the straight shaft of the poles just for this purpose!
Also, admittedly, from a cardio standpoint, partially extending the arms in front of us, elevates a portion of our body, perhaps, in some cases, e.g. steep ascents, even above the level of our heart (a "no, no" if we want to keep our HR down), and increases our HR. On very steep ascents we might have no other choice than to do this, if my assessment of kinesiology and biomechanics is correct, but generally it's a bad practice (unless one is trying to give themselves the most demanding cardio workout possible for fitness purposes) and PacerPoles, properly used, are great for keeping the arms low (in other than steep ascents; but then, no pole will keep the arms low on steep ascents, so this is NOT a criticism of PacerPoles).
>>"a result of the arm's leverage being placed out-in-front, in the habitual conventional pole position, which is one of the arm's comparatively LESS efficient angles in relation to raising the body up a slope, stride after stride"
Again, this comment is too all encompassing to be true in all situations - both from the standpoint of Kinesilogy/Biomechanics and from firsthand personal experience.
If i haven't totally led us all (including myself) down the wrong path here (and i don't think that i have missed anything), there comes a point in ascending a slope where it actually becomes beneficial to extend the arms partially (so as to maintain a good mechanical advantage aka 'leverage') in front of us and use the larger muscle groups of the torso to pull us up a steep slope. The angle of the PacerPoles are NOT a hindrance on steep ascents b/c i need to grab the poles lower down on the straight portion of the poles' shafts (just as i would when using any type of pole or staff).
For lesser slopes i have no disagreement with the original Post. I've attempted to use PacerPoles in the proper manner and find them wonderful poles to use (i have both 2 and 3 section poles). Despite their relatively heavy weight which i normally (on flat and slight to at most, in some cases, moderate, slopes) don't even notice, they are very efficient at propelling me along. I truly like them.
When ascending steep slopes, the angle of the poles hinder a bit compared to more mainstream (including Ergo) shaped poles. When ANY grade slope, i, personally (YMMV) find the angle of the PacerPoles useful and not a hindrance.
My firsthand experience on the extremely hilly trails i hike in New England agrees with my limited understanding of Kinesiology and Biomechanics.
In summary: PacerPoles are great, IMHO (YMMV) and very useful. The Post to which i'm responding makes some generalized statements which could have been clarified just a bit, IMHO, which is what i've attempted to do here. Whether i've been successful or not (believe it or not, i've tried to minimize my words here!!!) in these few words, i'll leave it up to those who read them. For any who disagree with my science/pseudo-science (i'll let the reader choose the right word) or my practice, you may fire when ready. Shields Up!!
NOTE: be sure to read all of Dondo's posts and mine to get a better idea of the issues. Apparently, some of my statements are not very clear to some and, hopefully, by reading all of our Posts, what i was attempting to communicate may become clearer.