Gold''s Gym: 36" Circuit Trainer Mini Trampoline

I purchased it last week for the sole purpose of sprint interval training, in order to augment the range of hip flexion that I shall continue to get from sprinting on a treadmill. This mini-trampoline has a 36½" O.D. round tubular frame, a 30½" dia web, and (30) stretch-elastic straps. In comparison, I already owned a ''BodyFit by Sports Authority'' mini-trampoline (discontinued), which has a 47" O.D. square tubular frame, a 38" dia web, and (38) steel coil springs.

You must understand the HUGE difference between a larger diameter, more robust design utilizing steel coil springs and a smaller diameter, flimsy design relying on stretch-elastic straps. The former provides far greater rebound, far greater load capacity, and far greater life than the latter. So why would I ever want a smaller, flimsier piece of equipment than I already own? My exercise sessions occur in my basement, where headroom is quite limited. So I use a trampoline for sprinting only, because trampoline sprinting does not require ceiling height much greater than my standing height. Furthermore, for sprinting, you really don''t need or want much in the way of rebound. What you really want for sprinting is shock absorption, plus just enough elasticity to restore the soles of your feet to frame level. Those two trampoline reactions must sync with your "running" movements, which requires damping. During trampoline "running" your leg muscles provide most of that damping, which is unneeded during true, natural running. But this product''s elastomer-bearing straps relieve some of that burden by molecularly providing a small degree of damping. Conversely any trampoline utilizing steel coil springs will lack such damping capacity. So sprinting on this unit feels remarkably smoother than sprinting on a larger unit having coil springs. Also, stretch-elastic straps are silent, whereas metal springs are noisy. I despise the monotony of any mechanical sound that syncs with the rythym of my exercise, which is all too common in fitness equipment. Not a problem with this little gem!

Keep in mind than any exercise that entails rebounding is an aerobic exercise. This is evident in the many rebounding video clips available on YouTube, which show lecturing demonstrators. So if you wish to do a workout of greater cardio-respiratory intensity (causing continuous speech to be impossible), you must do something else. On ANY trampoline, that something else must be an exercise that emulates running, not rebounding. For demonstration of trampoline sprinting see video at You Tube: How To Do Fat Killer Cardio On A Trampoline

So don''t get the wrong idea from my review that larger models having steel coil springs are generally unsatisfactory for "running". They all should work reasonably well for "running", but unless you weigh more than 300 lbs, that expectation should be inferior to this unit; from the standpoints of both biomechanics and noise abatement.

I briefly bounced on it, and found it to have such minimal rebound as to be USELESS for any of those fun exercises that most ordinary users want mini-trampolines for. With only a slight hop, my 185 lb gross weight causes it to "bottom out". Not only does that result in an undesirable shock load to my knees and spine, but it doesn''t produce enough rebound to do anything other than jumping jacks. I imagine that a 100 lb user could do much better in this regard. However, I won''t even try continuing to bounce on it even for jumping jacks, as such abuse would certainly cause the (maxed out) stretch-elastic straps to fail in short order.

While on the subject of its stretch-elastic strap life I want to stress (pun) that this unit should always be kept folded while not in use. The reason why is because when elastomers are kept under constant tension, it GREATLY accelerates their aging. Fortunately though this mini-trampoline is so small that folding/unfolding is a snap for even the weakest users. It''s easier to fold/unfold the frame than it is to insert/remove its two locking pins. Despite its warning labels, it''s unfolded position is so solidly detented (like a toggle clamp) as to be more than adequate for sprinting purposes if the safety pins are left out.

I observed that when I sprint on it where it''s on a concrete floor, it tends to move laterally away from the original spot where it was placed. So I solved that problem by applying 100% silicone sealant onto the bottoms of its (6) feet in order to increase friction.

Electronic Console

It''s a nifty gadget that works quite well when bouncing, but fails to register when sprinting because the web deflections are too small for its sensor''s mechanical pickup arm. Its digital display is a bit too small to read if you want to check your elapsed time without pausing your exercise. Moreover, the console is apt to become damaged when frequently unfolding the frame. Considering those aspects, and that I already use a large digital displaying kitchen timer during exercise, I uninstalled the console and its mounting bracket.

Dual Elastic Resistance Tubes

I wasn''t the least bit interested in this feature when I bought this product... But guess what? I now plan to continue using it for rapid 30 sec intervals of what TheraBand (maker of such elastic tubes) calls "shoulder diagonal D2 flexion". Its a challenging exercise that took 3 days for my sorely neglected deltoid muscles to recover from.

Summary

I realized that it shouldn''t be compared against other mini-trampolines priced up to 10x as much. Otherwise, that would be tantamount to comparing a good low-budget movie to a large-budget blockbuster.

For rebounding, I estimate its maximum load rating to be only about 100 lbs, because the elastic elongation of its 30 stretch-elastic straps is quite minimal. Thus, it could be considered a very cost effective rebounder for children. For "running" (a function that it really excels at; probably better than any other trampoline), I recommend this unit for all users up to 300 lbs. Just remember to fold it after each use, so that you get maximum life out of its 30 stretch-elastic straps. And you can make that minor chore easier on yourself by leaving out its 2 safety locking pins, which are superfluous for "running".