biomechanical details
A good backpack is a wonderful tool. However, because the entire load is positioned behind your back, carrying a heavy load in a backpack has several undesirable biomechanical effects:
- A backpack alters your natural center of gravity.
- A backpack exerts a rearward force on your shoulders.
- A backpack exerts a downward force on your shoulders.
1. A backpack alters your natural center of gravity. When you stand in a natural upright position (without a carried load), your body’s center of gravity is balanced above the middle of your feet. When you carry a loaded backpack, a new center of gravity is created behind your natural center of gravity. You must lean forward to balance the new center of gravity over the center of your feet. The heavier the load, the more you must lean forward to maintain balance. This unnatural body posture results in increased muscle tension from your torso to your toes, diminished agility, and wasted energy.
2. A backpack exerts a rearward force on your shoulders. What do you think would happen if you put a heavy backpack on your back, adjusted everything properly, and then cut through both shoulder straps with a pair of scissors? It is easy to visualize that the upper region of the pack would instantly rotate away from your shoulders and fall toward the ground. The reason your backpack does not do this on the trail is that you are constantly opposing the rearward rotational force of the backpack by pressing your shoulders forward into the shoulder straps. When you carry a loaded backpack, you are performing a non-stop abdominal crunch against the rearward pull of the shoulder straps. Because of the geometry involved, the “crunch” effect is worse for people with shorter torsos, like many women and children.
3. A backpack exerts a downward force on your shoulders. When you carry weight on your shoulders, the weight is supported by your upper torso muscles and your spine, which are relatively weak and vulnerable to injury in comparison with your hips. It is therefore preferable to carry a heavy load on the hips, not the shoulders. When properly fitted and adjusted, a high-quality backpack places most of the weight on the hips, and only a small portion of the load is carried upon the shoulders. However, even a relatively small amount of weight carried on the shoulders can cause soreness in the neck, shoulders, or back after a long day on the trail.
The syncpack Solution:
The syncpack frontpack system offers dramatic biomechanical advantages.
- The syncpack system restores your natural center of gravity.
- The syncpack system cancels out the rearward force on your shoulders.
- The syncpack system eliminates the downward force on your shoulders.
1. The syncpack system restores your natural center of gravity. When you re-position a portion of your load from a backpack to the syncpack front pack, your loaded center of gravity is moved forward to your natural center of gravity. This allows you to stand and walk in a natural upright position, minimizing muscle tension and wasted energy throughout your body. Because of the geometry of the syncpack, carrying approximately 20%-25% of the total load in the syncpack system will restore your natural center of gravity and give you an incredible balanced feeling.
2. The syncpack system cancels out the rearward force on your shoulders. In the same way that a backpack wants to rotate backwards away from your shoulders, the syncpack generates a rotational force forward to counter-balance the backpack. When the syncpack system is properly loaded – with approximately 20%-25% of the total weight in front – the forward pull of the syncpack frame exactly cancels out the rearward pull of the backpack shoulder straps. Your abdominal muscles can quit the non-stop crunch. What a relief!
3. The syncpack system eliminates the downward force on your shoulders. The telescopic elements of the syncpack frame prevent any weight from hanging on your shoulder straps. The frame transmits 100% of the front-carried weight downward to your hips. In addition, because the syncpack counterbalances the load on your back, you can loosen the shoulder straps and take away the downward load on your shoulders. With your shoulder straps slightly loosened and no horizontal or vertical forces on your shoulders, the load is carried 100% on your hips. (When running or traveling or over rough terrain, you may want to snug down your shoulder straps to maximize load stability. This will cause some of the weight of the backpack to be carried on your shoulders again, but you will still have all of the other advantages of the syncpack frame.)
The syncpack Challenge:
Purchase the system securely on-line with our our unconditional money-back guarantee. Load up your backpack and experiment with moving weight forward and back again. Pay close attention to the stresses and strains on your body as discussed above. If you do not agree that the syncpack system makes a heavy load feel dramatically lighter and more comfortable, then take advantage of our unconditional money-back guarantee and return the product for a full refund. What have you got to lose? What have you got to gain?
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