SUMMER SCIENCE FRIDAY: WEIGHTED VESTS

Equipment. Taken by PKSenagore July 9, 2018. All rights reserved.

“READ THIS BEFORE WALKING WITH WEIGHTS” suggests Ashley Lauretta in an article for Under Armor’s MyFitnessPal.com blog.  In it, several experts ‘weigh-in’ on the subject. Most do NOT recommend using hand, wrist, or ankle weights to build strength while exercising.  The physics involved in adding weight to the peripheral limbs translates to added “torque” on the proximal joints; which increases the stress placed on ankle and wrists.
  
The referenced trainers and coaches DO recommend walking faster and using hill repeats to boost the physical effort performed during walk workouts. High Intensity Interval Training walking has been discussed on previous Earned Runs posts, and is the basis for the 2018 SUMMER CHALLENGE IV: SERIES SWEEP. Adding resistance training is also recommended. 

Scientific research suggests there may be some performance benefits to running, walking, or exercising while wearing a weighted vest, and although some might be helped, there are reasons to be cautious before putting on this piece of equipment. A livestrong.com piece, “Is Wearing a Weighted Vest Bad for Your Back”, by Patrick Dale, discusses one downside, spinal compression.  He suggests that high impact activities like running and jumping moves should be avoided.  Similar advice could apply to those who wish to lessen the effect of the extra load on knees and ankles.

All persons wearing a weighted vest should be aware, says Dale, that doing so alters the body’s center of gravity, and that uneven loads (all on front or all on back for example) will unevenly stress muscles of the body’s back or front respectively. Thus, his suggestion is to equally distribute the added weight, front to back and laterally (right to left). The weight also should be closely secured such that it doesn’t shift or fall away from the body with movement.  
 
With all the information pointing to the increased risk of injury associated with weighted vest wearing, what might be the advantages? The Dale article points out that persons involved in occupations requiring heavy load lifting must train for these activities, like the military, law enforcement officers, and firefighters, who routinely exercise with weighted vests.  Surprisingly, scientific work suggest those who may perhaps be the weakest and most out-of-shape might also benefit from “wearable resistance training.”  
 
One study showed that a 5-year program with 18 older women participants (9 in the training group and 9 in the control group), which involved the wearing of a weighted vest plus jumping exercises, helped maintain hip bone mass in the training group women, and that it promoted “long term adherence and compliance” with training that might ultimately prevent fracture. 
 
Another 22-week study demonstrated that older obese adults who wore weighted vests for a goal of 10 hours of each day (during their most active hours, with total weight worn not more than 15% of their baseline body weight) as part of a weight loss program experienced slightly less bone mineral density (BMD) loss than dieters who did not.
 
A small, 6-week pilot study of 15 postmenopausal women with sarcopenia (low lean muscle mass), involved the wearing of weighted vests during two exercise sessions per week. Seven participants in the training group (there were 8 controls who did not train) performed 8 sets, 3 repetitions each, of 5 exercises, while wearing the vests (front and side lunges, squats, calf and toe raises). There was a 15 second rest between each set. The training group showed improvement in pelvis BMD and knee extensor strength.
 
On the other hand, no benefit to BMD, quad strength, balance, or walking stability (among other measures) was seen when women with osteopenia and a previous wrist fracture, who were considered to be at risk of future fracture, wore weighted vests and completed a 6-month strength exercise program. 
 
As is true with medical research results in which study design and methods vary, it is difficult to say with certainty exactly which groups would benefit from training with weighted vests, exactly which exercise protocol would provide the most benefit, and exactly the degree of benefit that would be experienced.
 
However, these few small studies suggest that, safely worn, weighted vests might assist people who cannot vigorously train (walk fast or perform hill repeats for example) to boost their exercise efforts above what could be attained minus the vests.  And the increase in an evenly distributed load may help maintain or possibly build bone and muscle strength. 
 
Pilot studies that are successful in detecting a small but significant trend toward improvement are likely to lead to larger more definitive studies that explore an issue more completely.  Hopefully this will be true in the case of wearable resistance training.  If buckling/strapping on a weighted vest is shown to help counteract the negative effects of sitting or can take the place of conventional lifting exercises, what a time-saving health boost it would be for many!
 
In the meantime, care should be taken to avoid injury if weighted vests are worn. 
 
RUN & MOVE HAPPY!
 
https://blog.myfitnesspal.com/read-this-before-you-walk-with-weights

https://www.livestrong.com/article/316367-is-a-weighted-vest-bad-for-your-back/

https://www.ncbi.nlm.nih.gov/pubmed/27638041

​https://www.ncbi.nlm.nih.gov/pubmed/10995045

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5788462/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414134/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4650105/#CR19