Camjams for shoes

User Story

Andrea is a woman with congenital spastic diplegia cerebral palsy (CP) seeking shoe modifications that allow her to tie her shoes independently, tightly, and easily, as well as provide more proprioceptive input necessary for safe ambulation.  CP impacts Andrea’s donning of shoes and safe ambulation because she experiences deficits in foot proprioception and decreased hand dexterity and strength.  Currently, Andrea ties her shoelaces as tightly as she is able to because the sensation helps improve her awareness of where her feet are positioned in space as she walks; however, it takes Andrea roughly 1-hr to tie her shoes, and this strains her upper extremities, contributes to several calluses on her hands, and generally fatigues her body.  Over her lifetime she has tried many combinations of tying and materials, and has found the most success with zero-drop (flat), leather shoes, a separate lace for every 2 pairs of eyelets, leather shoelaces, and custom orthotics. Andrea’s identified primary concerns are:

  1. to maximize her independence tying her shoelaces;
  2. to improve proprioceptive input to her feet via tying her shoelaces tightly;
  3. to minimize fatiguing/straining her upper extremities and protect her hands from calluses while allowing for finger dexterity as she ties her shoelaces
  4. to tie her shoelaces in a reasonable amount of time.

Problem Statements

User Need Statement:

Andrea is a woman with CP who experiences proprioceptive deficits in her feet and limited hand strength and dexterity, making independent shoe-tying and safe ambulation difficult.  Andrea ties her shoelaces tightly to provide deep pressure input to the tops of her feet; however, her need for tight lacing bruises the tops of her feet, fatigues her upper extremities, and causes callus formation across the lateral distal aspects of digits 3-5 and medial distal aspect of digit 2.

POV Question: 

How can we help Andrea tie her shoes independently, tightly, and easily and improve the proprioceptive input necessary to ambulate safely?

Design Process

Brainstorming Jamboard:

Initial Design:

  • flexible plastic “plate” between tongue and laces
    • purpose:
      • evenly distribute pressure across the top of the foot
    • design:
      • cushioned by gel/foam
        • identified several suitable materials
      •  molded to shoe’s tongue from lighter plastic piece and a thicker thermoplastic/splinting piece

Instructor feedback:

  • be cautious of pinch points
  • mind foot’s bony landmarks
  • allow for foot to move naturally
  • splinting thermoplastic is probably too heavy
    • try a lighter plastic or laminating a few layers of cardstock
    • pick a flexible material

Client feedback

  • excited to try this idea
  • doesn’t want plate to be stiff or bulky
  • recommends a tongue-shaped and/or I-shaped plate
    • allows flexibility during ambulation

  • camjam: alternative method for holding tension in shoelaces without straining body 
    • purpose:
        • minimize strain on Andrea’s upper extremities and shoulders, reduce hand calluses
    •  went to Bass Pro Shop, Dick’s Sporting Goods, Home Depot

  • HOW to anchor camjams  
    • design:
      • wrap webbing around shoe (run under shoe via gap between tread in sole/toe area of shoe) and attach via eyelets
      • anchor camjams to webbing via cloth loops sewn into webbing


Client’s feedback

  • concerned that the webbing under the shoe will be a tripping hazard
    • likes webbing under the shoe as a temporary mock-up, willing to try it
    • if idea is pursued, she would hire a professional shoe repairperson to sew webbing directly into the shoe vs running under it

  • WHERE to anchor camjams
    • design:
      • anchor 1st camjam on proximal, lateral side of shoe
        • via cloth loop and webbing
      • anchor 2nd camjam on distal, medial top side of shoe
        • via cloth loop and webbing
      • possibly place a buckle across the center top of shoe
        • via cloth loop and webbing

Client feedback:

  • preference for 1st shoelace and camjam on eyelet pairs 1 + 2 (distal), buckle over eyelet pairs 3 + 4 (middle), 2nd shoelace and camjam on eyelet pairs 5 + 6 (proximal)
  • willing to try other other placement of camjams

Revisions and Design Updates:

Client provided feedback on

  • camjam placement, lacing order, how to secure camjam on shoe, lacing materials
  • the flexible plastic tongue plate was fine when she was stationary, but when she started walking, it was too inflexible and hard for walking, and it shifted in place.

Updated designs including:

  • webbing anchor
  • flexible plastic tongue plate

Other considerations:

  • gloves
  • hiking boot hooks
  • Andrea needs ankle support
  • avoid any overlapping of materials
  • Andrea reports a lot of pronation and lateral motion when she ambulates

Andrea, her mother, and the group discussed that while one of the final two prototypes she will be presented will address most of her concerns, it would be beneficial to use the prototypes with a professional who can use them as a guide to make permanent modifications to the shoe.

Andrea decided that for maximal pressure the CamJams were the better option. The final design will incorporate more CamJams to provide even further pressure and adjustability. The shoe will have 3 sets of CamJams on either side with laces running through them and webbing across the bottom, with both the top and bottom webbing running under the tread. Andrea’s plan is to try walking on these shoes with her walker when she has them for a longer period of time following completion. Her intent is to use this as a guide to take to a professional who has the equipment and training necessary to modify the shoes themselves so that the webbing won’t run under the tread and the design will be incorporated fully into the shoe.

Initial lacing pattern:

  • really tight, easy and fast to pull taut, easy and fast to release
  • proprioceptive holes on sides without camjams
    • unclear if this was due to lacing pattern or just single sided anchoring

Other Lacing Patterns:

  1. Was inspired by a common one handed lacing technique, however it proved to have proprioceptive gaps because of unevenness of tension on both sides at different points.
  2. Was inspired by corset lacing, which allows for very tight lacing with good hold, however it was too difficult to tighten, especially in the middle of the shoe, and could not just be pulled 1 handed.
  3. Used a trucker’s hitch to pull tension on opposite side of CamJam, similar to how a boot lace hook would, but ultimately with the shoe laces we had it didn’t glide well enough to make it good economy of energy – requiring pulling fairly hard medially then laterally, which put strain on her elbow as the direction switched.

Ideas given for who to approach to make alterations to her gloves to reinforce key pressure areas with leather (several good leather craftsmen in area as well as several traveling vendors that specialize in custom leather gloves for celtic/ren faire type affairs). Note: During the design process, several attempts were made to virtually “fit” finger protectors or patches without having her hands, but because precision is so key (even a millimeter of extra wiggle room/ill fit can cause more blisters vs prevent them), without having her hands physically present and the current skill of the group members in glove crafting, it was determined by Andrea and the team to not pursue this avenue.

We did not have time to lace in boot hooks in an operational way for her to try and she wanted us to focus on the CamJams. Post-design challenge we agreed to continue to work with her on our own to get those operational on the webbing system so she can feel what boot hooks would be like to pull on vs eyelets, because she has been wanting to experiment with them but couldn’t figure out how.

Final Design

Andrea decided on a final design of 6 camjams per shoe (3 medially and 3 laterally) placed on top of the shoe with 1 camjam per pair or eyelets.  Andrea noted that this lacing system:

  • allows her to individually adjust each camjam
  • allows her to adjust specific areas of the shoe
  • provides even pressure across the top of the foot
  • provides even pressure on both sides of the foot
  • has easy-to-use fast locking and release mechanisms


Our final design consists of two parts: 1) A webbing attachment system which can be used to anchor, and therefore simulate, components which usually require permanent modification to the shoe, and 2) a lace locking system that potentially allows the tightening of our client’s shoes with decreased time and strain while still providing sufficient pressure for proprioceptive input.

The webbing attachment system uses industrial polypropylene webbing with inserted metal grommets to anchor at the eyelets while still allowing the passage of laces, and wraps under the shoe from one side to the other. Things like loops, buckles, or hooks can then be sewn into the webbing instead of the shoe itself, simulating their effect. The ability to accurately simulate the effect is important because Andrea’s needs over time are dynamic. However, her specific shoe requirements mean she has purchased a stock of the same model of shoe, which is no longer made, and therefore the supply is limited. She has wanted to be able to try different shoe mechanisms on her own shoe, but was afraid of damaging her dwindling supply.

The lacing system utilizes 6 short individual laces and 6 CamJams, a cord tightening mechanism used in boating and camping anchored to the side of the shoe or webbing system, to shorten the time and strain necessary to “tie” her shoes with sufficient tension to provide the required proprioceptive input for her to walk independently. The laces are knotted on one end and fed from the top through the eyelet on the same side as the CamJam it will feed into. They then pass through the eyelet directly across before passing over the top of the shoe and feeding into the CamJam, anchored to the side of the shoe or webbing. To tighten the shoe, one pulls the end fed through the CamJam up and away from the anchor point of the device, sliding the lace into a channel on the device to secure it, repeating for all 6 devices. To release the mechanism, you pull the lace up and toward the mechanism once more.

Alternatives considered/attempted Reason discarded
Leather or cloth for strapping system Too stretchy and not as durable
Chicago screws or screws with washers through eyelets to anchor webbing Cannot use the eyelets for lacing
Buckles, ratchet straps, V-Jam cleats, and cam cleats Too large for shoe, did not provide enough tension, too difficult to operate, or could not procure in time
Alternative lacing methods (inspired by corset lacing, zipper lacing, and one handed lacing)
Too difficult to pull or not tight enough



Materials and Budget (per shoe):

  • Tools
    • lighter
    • grommet clamp
    • small sewing scissors
    • leather punch (optional, can use scissors)
    • needle
    • sewing machine (optional)
  • Materials
    • 40 inches of 1 in. width webbing (depending on shoe) $9.14 for 10 yards

      = $1.02 for project

      12 inches of length of 1/2 in. width webbing $8.95 for 10 yards

      = $0.30 for project

      12 grommets $3.98 for pack of 12
      thread $1.98 for 400 yds
      6 Nite Ize CamJams (1 3/4 in. size) $6.49 for pack of 2 x 3 packs

      = $19.47

      3 pairs of 36 in. – 45 in. shoelaces (1.8 mm – 3 mm width) $3.50 per pair x 3 pairs

      = $10.50

      Total cost for 1 modified shoe:   $37.25

Product critique


  • One of the strengths of this design was the use of webbing material to create a system that different mediums could be switched in and out of for Andrea to try without any permanent modification to the shoe itself.
  • Webbing system is able to simulate permanent modifications without any damage to the shoe
  • The webbing is very durable and easy to modify, and therefore highly versatile.
  • CamJams hold sufficient tension for proprioceptive needs
  • CamJams are easy and fast to lock/unlock
  • CamJams are easy to replace when they wear out and simple to commercially purchase
  • 3 CamJams per side allow for even tension on both sides without proprioceptive holes and refined customization


  • Durability and long term viability of the CamJams is unknown
  • Requires permanent modification to the shoe (preferably by a professional) to be functional long term
  • The number of laces can be confusing to initially navigate
  • Smaller width laces (1.8mm-3mm) are required to use the CamJams, which are still rough on the hands in the absence of a tool
  • If the loose ends of the laces are not secured properly they could be a safety hazard for tripping or for the shoe coming untied unintentionally
  • The portions of the webbing system that are under the tread are slick, making it difficult to walk during testing without a balance aid
  • The double sets of eyelets may create increased friction on the laces (good or bad) during testing
  • This design prioritizes function over fashion
  • Cost

Suggestions on how to improve the design/construction: 

  • Use thinner weight webbing so it is less bulky
  • Use something on bottom of webbing to increase friction with ground for testing
  • See if a cam system that is sufficiently small can be made in metal instead of plastic to increase durability
  • Experiment with lace types that are small enough to fit in mechanism to see which are the easiest on the hands
  • Consult with costuming leatherworkers for professional modifications to reinforce gloves


Manufacturing instructions: Andrea’s Manufacturer’s Instructions

User instructions: User Instructions (1)

Written instructions: Written User Instructions

Student designers: Victoria Britt, Kerry Flanagan, Katherine Goracke, Nancy Milroy

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