Aikido and Knee Injury Project
The Incidence of Acute Knee Injuries in
Aikido
Janet Rosen, R.N., B.S.N., P.H.N., ©
2002, 2011
While this article and the data in it
is copyrighted by the writer, it is my wish that the information be
spread, reported, and discussed freely ~ please let me know if you
are reprinting or excerpting it, and please DO always give me credit
and note the copyright. Thank you, and safe and joyous training!
In early 2000, I partly tore my right
ACL and damaged the medial meniscus while messing up an attempt to do
aikiotoshi. I trained carefully in a custom brace for nearly a year.
In January 2001, at a seminar, a
visitor used unneeded force on an opening, driving me to that knee
and leaving the joint so unstable that I would fall while walking. In
June 2001 I underwent surgery and then extensive rehab, returning to
training finally in the spring of 2002.
During the long hiatus, my "training"
was doing research (reviewing the field, interviewing athletic
trainers and doctors, and conducting a survey).
Aikido and Knee Injury Survey At A
Glance
Number of Dojo: 101 Members: 3250
Men: 75% Women: 25%
Men: 75% Women: 25%
Acute knee injuries in the past five
years: 99
No injuries: 50 dojo At least one injury: 51 dojo
No injuries: 50 dojo At least one injury: 51 dojo
Acute knee injuries, per dojo basis
Total: 4.45%
Men: 4.52% Women: 4.44%
Men: 4.52% Women: 4.44%
Acute knee injuries, per total
respondents Total: 3%
Men: 3% Women: 3%
Men: 3% Women: 3%
Sections:
Introduction
Survey
Warm-Ups
Dojo Size/Age
Mat Surfaces
Jumping Highfalls
Conclusion
Introduction
There is concern voiced within the
aikido community regarding knee injuries, but to date it has been
largely anecdotal. The Aikido and Knee Injury Project will gather
data on the incidence, causes and effects of knee injuries in aikido.
Part One focussed on the incidence of knee injuries, specifically the
number of adult students within each responding dojo who had an acute
knee injury related to their training during the past five years.
While some factors about dojo practice were examined, the goal was
not to extrapolate a cause, but rather to begin quantifying the
problem of knee injuries and to "take a snapshot" of
current practice.
Movement from the center and the taking of balance in aikido is characterized by circular movements. Most commonly this involves lateral turning of the body; that is, pivots in combination with steps or slides. It is often accompanied with vertical and/or spiral turning, with bending of the knees or a complete drop to kneeling. The overall effect is repeating torquing of the knees. In the course of a typical one hour class. a student might perform technique 120-200 times and receive technique (be pinned or thrown) 120-200 times. For the knees, this represents many repeated incidents of torquing, bending, and impact with the mat.
Movement from the center and the taking of balance in aikido is characterized by circular movements. Most commonly this involves lateral turning of the body; that is, pivots in combination with steps or slides. It is often accompanied with vertical and/or spiral turning, with bending of the knees or a complete drop to kneeling. The overall effect is repeating torquing of the knees. In the course of a typical one hour class. a student might perform technique 120-200 times and receive technique (be pinned or thrown) 120-200 times. For the knees, this represents many repeated incidents of torquing, bending, and impact with the mat.
The Survey
The survey was placed on two separate
interactive web pages to ensure anonymity. The first page included
identifying information for the responding dojo. The second page was
the survey itself. Dojo e-mail addresses were obtained from the web
sites of the various styles and organizations within the aikido
community. Over 300 requests were sent to individual dojo. In
addition, notices with live links were posted on the aikido-L (an
internet aikido mailing list) and on two general information aikido
web sites (Aikiweb and the Aikido Journal).
From around the world, 101 dojo,
representing all styles and affiliations, sent in complete, usable
responses. They comprise 3253 individuals over 21 years old,
practicing aikido in 15 nations. Follow-up questionnaires gathered
additional information, and 78 of the 101 original participating dojo
provided responses to the follow-up.
It needs to be stressed that, while I
was delighted to have over 100 responding dojo, this is a relatively
small sample. There is no factor that can be pointed to and
identified as "a cause of knee injuries." There are some
factors that, for reasons that are unclear, do seem to correlate with
a higher incidence of acute knee injuries.
|
|
Dojo with no injuries n=50 |
Dojo with few injuries n=11 |
Dojo with some injuries n=29 |
Dojo with many injuries n=11 |
|
Average no. of adult members |
30 |
64 |
32 |
14 |
|
Dojo as percent of whole study |
50% |
11% |
29% |
11% |
|
Percent of individual students |
45% |
22% |
28% |
5% |
|
Percent of total reported injuries |
0% |
13% |
57% |
30% |
Half of the participating dojo reported
NO acute knee injuries in training during the past five years. Fifty
one dojo reported a total of 99 persons had experienced acute knee
injuries in training. This is 3% of the total respondents; computed
on a per-dojo basis the average acute knee injury rate is 4.45%. The
figures are virtually identical for men and women.
Those half of the dojo reporting acute knee injuries were divided into three sections for comparison: those with the highest incidence of injuries (determined as those in the 80th percentile, which amounted to 11 dojo), the corresponding number of dojo showing the lowest incidence of injuries, and the remaining number comprising "some injuries."
What is intriguing is that the eleven dojo in the "high incidence" group represent less than 5% of the total adult members being reported on yet account for over 30% of the acute knee injuries. This accounts for the comment by many participating dojo that they really do not perceive knee injuries as a common problem, and raises the question of what, if anything, this group of dojo has in common with each other but not with the rest of the study group.
Those half of the dojo reporting acute knee injuries were divided into three sections for comparison: those with the highest incidence of injuries (determined as those in the 80th percentile, which amounted to 11 dojo), the corresponding number of dojo showing the lowest incidence of injuries, and the remaining number comprising "some injuries."
What is intriguing is that the eleven dojo in the "high incidence" group represent less than 5% of the total adult members being reported on yet account for over 30% of the acute knee injuries. This accounts for the comment by many participating dojo that they really do not perceive knee injuries as a common problem, and raises the question of what, if anything, this group of dojo has in common with each other but not with the rest of the study group.
Warm-Ups
|
Warm-Ups |
All Dojo n=101 |
No Knee Injuries n=50 |
Few Knee Injuries n=11 |
Some Knee Injuries n=29 |
Many Knee Injuries n=11 |
|
Bunny Hops |
.07 |
.06 |
.09 |
.03 |
.18 |
|
Knees SidetoSide |
.38 |
.36 |
.36 |
.31 |
.64 |
|
Knees in Circle |
.68 |
.64 |
.73 |
.69 |
.73 |
|
Seiza/Lie Back |
.58 |
.54 |
.73 |
.55 |
.64 |
The most commonly practiced warm-ups are standing and moving the knees in a circle and sitting in seiza and lying back. What stands out is that a significantly larger proportion of "many knee injury" dojo perform two of the warm-ups:
Bunny hops are only done in 7% of all dojo, but are done in 18% of the "high injury rate" dojo, double any other category and an increase of 157% above the respondents as a whole.
Standing with bent knees and moving them side-to-side is done in 64% of the "high injury rate" dojo, representing a 78% increase over the whole survey population.
It is not clear what this correlation signifies. It seems unlikely that the warm-ups in themselves are a factor. Is it possible that they indicate a certain higher intensity of practice that makes injuries more likely?
|
Seated Technique |
All dojo
n=101 |
No Knee Injuries n=50 |
Few Knee Injuries n=11 |
Some Knee Injuries n=29 |
Many Knee Injuries n=11 |
|
Never |
.06 |
.06 |
.00 |
.07 |
.09 |
|
Kokyudosa only |
.06 |
.08 |
.09 |
.00 |
.09 |
|
Not often, 1 or 2 techniques |
.62 |
.66 |
.73 |
.62 |
.36 |
|
Most classes, 1 or 2 techniques |
.23 |
.18 |
.18 |
.28 |
.36 |
|
Often much of a class |
.03 |
.02 |
.00 |
.03 |
.09 |
|
High frequency (last two groups) |
.26 |
.20 |
.18 |
.31 |
.45 |
|
Proportion of women members |
23% |
24% |
31% |
23% |
25% |
|
All dojo (n=101) |
High frequency seated technique (n=26) |
|
per dojo knee injury rate: 4.45% |
per dojo knee injury rate: 6.9% |
|
for men: 4.52% |
for men: 6.4% |
|
for women: 4.44% |
for women: 9% |
Most dojo report that they sometimes do
seated technique (suwariwaza or hamni handachi), but only for one or
two techniques and not often. The only place that this drops to under
60% is for dojo in the "many injuries" category, a quite
significant drop to 36%. Forty-five percent of the "many
injuries" category of dojo report doing seated technique with
high frequency. This is considerably more than is reported by the
dojo with lower incidence rates of acute knee injuries.
I decided to look at those twenty-six dojo reporting higher frequency of seated practice (23 that in most classes do one or two techniques suwariwaza or hamni handachi, plus 3 that often do classes consisting mostly or entirely of suwariwaza or hamni handachi). Six of them are in the "highest injury" group of dojo. Their overall injury rate is considerably higher than for the survey as a whole. When it comes to male-versus-female injury rates, it is the only factor noted in the survey to reflect a major discrepancy. This is not explainable by disparity in relative numbers of female students, who comprise a similar proportion of total members for this group and other groups.
It is not clear whether this correlation has to do with injury related to seated practice or, as with certain warm-ups, if it is a reflection of an intensity of practice. Whether the jump for women knee injuries is an anomaly is likewise unclear. Hopefully, surveying individuals who have been injured will shed some light on these issues.
I decided to look at those twenty-six dojo reporting higher frequency of seated practice (23 that in most classes do one or two techniques suwariwaza or hamni handachi, plus 3 that often do classes consisting mostly or entirely of suwariwaza or hamni handachi). Six of them are in the "highest injury" group of dojo. Their overall injury rate is considerably higher than for the survey as a whole. When it comes to male-versus-female injury rates, it is the only factor noted in the survey to reflect a major discrepancy. This is not explainable by disparity in relative numbers of female students, who comprise a similar proportion of total members for this group and other groups.
It is not clear whether this correlation has to do with injury related to seated practice or, as with certain warm-ups, if it is a reflection of an intensity of practice. Whether the jump for women knee injuries is an anomaly is likewise unclear. Hopefully, surveying individuals who have been injured will shed some light on these issues.
|
Dojo Size |
All dojo
n=101 |
No Knee Injuries n=50 |
Few Knee Injuries n=11 |
Some Knee Injuries n=29 |
Many Knee Injuries n=11 |
|
total adult members |
32 |
30 |
64 |
32 |
14 |
|
Years in Operation |
All dojo
n=78 |
No Knee Injuries n=35 |
Few Knee Injuries n=8 |
Some Knee Injuries n=27 |
Many Knee Injuries n=8 |
|
One to five years |
.19 |
.31 |
.12 |
.07 |
.13 |
|
Six to ten years |
.18 |
.17 |
.00 |
.26 |
.13 |
|
Over 10 years |
.63 |
.51 |
.88 |
.67 |
.75 |
When I first looked at data in a table,
it seemed like the number of students per dojo was correlating
negatively with the incidence of acute knee injuries. I looked at
injury rates for the groups of smallest, the most average sized, and
the largest dojo in the survey. Those smallest dojo had up to 9 adult
members and a per-dojo injury rate over 5%. A cluster of dojo around
the median and mean, with between 30 and 36 adult members, had a
per-dojo injury rate of close to 2.5%. The eleven largest dojo had
over 55 members each, and per-dojo acute knee injury rate of under
2%. So there was a trend.
One thought that came to mind was that smaller dojo might represent newer dojo. A follow-up survey was done to ascertain how many years the participating dojo had been in operation, with 78 of the original participating dojo responding. In fact, there was a relationship: Of the ten smallest dojo, 40% had been in operation five years or less, while all of the ten largest dojo had been operating six years or more. Another 40% of the smallest dojo had been operating over ten years, as compared to 60% of the largest dojo.
Looking at how long dojo had been open, two things stuck out: Of the dojo in operation five years or less, 22% were also dojo with "no injuries," higher than predicted based on their proportion within the survey. This may be because they have a higher proportion of beginners, who are not training at the speed or intensity that is associated with torquing knee injuries.
Of the dojo in operation for six to ten years, none were in the "small number of injuries" category, but 24% were in the "moderate number of injuries category." I am speculating that this may represent the tendency some aikidoka have noticed for students approaching shodan to become somewhat reckless in their training. For the dojo in operation over ten years, the numbers tend to balance out again.
One thought that came to mind was that smaller dojo might represent newer dojo. A follow-up survey was done to ascertain how many years the participating dojo had been in operation, with 78 of the original participating dojo responding. In fact, there was a relationship: Of the ten smallest dojo, 40% had been in operation five years or less, while all of the ten largest dojo had been operating six years or more. Another 40% of the smallest dojo had been operating over ten years, as compared to 60% of the largest dojo.
Looking at how long dojo had been open, two things stuck out: Of the dojo in operation five years or less, 22% were also dojo with "no injuries," higher than predicted based on their proportion within the survey. This may be because they have a higher proportion of beginners, who are not training at the speed or intensity that is associated with torquing knee injuries.
Of the dojo in operation for six to ten years, none were in the "small number of injuries" category, but 24% were in the "moderate number of injuries category." I am speculating that this may represent the tendency some aikidoka have noticed for students approaching shodan to become somewhat reckless in their training. For the dojo in operation over ten years, the numbers tend to balance out again.
|
Training Surface |
All dojo
n=78 |
No Knee Injuries n=35 |
Few Knee Injuries n=8 |
Some Knee Injuries n=27 |
Many Knee Injuries n=8 |
|
Tatami |
.05 |
.06 |
.12 |
.04 |
.00 |
|
Fake tatami/foam |
.26 |
.23 |
.38 |
.18 |
.50 |
|
Canvas over foam |
.23 |
.14 |
.25 |
.41 |
.00 |
|
Other permanent surface |
.15 |
.16 |
.12 |
.22 |
.12 |
|
Wrestling mat |
.10 |
.23 |
.00 |
.00 |
.00 |
|
Gymnastic mat |
.14 |
.14 |
.12 |
.08 |
.38 |
|
Other temporary/rollout |
.06 |
.09 |
.00 |
.08 |
.00 |
|
ALL permanent mats |
.69 |
.54 |
.88 |
.84 |
.62 |
|
ALL temporary mats |
.31 |
.46 |
.12 |
.16 |
.38 |
Of the original responding dojo, 78
followed up with information on the type of mats used for training.
There was a decent balance in this group between dojo reporting no
knee injuries (35) and those reporting any acute knee injuries (43).
A couple of numbers jump out:
Wrestling mats seem to correlate with no knee injuries (despite anecdotal complaints that feet stick to them). On the other hand, canvas stretched over foam surfaces seem to correlate with moderate numbers of knee injuries.
Finally, of the 11 dojo with the highest knee injury rates, eight responded, and 50% of these train on mats of artificial tatami/foam; given that this represents merely 4 dojo out of a small subset of 8, it is unreasonable to draw any conclusions other than to suggest that mat surfaces seems to be an area worth more detailed research.
Wrestling mats seem to correlate with no knee injuries (despite anecdotal complaints that feet stick to them). On the other hand, canvas stretched over foam surfaces seem to correlate with moderate numbers of knee injuries.
Finally, of the 11 dojo with the highest knee injury rates, eight responded, and 50% of these train on mats of artificial tatami/foam; given that this represents merely 4 dojo out of a small subset of 8, it is unreasonable to draw any conclusions other than to suggest that mat surfaces seems to be an area worth more detailed research.
|
Jumping Breakfalls |
All dojo
n=78 |
No Knee Injuries n=35 |
Few Knee Injuries n=8 |
Some Knee Injuries n=27 |
Many Knee Injuries n=8 |
|
Never |
.09 |
.09 |
.25 |
.07 |
.00 |
|
Sometimes |
.56 |
.60 |
.25 |
.52 |
.88 |
|
Frequently |
.35 |
.31 |
.50 |
.41 |
.13 |
Several people suggested that, as long
as a follow-up survey was going out, I inquire about the frequency of
jumping highfalls. This was defined on the survey as falls involving
having the whole body off the mat in forward rotation and landing in
a fall rather than a roll.
There is a disparity noted in the "many injury" category, with the overwhelming majority sometimes doing jumping breakfalls, but with substantially fewer of these dojo reporting that they frequently do them.
There is a disparity noted in the "many injury" category, with the overwhelming majority sometimes doing jumping breakfalls, but with substantially fewer of these dojo reporting that they frequently do them.
It was most gratifying to have such a
positive response. I believe that those who participated were open
and honest in their reporting, because so many included comments or
questions that reflected a real concern about how the art is doing on
this issue. We owe all participants a huge thank you.
Thank you to Jun Akiyama at Aikiweb and
to David Cody for technical assistance that made this project
possible, and to Joel Posluns and the members of Aikido-L for their
support and assistance with this project.
