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April 22nd, 2019 Copyright Motus Global Inc.
Page 1 of 6
Modeling Elbow Valgus Torque From Throwing Distance With 627,925 Baseball Throws By
Competition Level
Ben Hansen, Brittany Dowling, Will Carroll
Motus Global, Rockville Centre, NY, USA
INTRODUCTION: The scalability and usability of inertial measurement units (IMU’s) allows
for biomechanical research to be conducted on datasets that are orders of magnitude larger than
traditional motion-capture equipment allows for. IMU’s also allow for capture of data in real-
world settings rather than in a laboratory. Elbow injuries and revisions in pitchers have been on
the rise for the last 30 years; however, there lacks evidence-based criteria for rehabilitation of the
throwing arm. From both a clinical rehabilitation and return-to-throwing perspective, there is a
large need to better understand the effects of throwing distance on elbow valgus torque by
competition level.
PURPOSE: To develop a data-driven framework for the prediction of elbow valgus torque at
specific long-toss distances during baseball throwing at various competition levels.
METHODS: Data were mined from 20,000 motusTHROW users who wore a Motus IMU and
sleeve (Rockville Centre, NY, USA) that measures peak elbow valgus torque during throwing. A
total of 627,925 anonymized throws were mined with the primary tag of “Longtoss” which can
be set in the motusTHROW mobile application. Secondary tag (distance) of each longtoss throw
was also extracted. Peak torque was normalized by player height and weight, and were sub-
divided by competition level (Little League, High School, College, Professional, and All)
The 627,925 throws resulted in 25 different distance categories and 4 competition levels. The
inclusion criteria of a distance category was to require 1000 or more throws tagged with the
specified distance. A one-way ANOVA was performed to test for differences in elbow torque
between throwing distance with Tukey post-hoc tests used to for p-value calculation. The
significance level was set at p< 0.01.
RESULTS: Of the total 300 distance relationships in all combined levels, only 10 combinations
did not have statistically significant differences: A) 140-300’, B) 130-170’, C) 170-250’, D) 110-
160-210’, E) 180’-230’, F) 150-190-230’, G) 150-190-220’, H) 120-220’, I) 90-100’, and J) 30-
70’ oz (p < 0.01). The three highest elbow torques were associated with 270’ (2.84), 240’ (2.74),
and 140’ (2.60). Results for all distances can be seen in Table 1 and Figure 1 below.
DISCUSSION: In the aggregate dataset, elbow valgus torque was lowest at the shortest
distances of throwing. Starting at 30’, elbow torque increased with distance up to 140’. Between
distances of 150’-230’, elbow torque actually decreased by 16%, suggesting that throws made at
these distances are naturally done at lower accelerations with more loft and a higher ball release
angle.
In the aggregate dataset, starting at 240’, valgus torque starts to rapidly increase, with throws at
270’ being the most stressful of all throwing types. The reason for this may be that after 240’,
throwers must alter mechanics to increase release angle, resulting in large arm accelerations.
Additionally, throwers capable of throwing this far require ample velocity. Knowing that the
relationship between velocity and torque is extremely linear, this gives credence to this cause.
April 22nd, 2019 Copyright Motus Global Inc.
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In the subset of professional pitchers (n = 47,557), elbow torque was highest at 200 and 300 feet,
with torque generally progressing as distance increased. In the subset of collegiate pitchers, (n =
237,695), torque was highest at 240 and 270 feet, with a spike in torque at 140 feet. At throwing
distances of 140-210 feet, torque was only moderately elevated, suggesting that collegiate
pitchers may use moderate distances of longtoss for more therapeutic throwing than
professionals.
The subset of high school throws (n = 220,849), shows a similar trend to the collegiate
population. In this group, torque were highest at 150 and 180 feet, with reduced torque levels at
190+ feet. This may suggest that longtoss in this population is generally done with less effort, or
only tolerated by players who generate lower elbow torque. Further investigation is required.
In the subset of little league throws (n = 1,745), a more traditional relationship between distance
and torque were observed. While the volume of throws in this subset is extremely limited, the
highest torques were observed at the largest throwing distance of 150 feet.
CONCLUSION: The original purpose of this investigation was to model elbow torque with
throwing distance, to better help practitioners and coaches set safer limits in pitchers. While the
results show inflection points around 140 feet and 230 feet of throwing distances for increased
and decreased elbow torques, the subset of data show varying results.
As such, the findings suggest that longtoss at moderately long distances can be both therapeutic
by producing lower elbow torques, or can increase injury risk by producing higher elbow
torques. The data does not allow for a blanketed recommendation to be applied either as an
aggregate or by competition level. Rather- the data suggests that individuals who partake in
longtoss should undergo biomechanical analysis to individualize the limit of longtoss distance.
Players should continue to use longtoss to build arm strength and improve arm health, but only to
the degree that throwing at increased distances does not result in a) elevated elbow torques, b)
abnormal mechanics in planes of motion that are un-trained, c) when chronic workloads are low,
and d) when acute:chronic ratios become elevated. As always, athletes should perform throwing
programs while undergoing a strict workload-monitoring program and under the supervision of
their coach, performance staff, and (when applicable) their medical staff.
April 22nd, 2019 Copyright Motus Global Inc.
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Table 1. Mean (+/- Standard Deviation) of Elbow Valgus Torque with various weighted balls
Distance
Normalized Valgus Torque (%BW*HT)
N
Significance
30
0.0164+/- (0.0091)
22390
j
40
0.0146+/- (0.0104)
2357
*
50
0.0187+/- (0.0085)
8713
*
60
0.0201+/- (0.0086)
22162
*
70
0.0162+/- (0.0095)
2313
j
80
0.0233+/- (0.0086)
7643
*
90
0.0198+/- (0.0091)
64637
i
100
0.0197+/- (0.0094)
12011
i
110
0.0225+/- (0.0087)
5267
d
120
0.0209+/- (0.0089)
129263
h
130
0.0249+/- (0.0069)
4138
b
140
0.026+/- (0.0076)
2937
a
150
0.0217+/- (0.0086)
94355
f,g
160
0.0226+/- (0.0076)
2701
d
170
0.0248+/- (0.0076)
1447
b,c
180
0.022+/- (0.009)
142143
e
190
0.0215+/- (0.0082)
8318
f,g
200
0.0206+/- (0.0096)
10976
*
210
0.0224+/- (0.0096)
56851
d
220
0.0213+/- (0.0088)
2307
g,h
230
0.0222+/- (0.0098)
1186
d,e,f
240
0.0274+/- (0.0077)
7035
*
250
0.0243+/- (0.0085)
2976
c
270
0.0284+/- (0.0076)
4152
*
300
0.0256+/- (0.0099)
9647
a
Note: *significantly different from all distances. (a-j) are significantly different from all
distances except between a) 140-300’, b) 130-170’, c) 170-250’, d) 110-160-210’, e) 180’-230’,
f) 150-190-230’, g) 150-190-220’, h)120-220’, i) 90-100’, and j)30-70’
April 22nd, 2019 Copyright Motus Global Inc.
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Figure 1 – Bar chart of competition level by throwing distance, with gradient color coding of
peak elbow valgus torque.
April 22nd, 2019 Copyright Motus Global Inc.
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Figure 2 – Scatter plot (with standard deviation error bars) of distance versus peak elbow valgus
torque in the aggregate dataset of throws (n = 627,925).
April 22nd, 2019 Copyright Motus Global Inc.
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(a) (b)
(c) (d)
Figure 3- Scatter plot (with standard deviation error bars) of distance versus peak elbow valgus
torque in (a) professional throwers, (b) collegiate throwers, (c) high school throwers, and (d)
little league throwers.