CHANGES IN RUNNING GAIT. PARAMETERS DURING A 161 KM. TRAIL RACE. Sarah Clarke (nee Breen). Mitchell L. Stephenson. Randall Jensen.
CHANGES IN RUNNING GAIT PARAMETERS DURING A 161 KM TRAIL RACE
Sarah Clarke (nee Breen) Mitchell L. Stephenson Randall Jensen Scott Drum
Ultra Running & Trail Running
>42.2 km
Increasingly popular
Anton Krupicka 10,000 active ultrarunners worldwide (IUA) Rocky Racoon 2011
Trail running is the most popular form of ultrarunning
Pacing strategy
Essential to manage the detrimental effects of fatigue
Measureable factors: Running Stride
Speed
Length Stride Rate
Our investigation
16 race participants
162 km footrace 5
identical 32 km laps Observation point 27 km point of each lap 0 km
S T A R T
162 km F I N I S H
Rocky Raccoon Route
5 laps
~1680 m elevation change
Equipment & Set Up
60 Hz
5 laps • Speed • Stride Length • Stride rate
• Finish Time • Lap Time • Average Speed
What was assessed? CHANGE ACROSS LAPS
Speed (m/s) Lap Time (min) Stride Length (m) Stride Rate (Hz)
Measured variables
RELATIONSHIP TO RACE TIME RACE VARIABLES: # laps ran STDEV Lap times (s) STDEV Stride Length (m) STDEV Stride Rate (Hz) LAP VARIABLES: Lap Speed (m/s) Stride Length (m) Stride Rate (Hz) Race records
STDEV = Standard Deviation
Results CHANGE ACROSS LAPS All measured variables changed significantly across the 5 laps Speed
(m/s) Lap Time (min) Stride Length (m) Stride Rate (stride/s)
LAP TIME (min)
1
2 1
3 2
4 3
5 4
etween laps ↑ = significant increase between laps
5
STRIDE RATE (s)
LAP
STRIDE RATE (s)
STRIDE RATE (s)
SPEED (m/s)
STRIDE LENGTH (m)
STRIDE RATE (s)
0.8
200
5
(s) RATE LENGTH STRIDE (m) STRIDE
STRIDE RATE (s)STRIDE LENGTH (m)
(s) RATELENGTH STRIDE (m) STRIDE
Changes across Laps
STRIDE L
STRIDE STRIDE LENG LAP TIM
STRIDE RATE (s STRIDE LE
LAP
LAP TIME (min) SPEED
STRIDE LENGT
LAP TIM SPE
1.3 1.1 300 ** * ↓ 1.0 300 ↓ 0.5 0.5 450 250 1.1 ↑ ↓ 250 ↑ 1.4 0.9300 *↓ * ↑ 1.0 * ↑ * 300 1.1 0.9 1.1 0.5 250 0.9 250 0.0* ↑200 0.0 400 * ↑ 200 0.7 1.2 0.9 0.5 250 0.753 0.9 250 1 2 3 4 1 51 ↑ 2 3 4 0.0 5 200 1 2 0.7 32 4 200 54 0.5 * 350 1.0 1.7 1 2 31.7 43 0.5 540.7 1 200 0.5 30.7 4 0.0 5 200 1 2 15 2 1.8 3 2 4 1.8 ↑* 1 2 3 1 21 * 32 43 54* 1 0.5 4 5 300 21.8 32 decrease 43 51 0.5 1.5 2.5 0.8 1.7 1.5 ↓= significant b 1.8 1.6 ↓ ↓ * 1.6 ↓=2 significant dec ↓ * 1 1.7 2 1.8* 3↑* 4 5 1=*↓= 21 3decrease 43 betwe 1.8 significant * significantly different from all o 1.3 1.5 2.0 1.3 250 * = significantly different fro ↓ 1.6significant * ↓ 1.6 ↓ between ↓ ↓= 1.4laps * decrease ↓ ↓=1.5 significant decrease laps ↑ = significant increase between * = significantly different from all other la 1.4 1.6 ↓ ↓ 1.1 1.3 ↓ 1.1 ↓ =1.5 1.6 from* all other laps * = significantly different from all * = significantly different other significant differences between lap ↓ 200 ↓ 1.4 1.4 1.2 ↓ 1.3 1.2 ↓ ↓ 0.9 5 1.1 1 2 ↓ 3 0.94 1.0 5 1.4 1.4 ↓ 1.2 1.1 ↓ 1.2 1.0 1.8 0.7 0.9 1.0 0.7 0.5 1.2 1.2 0.9 1.0 0.5 1.0 0.7 0.8 0.5 1.6 450 0.0 0.8 1 2 31 42 1.02 53 3 0.7 1.0 4 4 551 1 ↓ 2 400 3 4 0.5 5 1 2 3 4 5 0.8 0.8 1.4 ↓= significant decrease laps ↑ =between significant 1 ↑ = significant 43↓= 5between significant laps ↑ 1 2 incr ↓ 23 increase ignificant decrease between lapsdecrease 3 4 0.5 between 5 0.8 laps 12 4 0.8 5 350 = significantly different from all other lapsfrom = 2other significa 1 laps *2↓= 3 4 = significantly 5differences * different all other laps 1 3 be y different from all other = other significant between laps significant decrease between laps ↑ = significant increase 1.2 4 5 1 2 increase 3 between 4 laps 5 nt decrease between laps ↑ = significant 300 *↓= = significantly different from all other = other significant differ significant decrease between lapslaps ↑ = significant increase between la ent from all other = other significant differences ease between lapslaps ↑ = significant increase between laps between laps * =1.0 significantly different from all other laps = other significant differences b 250 m all other laps = other significant differences between laps 1.3
*
STRIDE RATE (s)
300
1.4 1.2
STRIDE RATE (s)
↓
STRIDE RAT
*
350
STRIDE RATE (s)
Changes across Laps 1.0
↓
LAP TIME (
STRID
STRIDE LENGTH
STRIDE LENGTH (m)
STRIDE LEN
↓ ** 0.9 1.3 1.1 1.5 1.3 ↓ ↓ 0.7 1.1 0.9 1.3 1.1
STRIDE LENGTH (
SPEED (m
1.5
1.6 ↑
1.1
STRIDE RATE (s)
STRIDE LENGTH (m)
STRIDE LENGTH (m)
1.4 ↑ * 1.0 1.2 0.9 0.7 1.1 0.9 0.5 2503 1 2 4 51.2 0.7 1.0 0.8 0.7 0.5 0.9 ↓= significant decrease between lap 0.0 1 2 3 4 200 5 0.5 * = significantly different from all other laps1.0 10.5 2 0.7 3 4 5 10.8 2 ↓= significant decrease between 1 2 3 4laps ↑ =5 significan 1.7 10.5 2 3 4 5 1.8 10.8 1.7 * = significantly different from all other laps = other sig ↓= significant decrease between laps ↑ = 1.5 * 1 2 3 4 ↓= significant decrease between laps ↑ =5 significant in 1.5 * = significantly different from1.6 all other laps = * =↓ significantly different from all other laps = other signific * ↓= significant decrease between laps ↑ = sig 1.3 ↓ 1.3 * =↓significantly different from all other laps = oth 1.4 0.5
1.1
0.9 0.9 0.7 0.7 0.5 0.5
1.2 1.0 0.8
1
1 2
23
34
54
5
1
2
↓= significant decrease between laps ↑ = significant increase be * = significantly different from all other laps = other significant differ
*
*
Changes across* Laps 0.5
300 250
1.1 0.9
0.0
4
5 1.7
↓
STRIDE RATE (s)
STRIDE LENGTH (m)
1.5
1.1
1.2
0.5
4
5
1.6 ↓
1.4
0.7
1.8
* 1.6
1.3
0.9
3
1.8
STRIDE RATE (s)
3
200 1
1.0 0.8
1.4 1.2
20.7 1 0.5
↑
1.3
↓ ↓
350
* ↓
1.1
250
0.9 32 0.7
200 43
1.6
300
54
*
1
5
0.5 1
↑
*
1.4 1.2 1.0 2 0.8
1.8
2 3 4 5 1 2 3 1.6 4 5 ↓= significant decrease between laps ↑ = sign * ↓= significant decrease between laps ↑ ↓ ↓ different * = significantly from all other laps = othe ↓ 1.4all other laps * = significantly different from ↓ 1.2
STRIDE RATE (s)
1.0
↑
STRIDE RATE (s)
STRIDE LENGTH (m)
1.3
↓ 1.5 ↑
**
LAP TIME (
* 1.7
1.5
STRIDE LENGTH (m)
350
LAP TIME (
SPEED (m
1.5
1.0 0.8 1 1 21
2
3 32
4 43
5 54
1.0 0.8
5
1
2
significant decrease between ant decrease between laps ↑ = ↓= significant increase between laps laps ↑ = significant increase b different from all other between laps rent from all other laps * = significantly = other significant differences laps= other significant diffe
Relationship to race performance The following race variables were significantly * Correlation is significant at the 0.05 level correlated with finish time (s): ** Correlation is significant at the 0.01 level
0 km
S T A R T
# laps ran (r=-0.716**) Standard deviation of lap times (r=0.722**) Standard deviation of stride rate (r=0.668**) Standard deviation of stride length (r=-0.506*) 162 km F I N I S H
Relationship to Lap Performance The following lap variables, were significantly correlated with finish time (s): * Correlation is significant at the 0.05 level ** Correlation is significant at the 0.01 level
Lap 1
Lap 2
Lap 3
Lap 4
Lap 5
Speed (m/s)
-0.507*
-0.671**
-0.562*
-0.734**
-0.413
Stride Length (m)
-0.582*
-0.655**
-0.345
-0.637**
-0.387
Stride Rate (stride/s)
0.259
-0.300
-0.345
-0.494
-0.280
0 km
S T A R T
162 km F I N I S H
Conclusion
Running speed and running gait parameters in the current study are reported to change significantly across a 162 km trail race.
Increased speed and stride length correlated significantly with decreased finish time,
Consistency in stride rate and time for each lap correlated significantly with decreased finish time,
TAKE HOME MESSAGE EXPERIENCED ULTRARUNNERS
Time-Goal Orientated Perform first half of the race (at least) slightly quicker than goal time pace Run in a controlled manner consistently faster than goal pace for this period*
NEW TO ULTRA-RUNNING
*per terrain and elevation difficulties
Just want to finish Tightly control pace
Avoid an overly fast start and or finish
Acknowledgements Joe Prusaitis & the race volunteers
Grounds staff at Huntsville State Park. College of Health Sciences and Professional Studies, Northern Michigan University Physical Education & Sport Sciences Department, University of Limerick
Thank you for listening
Scott Drum
Mitch Stephenson
Randy Jensen
References
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