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Running Technique – Dr Neil Miller 15/04/2015
1
Gait Analysis and the
Mechanics of Running and Injuries
Dr Neil Miller Director, Core Analyst Ltd.
Westbury Harriers, 13th April 2015
‘Survey’
• Are you interesteda) As a coach (including sports teacher and PTI)b) As a physio (or other therapist)c) As an athlete?
• Do you (or your client base) covera) Sprints (and jumps)b) Middle distance and club road and cross-countryc) Fitness and recreational running?d) Young athletese) Triathlon
© 2015
Handouts
Slides available as pdf
• Westbury Harriers site ‘members only’ area
• Others please sign up
• Also sign up for ‘Core Analyst’ newsletter
© 2015
Between 1992 and 2003, Paula Radcliffe’s maximum oxygen uptake stayed roughly the same, but her running economy improved by 15%
� 2:15:25 world record
Overview
© 2015
Max. O2 Uptake Running Economy
Running Technique – Dr Neil Miller 15/04/2015
2
Overview
• What do we ‘need’ to do to run? (Physicist)
+ How can your body perform this (Anatomy)
� Train for more efficient running,
with fewer injuries (Coach)
© 2015
Overview
• The Running Cycle (Outline)
• The same physics for runners of all types
• The big forces: gravity and momentum (inertia)
• If only we had wheels instead of legs!
• Wind resistance is actually quite small
• Rocking and twisting(the penalty of having two arms and two legs)
© 2015
Overview
• Slow Motion Video
• 240 fps = 1/8th speed
• Two cameras - side and end cameras (different runs stitched together with software)
• Comparative studies may be clocked at different rates
© 2015
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Running Technique – Dr Neil Miller 15/04/2015
3
Follow-On
• Practical drills and exercises• 7pm Thursday 14th May, Coombe Dingle
• Structured as per this talk (slight re-ordering)
© 2015
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Forces and Phases
• The big forces: Gravity and ‘momentum’ (overcoming inertia)
• Leg movement – the phases
• Stance (or Contact)
• Flight (or Aerial)• Recovery (or Swing) = Flight + Stance + Flight
• Stance:First Contact � Braking (or Cushion) � Mid Stance
� Drive (or Propulsion) � Toe Off
Gravity and Momentum © 2015
Minutes/Mile Relative Speed Energy ↑(Pugh, 1971)
2:40 min 22.5 mph 13%
4:00 min 15 mph 6%
5:20 min 11.25 mph 3.3%
6:40 min 9 mph 2.1%
8:00 min 7.5 mph 1.5%
(Air Resistance)
How much energy used in overcoming wind resistance (relative speed)?
Gravity and Momentum © 2015
Running Technique – Dr Neil Miller 15/04/2015
4
(Air Resistance)
Gravity and Momentum © 2015
� Ignore air resistance in basic model, (treat it as an
adjustment, later)
+ Newton’s First Law
� Drive is mainly needed to compensate
for braking
(waste of energy)
Weights and Measures
Typical rates and
timesSprints
Club
1500mFitness
RR *
LeaderRR Tail
Steps / minute 270 200 170 195 160
Contact time 0.10 s 0.15 s 0.23 s 0.20 s 0.31 s
Flight time 0.12 s 0.14 s 0.12 s 0.10 s 0.06 s
Recovery time 0.34 s 0.44 s 0.47 s 0.41 0.43 s
Average force 2.2 bw 1.9 bw 1.5 bw 1.5 bw 1.2 bw
Peak force (est.) 3.5 bw 2.9 bw 2.1 bw 2.1 bw 1.6 bw
Gravity and Momentum © 2015
* RR = Riverbank Rollick (muddy 10 miles), filmed 4 miles in.
Weights and Measures
% of
Total
55 kg Youth
or Woman72 kg Man
Leg (each) 10% 5.5 kg 7.2 kg
Arm (each) 6% 3.3 kg 4.3 kg
Head 8-9% 4.7 kg 6.1 kg
Torso 60% 33 kg 43 kg
Gravity and Momentum © 2015
Gravity
• Peak force on the ground
• 2 to 3½ x bodyweight (peak) off one leg
• The lifting muscles
• Gluteus maximus and quadriceps
(also hamstrings and adductors)
• Running (stance phase) = rapid lifting
• Peak force ~0.05 – 0.12s after landing
���� Need Pre-engagement of muscles ≡ correct landing
Gravity and Momentum © 2015
Running Technique – Dr Neil Miller 15/04/2015
5
Momentum
• Halt backwards rotation, move the leg forwards, and halt again, ready for landing
• ~5.5 – 7.2kg leg recovers in ~ ⅓ – ½ sec• Hip and knee flexors: Rectus Femoris & Iliopsoas
• Halting the leg: The hamstrings
• Overcoming Gravity v Overcoming Momentum• Handling one well ↔ handling the other well
Gravity and Momentum © 2015
The Big Force Breakdown
Importance seen when things go wrong!(Ignore hips for now)
• The “Big Force Breakdown”
• Chicken and Egg:Braking heel-strike � Long push �
Leg left behind �Foot arrives late, hamstring braking �
Braking heel-strike…
• Also no pre-engagement � running low
• Hallmarks: Leg left behind; shin swings through late
Gravity and Momentum © 2015
(The Big Force Breakdown)
Sprinters particularly affected
• Historically, plagued by hamstring problems
• Understanding gait leading to big improvements
• Trickle-down to endurance running
• (Tony Hadley national sprints coach mentor)
Unfortunate Consequence of Pre-Engagement:• Outwards rotation just before landing
(Common amongst sprinters)
Gravity and Momentum © 2015
What to Watch For
What to look for in real life (BFB):• Impression of the legs
Gravity and Momentum © 2015
Good Bad
Foot flat, shin vertical Breaking heel-strike
Short sharp drive Long drive
Foot tucked under ‘Leaving the leg behind’
Good knee drive Lack of knee drive
Tall, urgent action Sinking, long loping stride
Running Technique – Dr Neil Miller 15/04/2015
6
Motion of the Foot
Even foot flight Leaving the foot behind
© 2015Gravity and Momentum
Watch the flight of the foot• Foot ‘left behind’, tucked behind, falls steeply, jerks back on landing
Potential Consequences
• Waste of Energy• Heel-strike:
• Front shin pain, stress fractures �
• Aggravate any pronation problems (q.v.)
• Running low, over-striding:• Patella tendon strains, Osgood Schlatters,
patellofemoral pain
• Reach and breaking • Hamstring overuse
Gravity and Momentum © 2015
Causes
What causes this?
• Unbalanced training (too much distance, running tired)
• Other sports (football, rugby, triathlon)
• ‘Style switch’
• Benefits as well as problems
• Growing (bone length before muscle mass)
• Sitting down (underactive gluteus maximus, tight iliopsoas)
• Poor control of the pelvis (more later…)
Gravity and Momentum © 2015
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Running Technique – Dr Neil Miller 15/04/2015
7
Tendons and Fascia
The ‘Stringy Bits’• Tendons (e.g. Achilles tendon)
connecting muscle to bone
• Not always given separate name (‘hamstrings’ = muscle + long tendons)
• Fascia (e.g. Plantar Fascia) covering and connecting
• ‘Aponeuroses’ (≡ Fascia)
All have similar composition & properties
Elastic Bands and Energy Return © 2015
Muscle v Tendons
Muscle Tendon, Fascia
(Inelastic) Elastic (80% - 93% energy return)
Eats up energy when engaged No energy required
Adapt in weeks (or days) Adapt in months
Loved by coaches, PTIs, sports scientists
Loathed by surgeons
Relatively weak Strong (by cross-section)
Variable force / Variable length (Hooke’s law: δ. length ∝ force)
Elastic Bands and Energy Return © 2015
Running Economy
• Muscle and tendon often paired in a chain
• Muscles used as ‘adjustable spanners’; Tendons used as elastic bands
• Achilles tendon and calf muscles (+ Plantar fascia)
• ‘Hamstrings’ (both stopping the swing and tucking the foot)
• Patellar tendon and quadriceps
• Up to 50% energy can be recycled
Elastic Bands and Energy Return © 2015
Potential Injuries
• Muscle adapts faster than fascia/tendon� Fascia/Tendon strains when building up
(e.g. Plantar fasciaν, Achilles tendon)
• Muscle atrophies faster than tendon� Muscle strains when coming back
(e.g. calf muscle)
� Introduce speed work progressively but consistently+ Come back from injuries slowly
Elastic Bands and Energy Return © 2015
Running Technique – Dr Neil Miller 15/04/2015
8
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
• Weight pushed down in front
• Spine (only) pushes up
• 24 joints �Mechanically Unstable
Instability of the Back
© 2015Posture and Core Control
Thoracolumbar Fascia (TLF)
© 2015Posture and Core Control
• Key central structure• Fascia, connects to spinous
process
• Thick, strong, deep
• Mechanically important
• Multiple muscular attachments• At edges, top and bottom
• Multi-layer, encloses muscles
Simplistic Analogy
• Smooth fly-sheet on a tent• Muscles are ‘guy ropes’; correct length / gentle tension
• Backbone (spinous process) defines the shape
© 2015Posture and Core Control
Running Technique – Dr Neil Miller 15/04/2015
9
Posture
• Long (straight) back≡ Smooth even TLF
• Muscles as guy ropes• Adjustable length
• Any over-tight or slack muscle affects the whole
• Slight (natural) lean• Average drive up spine
• Stability mechanics
• Wind resistance
© 2015Posture and Core Control
Rectus Abdominis
(RA)
↕(6 or 8 Pack)
(Little Fascia)
Abdominals and Fascia
© 2015Posture and Core Control
TransverseAbdominals
(TA)
↔
Note the fascia (in white)
Note attachments:TLF; Pelvis
‘Core’ Connections
© 2015Posture and Core Control
Transverse Abs form a continuous girdle with the TLF ″ Internal Obliques
Core Control ↔ Posture
All abdominals have connections
to the pelvis
Controlling the Pelvis
© 2015Posture and Core Control
Pelvis: ‘Chassis’ of the body
Control of abdominals ↔
Control of the legs
Poor control of pelvis �big force breakdown
• (more later …)
� Need good use of core abs to run properly
Running Technique – Dr Neil Miller 15/04/2015
10
What to Watch For
Watch for:• Shape of the back (‘posture’)
• Forwards lean• = Hips Behindc
• Core• Tilt of pelvis (tuck T-shirt in)• Hinge at lower back
• Foot left behind mechanics, BFB
In real life
© 2015Posture and Core Control
Causes
© 2015Posture and Core Control
What causes this?• Posture
• Study; Nintendo
• Attitude (feeling down v sparky)
• Other sports (football, cycling, orienteering)
• Core / Control of Pelvis• Tight hip flexors (sitting down)
• Lack of lifting (homeowner lifestyle), asymmetry ~
• Underweight (growing etc.)More later …
M
Potential Consequences
© 2015Posture and Core Control
What consequences and injuries might result?
• ‘Foot left behind’ gait and associated injuries
• Lower back pain, stress fractures
• Loss of control of pelvis �
• Hip drop, crossing over … (more later)
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Running Technique – Dr Neil Miller 15/04/2015
11
Doing the Twist
• Push/pull legs forwards/backwards
• 2 x 7kg, offset from centre
≡ Twisting about vertical axis
• Arms counter-swing• Lighter but wider offset
� Need to ‘couple’ shoulders + pelvis
� Use of oblique muscles
Twist board demonstration
© 2015Doing the Twist
Diagonally Linked
ObliquesExternal
⁄Internal
Abdominals and Fascia
© 2015Doing the Twist
Internal Oblique
^
Abdominal Coupling
© 2015Posture and Core Control
Coupling
Coupling
• Connection between upper trunk (shoulders) and pelvis to control hip rotation
• Coupling via (abdominal) obliques
• Used with forwards swing ����
• Coupling via back (Lats, TLF)
• Used with backwards swing (�)
© 2015Doing the Twist
Running Technique – Dr Neil Miller 15/04/2015
12
What to Watch For (Arms)
• Drive through back
• Over-use of back instead of abdominals
• Hips rotate, leg corkscrews after drive
• Poor coupling between shoulders and pelvis
• Helicopter arms
• Underweight athletes
• Tight shoulders
• Quiet arms, high hands, wide arms, etc.
© 2015Doing the Twist
What to Watch For (Legs)
Uncontrolled torsion in hips (one leg driving forwards vs other leg driving back �
• Difficulty Controlling Knees
• Lack of coupling between shoulders and pelvis
• Aggravated by tight hip flexors
• Other examples (including asymmetric arm and knee action)
• (more with next section)
© 2015Doing the Twist
Causes
What causes this?
• Upper body problems (arms and obliques):
• Weak abdominals, especially obliques, also pectorals etc.
• Over-use of the back (lats, etc.)
• Habitually poor technique
• Tight shoulders (stress, backpacks, lack of stretching)
• Big force breakdown (see Gravity & Momentum)
(Consequences – with Rock and Roll below)
© 2015Doing the Twist
Overview
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Running Technique – Dr Neil Miller 15/04/2015
13
Hip Drop
Offset between leg joint and body centre � hip drop
© 2015Rocking and Rolling
Side Lean
Side lean is a ‘cheat’, with a similar cause
© 2015Rocking and Rolling
What to Watch For
Examples• Hip drop
• Line of shorts
• Tuck T-shirt in! Different coloured shirt + shorts
• Wide arm (‘right hook’); Rise of shoulder
• Side lean• Sway of body
• Focus on distant tree
Hard to Spot
© 2015Rocking and Rolling
Causes
What causes this?
• Weak (or inhibited) ‘hip abductors’
• Weak or unused (abdominal) obliques
• Women usually have broader hips
• Other sports, unequal use of each side
• Footballer’s syndrome
© 2015Rocking and Rolling
Running Technique – Dr Neil Miller 15/04/2015
14
Potential Consequences
What consequences and injuries might result?• Lower back problems (scholiosis)• Internal hip problems• Knee problems from Knee rotated or collapsing in
• Rotates in (hip drop or pronation, see below); or
• Planted in (swings with foot out)• Torsion of femur v tibia
• ITB (TFL) overuse – see below
© 2015Rocking and Rolling
Overview
© 2015
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
Line of Feet Cross-Over
Line of feet ‘cross-over’
• Knee swings across / hip drop / side lean / outwards drive
Effects:
• Tight ITB (why?)
• Tensor fascia latae over-use
• Pain at outside of knee
• Foot lands on outside and rolls sharply inwards �Over-Pronation…
© 2015Hitting the Ground
Pronation - Causes
(Over-)Pronation
• Causes:• Lack of support in shoe (worn or inappropriate)
• Poor lacing (loose – young athletes; use of power lacing…)
• Line of feet cross-over +Foot planted outwards, also supinated foot plant
• Tight hamstrings, et al
• (Outwards rotation just before landing)(already covered; pre-engagement)
• Aggravated by heel-strike
© 2015Hitting the Ground
Running Technique – Dr Neil Miller 15/04/2015
15
Pronation - Effects
Effects:• Medial (inside edge) shin pain
• Plantar fasciitisAlso caused by ↑ mileage (see slides on fascia)Also flat foot, high arch, tight Achilles
• Knee problems ( rotation of the shin) (see also hip drop)
• Achilles tendon problems from whiplashAlso caused by ↑ use, tight calves
+ various other problems
© 2015Hitting the Ground
Power Lacing
© 2015Hitting the Ground
Summary
• The Big Forces• Gravity and Momentum
• Elastic Bands and Energy Return
• Posture and Core Control
• Two Arms, Two Legs• Doing the Twist
• Rocking and Rolling
• Hitting the Ground: Crossing Over & Pronation
© 2015
Thank You!
... Any Further Questions?
... Any Desire for Further Workshops?
Practical drills and exercises7pm Thursday 14th May, Coombe Dingle
Contact: Neil Miller neil@coreanalyst.co.uk
www.coreanalyst.co.uk YouTube.com/CoreAnalystTV
facebook.com/CoreAnalystLtd
© 2015
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