This document discusses biomechanics models of human movement. It describes three schools of biomechanics: the inverted pendulum model from 1685, the spring-mass model from 1989/1990, and the integrated spring-mass model from 2012. The spring-mass model views the leg as a spring and torso as mass, while the integrated model also includes the spine and models the legs as progressive rate torsion springs. The document argues the integrated model better explains how the human body absorbs shocks and stores energy for efficiency. It also discusses how nervous system modulation, movement patterns, fatigue and other factors can impact spring stiffness and compliance in the human body.

2. Biomechanics of Human Movement
Two Key Elements
1. How is it engineered?
2. How does it modulate itself?

3. Bob Beamon

4. Barefoot Running

5. Three Schools Of Bio-Mechanics
• Inverted Pendulum Model – and The Rocker-
Lever Series Based Model (1685)
• The Spring- Mass Model (1989/1990)
• The Integrated Spring-Mass Model (2012)

6. Borelli Giovanni Alfonso 1680
Rocker-Based Inverted Pendulum Model
• De Motu Animalium, Pars prima or
On the movement of animals
• In his seventeenth century volume
‘De motu animalium’, Borelli
discussed walking as vaulting over
stiff legs using a pair of compasses
and noted the importance of
rebounding on compliant legs in
running (97).
• From that early account up to the
present, walking and running have
been treated as different mechanical
paradigms, and the two
corresponding models, the inverted
pendulum model for walking (5) (98)

7. Dr. Yuri Verkhoshansky
The Father of Plyometrics 1971

8. Central Institute of Physical Culture
and Sport, Moscow 1989

9. Historic Verkhoshansky
Plyometric Training Videos

10. There is a gap in the way doctors think and do and what
athletes and patients require for top performance

11. Spring-Mass Model
Blickhan 1989; McMahon & Cheng 1990
Harvard University
• The planar spring-mass model is a
simple mathematical model of
bouncing gaits, such as running,
trotting and hopping (105)
• These spring-mass models
embody the observation that
during walking and running, the
leg performs mechanical work
more gently than in the
‘impulsive gaits’ described above,
undergoing some compression
and restitution as if the whole leg
were a linear spring. (15)

12. Spring-Mass Model
vs
Integrated Spring Mass Model
• Lever Defined (Rocker)
A simple machine
consisting of a bar that
pivots on a fixed support,
or fulcrum, and is used to
transmit torque. A force
applied by pushing down
on one end of the lever
results in a force pushing
up at the other end.
• Spring Defined:
In classic physics, a spring
can be seen as a device
that stores potential
energy, specifically elastic
potential energy, by
straining the bonds
between the atoms of an
elastic material.

13. Inverted Pendulum Model vs Spring-Mass Model

14. Inverted Pendulum vs Spring-Mass
Geyer H., Seyfarth A., Blickhan R. 2006 (13)
The basic mechanics of human locomotion
with the Inverted Pendulum model are
associated with vaulting over stiff legs in
walking and rebounding on compliant legs in
running.
For 325 years we have been modeling human
walking as a rocker-lever based Inverted
Pendulum
With a simple bipedal spring-mass model, we
show that not stiff but compliant legs are
essential to obtain the basic walking
mechanics
In fact, they concluded the spring-mass model
was best for describing the walking gait

15. Key Argument
• The Integrated Spring-Mass model
protects the body from impacts and
injuries
• The human spring stores mechanical
energy therefore it is an efficiency
mechanism.
• Rocker-Lever Based Model cannot explain
either of these important factors

16. Spring-Mass Model
vs
Integrated Spring-Mass Model
• These spring-mass models embody the
observation that during walking and
running, the leg performs mechanical
work more gently than in the ‘impulsive
gaits’ described above, undergoing
some compression and restitution as if
the whole leg were a linear spring. (15)
• The Spring-Mass Model embodies
that during walking and running, the
whole leg were a linear spring. (15)
• The Integrated Spring Mass Model
represents the “human spring” as a
progressive rate spring because the
majority of spring energy is absorbed
in the lower body.

17. Spring-Mass Model
• The Spring-Mass Model
models the legs as springs
and the torso as the mass
• The Spring-Mass Model
does not model the arch
of the foot
• The Spring-Mass Model
does not model the spine

18. Integrated Spring-Mass Model
• Transient vibrations caused by
heel strike and travelling
vertically through the body have
been monitored using
accelerometers taped to the skin.
(151)
• This velocity is greatest in the
legs, 610 m/s, and least in the
spine, 90 m/s. Shock absorption
occurs mainly in the legs and to a
lesser degree in the spine. (151)
• We integrated the spine into the
model

19. Integrated Spring-Mass Model
• Integrated Spring-Mass
Model suggests the legs are
the combination of a
Progressive Rate Spring and
Torsion Spring
• This new model models the
legs as Progressive Rate
Torsion Springs the body as
a Progressive Rate Spring
and Torsion Spring.
• The head is the only mass

20. Integrated Spring-Mass Model
Models the Arch as a Spring Suspension System

21. Spring Mechanics - Hookes Law

22. SPRING LOADING

23. Potential Energy of Springs

24. ELASTIC DEFORMITY
This type of deformation is reversible. Once the forces
are no longer applied, the object returns to its original
shape.
The ability of the spring to deform, store energy,
reform to its exact original shape, releasing energy.
THE ABILITY OF THE SPRING TO DEFORM, STORE
ENERGY, REFORM TO ITS EXACT ORIGINAL SHAPE,
RELEASING ENERGY
This is the key principle behind maximum recoil,
injury prevention and reduced aging
Journal of Applied Physics, M. Mooney, September 1940, Volume: 11 Issue 9 Page (s) 582 - 592

25. ELASTIC DEFORMITY VS
PLASTIC DEFORMITY
• ELASTIC
DEFORMITY
• YIELD STRENGTH
• ULTIMATE
STRENGTH
• FAILURE
STRENGTH

26. PLASTIC DEFORMITY
In physics and materials science, plasticity describes the deformation of a material
undergoing non-reversable changes of the shape in response to applied forces.
The human spring deforms, stores energy, DOES NOT RETURN TO ITS EXACT
ORIGINAL SHAPE, RELEASES LESS ENERGY
This can happen 2 ways:
1. It can happen instantly as in a herniated disc
2. It can happen many years
10,000 steps/day x 365 days/year = 3,650,000
Walking for 30 years 3,650,000 x 30 = 109,500,000 collisions
The life expectancy of a Malaysian male is 74.84 years
Average Malaysian Male collides with the earth 273,000,000 times in a lifetime
J. Lubliner, 2008, Plasticity theory, Dover, ISBN 0-486-46290-0, ISBN 978-0-486-46290-5.

27. In vivo behaviour of human muscle tendon during walking.
Department of Life Sciences, University of Tokyo, Meguro, Japan.
T. Fukunaga
• The study we investigated in vivo length
changes in the fascicles and tendon of the
human gastrocnemius medialis (GM) muscle
during walking. (67)
Two important features emerged:
• The muscle contracted near-isometrically in
the stance phase, with the fascicles
operating at ca. 50 mm
• The tendon stretched by ca. 7 mm during
single support, and recoiled in push-off.
• The gastrocnemius does not push the body
forward. It springs it forward.
• The muscle contraction was primarily for
stabilizing the foot, leg and knee position.
(67) (138)

28. What Do The Muscles Do?
• Although some of this
work can be provided
passively by elastic
energy storage in
tendons (136) (137),
active muscles provide
the force necessary to
support the body and
maintain tension on
tendon springs.

29. Spring Modulation or Spring Control
Nervous System
• Sensory Receptors - Sensory information from a
number of sources is instrumental in the control and
sensation of movement. These special receptor cells
include muscle spindles (2) Golgi tendon reflex cells
(3), joint receptors, (4) skin receptors, (5) visual and
balance control or vestibular receptors (6) (7) (8) (9)
and receptors that control the flow of blood through
your circulatory system and respiratory system through
or the control of your rib cage spring (9)
– Muscle Spindle Cells

30. Sensory for Spring Modulation
Muscle Spindle Cell Golgi Reflex Organ

31. Increase Depth of Loading
Maximum Protection and Efficiency

32. LANDING MUSCLES
SPRING SUSPENSION SYSTEM MUSCLES

33. GAIT ANAYSIS

34. RETRAINING
ABNORMAL MOVEMENT PATTERNS
RUNNING-WALKING FORM & TECHNIQUE
TRAINING INVOLVES REPEATED MOVEMENTS
TO STORE PATTERNS

36. ELASTIC DEFORMITY
VS
PLASTIC DEFORMITY
YIELD STRENGTH
• Beyond the elastic limit, permanent
deformation will occur.
• The lowest stress at which permanent
deformation can be measured.
G. Dieter, Mechanical Metallurgy, McGraw-Hill, 1986
Flinn, Richard A.; Trojan, Paul K. (1975). Engineering Materials and their Applications.
Boston: Houghton Mifflin Company. p. 61. ISBN 0-395-18916-0.

37. What Causes Stiffness In The Spring?
Damaging Tension in the Spring
Three Causes Of Preload Muscular Tension:
• Abnormal Movement Patterns from tension
created by neuromuscular reflexes
• Mental Stress
• Form And Technique Breaks
– Reciprocal Inhibition
• You see more muscular coactivation with age

38. Nervous System Over Modulation
Internal Compressive Forces on the Spring Mechanism
• Stiffness in the spring follows
patterns according to the pattern
of the gait
• Painful compressive spasms and
non painful compressive spasms
(latent) link.
• Both compress the spring from
toe to head.
• They are discovered with deep
palpation.
• Sonoelastography

39. What causes overmodulation
• The author proposes that central nervous system-
maintained global changes in α-motoneuron function,
resulting from sustained plateau depolarization, rather
than a local dysfunction of the motor endplate,
underlie the pathogenesis of spasms. (582)
• These results suggest a mechanism by which
emotional factors influence muscle pain. (566)
• Any low-level contractions, can lead to pressure
increases in intramuscular pressure especially near the
muscle insertions, which may impair the local
circulation, cause hypoxia, and eventually lead to
trigger point formation. (617) Muscular strain is one of
the reasons for myofascial syndrome (503)

40. Neuromotor Reflex

41. Compressive Forces

42. Preventive Medicine
Is not working

43. Non-Sport Causes of
Muscle Stiffness in the Spring
• Sleeping – postures that are not
completely horizontal
• Sitting – maintaining bodyparts
outside of perpendicular or
horizontal
– 20 minutes in one place
• Standing – standing in one place too
long
• Visual Stressors
• Mental Stressors
• Inflammation invading sensory cells
(413)

44. Trigger Points vs Painful Muscle Contractions
• These results suggest that latent trigger points could be involved
in the genesis of muscle cramps. Focal increase in nociceptive
sensitivity at trigger points constitutes one of the mechanisms
underlying muscle cramps. (636)
• Measurable sources of muscle tension include viscoelastic tone,
physiological contracture (neither of which involve motor unit
action potentials), voluntary contraction, and muscle spasm
(which we define as involuntary muscle contraction). (636)
• Localized muscle cramps may induce intramuscular hypoxia,
increased concentrations of algesic substances and direct
mechanical stimulation of nociceptors and pain. (636)

46. STEP ONE
Release The Spring
• Another component of
the total mechanical work
is the internal work,
which is needed to
reciprocally accelerate
body segments with
respect to the body
centre of mass and to
overcome internal friction
in body tissues (Fenn,
1930). (135)

47. Treating the Spasms
• Botox
– Acetylcholine
• Dry Needling
• Acupuncture
• Deep Tissue
• Increases pressure short term
• Decreases pressure long term
• Pushes Inflammation out

48. Foot and Ankle Adjustment

49. Muscle Spindle Cell Inflammation
Muscle Spindle Cell Muscle Spindle Cell Inflammation

50. Relax to Maximize Depth of Safe Loading
Elastic Spring Elements to do the Work
• The ability to relax muscle is very important for rapid movements
especially in cyclical actions, which involve recent assists of ATP during
the phases between muscle contractions.
• The adequate retrieval of elastic energy stored in the muscle complex,
together with the stretch–shortening potential of force output, or
valuable prerequisites for efficient high velocity cyclic and acyclic
movement.
• Verhkoshanski 1996 reports that economical sprinting activity can
result in the recovery of about 60% of total mechanical energy
expended in the movement cycle, with the remaining 40% being
• He had set a high correlation between the muscular capacity to store
potential elastic energy and the performance of distance runners, with
an increase in the contribution from non-metabolic energy sources
taking place with increased in running velocity
Verkhoshansky YV (1996) Quickness and velocity in sports movements IAAF Quarterly New
Studies in Athletics 11 (2-3); 29-37

51. Changes in Spring Stiffness with Fatigue
• Increased Significantly With Fatigue
•
• Mean Contact Area (Foot To Ground),
• Contact Time
• Peak Vertical Ground Reaction Force
• Centre Of Mass Vertical Displacement
• Leg Compression
•
• Decreased
•
• Flight Time
• Leg Stiffness
• Mean Pressure

52. What Determines Limb Stiffness?
– Overall limb stiffness (i.e. leg stiffness)
– Single joint stiffness (i.e. ankle stiffness)
– Muscle tendon unit stiffness (i.e. medial
gastrocnemius and Achilles acting together)
– Individual tissue stiffness (i.e. Achilles tendon)
– Individual fibre stiffness (i.e. single muscle fibre)
(58)
– Cellular Stiffness

53. Biomechanists designate three types of stiffness which can be
calculated, the type used will be dependent on the task and
system level to be analysed.
• Vertical stiffness (kvert) – used to determine limb stiffness
during vertical tasks (i.e. jumping and hopping in place)
• Leg stiffness (kleg) – used to determine limb stiffness
during horizontal (i.e. running, jumping and bounding) as
well as vertical tasks
• Torsional stiffness (kjoint) – used to determine joint
stiffness (important as these forces are now acting
rotationally as opposed to linearly)

54. Leg Spring Stiffness
Based on a spring-mass model, leg spring stiffness, which is defined as the
ratio of maximum ground reaction force to maximum center of mass
displacement at the middle of the stance phase, was calculated using the
vertical ground reaction force.
Although the human leg is very complicated, when it is supporting a runner, it
behaves very much like a coiled spring. When the spring is compressed, it
pushes back against the compression with a force that force is proportional to
the distance of compression. The amount of force divided by the compression
distance is the spring constant or, in this case, the Leg Stiffness.
• Leg stiffness (kleg) is the ratio of peak vertical force and the change in
length of the leg spring
• Leg spring stiffness is not the same thing as stiffness in the legs. Stiffness
in the legs effects spring stiffness.

55. Spring Stiffness

56. Spring Compliance

57. Spring Compliance VS Spring Stiffness

58. Spring Stiffness vs Spring Compliance
Which is better?
Spring Compliance
• A compliant landing strategy
led to over a 37% more
negative collision work than
necessary. (117)
• Compliant landing strategy
improved impact resistance.
• A compliant landing strategy
leads to a less efficient gait,
slower speeds and reduced
joint stability.
Spring Stiffness
• Increased Spring Stiffness
leads to a more efficient gait
• Stiff landing strategy reduced
impact resistance
• Increased spring stiffness
improves joint stability (94)
• Increased spring stiffness leads
to increased speed (62)

59. Usain Bold Technique

60. Spring Suspension System Release

61. Metatarsal Cunieform Joint
Arch Release

62. Metatarsal Cunieform Joint
Arch Release

63. Arch and Ankle Release

64. Toe, Foot and Ankle Stretch

65. Release Locked Spring

67. STEP THREE
STRENGTHEN THE
HUMAN SPRING SPRING SYSTEM
BAREFOOT RUNNING
JUMPING DRILLS
PLOMETRICS

68. ACCELERATION LANDING

69. DECELERATION LANDING

70. NEUTRAL LANDING

71. BANG AND TWIST WALKING
VS
SPRING AND ROLL WALKING

72. Footwear & Running Surface
Muscle Stiffness Tuning
• It has been frequently reported that
vertical impact force peaks during
running change only minimally when
changing the midsole hardness of
running shoes.
• It was possible to produce the same
impact force peaks altering specific
mechanical properties of the system
for a soft and a hard shoe sole.
• Therefore, it has been concluded that
changes in muscle activity (muscle
tuning) can be used as a possible
strategy to affect vertical impact
force peaks during running.

73. STEP TWO
STRENGTHEN THE
HUMAN SPRING LEVER SYSTEM
RESISTANCE EXERCISES
SPRING SUSPENSION MUSCLES

76. LEVER EXERCISE
RESISTANCE EXERCISE

77. Release The Abnormal Internal Compressive Force
Joint Play Release

78. Increase Depth Of Loading Of Forces
Into The Human Spring
• Dynamic Plyometric-Impact Stretching
• Plyometric impulsive stretching, which involves rapid termination
of eccentric loading followed by a brief isometric phase and an
explosive rebound belying and stored elastic energy and
powerful reflex muscle contraction.
• This stretch shortening action is not intended to increase range
of motion, but to use specific stretching phenomena and to
increase speed strength of movement for a specific sporting
purpose.
Mel Siff, Yuri Verhkoshansky, Supertraining, Supertraining International Denver USA 1999

79. Steps to Increasing
Impact Protection and Energy Recycling
• Release The Abnormal Internal Compressive Force On
The Human Spring
• Increase Depth Of Loading Of Forces Into The Human
Spring
• Strengthen The Spring Suspension System via Lever
Strengthening
• Strengthen The Spring Suspension System via Spring
Strengthening
• Maintain

81. Current Standard of Care

82. Abebe Bikila
1960 & 1964 Olympic Champion

83. Recycling of Energy
• 1964 - The efficiency in running has been
calculated as about 40–50%: this appears
to be identified as elastic recoil energy
from the stretched contracted muscle.
(136)
• 1977 - This transfer is greatest at
intermediate walking speeds and can
account for up to 70% of the total energy
changes taking place within a stride,
leaving only 30% to be supplied by
muscles. (53)
• 1987 - Kinetic and potential energy
removed from the body in the first half of
the stance phase is stored briefly as elastic
strain energy and then returned in the
second half by elastic recoil. For example,
empirical data show substantial
deformations of the foot arch (148) (149)

84. Treatment of Muscle Spasms that Preload the Spring
Protection and Energy Recycling Mechanisms
• Muscle spindles which detect changes in muscle fiber length and rate
of change of length.
• Golgi tendon organs which monitor the tension and muscle tendon
during muscle contraction or stretching

85. Improved Stiffness
• Stiffness is an important parameter because we take advantage of the storage
and release of elastic energy in the musculotendinous unit to improve muscle
power and jump height. (51)
• However, elastic energy storage is likely to be greater in those with more
compliant muscle–tendon units, which seems important for jump success. (51)
• Stiffness is an important parameter because we take advantage of the storage
and release of elastic energy in the musculotendinous unit to improve muscle
power and jump height. (51)
• So release joint and muscle stiffness increases compliance, improves elastic
loading and increases potential stiffness.
• Training the abdominals from all 6 directions improves spring stiffness and
efficiency. (26)

86. PLYOMETRICS
Free Stored Elastic Energy
The ability to use stored elastic energy depends on the
• The velocity of stretching
• the magnitude of the stretch
• the duration of the transition between the termination of the eccentric and
initiation of the concentric phase of the movement.
This delay between the two phases should be minimal or the stored elastic energy
will be rapidly dissipated.
Because a more prolonged delay will allow fewer cross bridges to remain attached
after the stretch (Edman Et Al 1976)
The greater the velocity of stretching it during the eccentric contraction, the
greater the storage of elastic energy (Rack & Westbury 1974)

87. Running Drills

88. Double Leg Drills

89. Single Leg Drills

90. Usain Bolt Breaks World Record

91. Thank you!