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The role of arm mechanics during sprint-running: a review of the literature and practical applications

April 2018
Strength & Conditioning Journal 40(5):1

DOI:10.1519/SSC.0000000000000391

Authors:

Paul Macadam

None

John Cronin

Auckland University of Technology

Aaron Uthoff

Auckland University of Technology

Michael Johnston

Swansea University

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The importance of arm action during sprint-running has been an ongoing discussion among practitioners. Though some coaches believe the arms serve to merely provide balance to the rotary momentum of the legs, others believe the arms are vital to sprint-running performance and contribute to propulsive forces. Though a large body of research has been undertaken into the effects of leg kinematics and kinetics on sprint-running performance, the role of arm action remains ambiguous and under investigated. Therefore, the purpose of this review was to improve understanding related to arm mechanics during sprint-running and provide practical context guidelines

Shoulder asymmetry assessment during standing arm drive. (A) neutral shoulders. (B) elevated left shoulder.

…

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Role of Arm Mechanics

During Sprint Running:

A Review of the

Literature and Practical

Applications

Paul Macadam, MSE,

John B. Cronin, PhD,

1,2

Aaron M. Uthoff, MSc, CSCS,

Michael Johnston, PhD,

3,4

and Axel J. Knicker, PhD

Sports Performance Research Institute New Zealand (SPRINZ) at AUT Millennium, Auckland University of

Technology, Auckland, New Zealand;

School of Exercise, Biomedical and Health Sciences, Edith Cowan

University, Perth, Australia;

British Athletics, National Performance Institute, Loughborough University,

Loughborough, United Kingdom;

A-STEM, Swansea University, Swansea, United Kingdom; and

Institute of

Movement and Neuroscience, Research Centre for Neuromechanics and Neuroplasticity, German Sport

University, Cologne, Germany

ABSTRACT

THE IMPORTANCE OF ARM

ACTION DURING SPRINT RUN-

NING HAS BEEN AN ONGOING

DISCUSSION AMONG PRACTI-

TIONERS. ALTHOUGH SOME

COACHES BELIEVE THAT THE

ARMS SERVE TO MERELY PRO-

VIDE BALANCE TO THE ROTARY

MOMENTUM OF THE LEGS,

OTHERS BELIEVE THAT THE

ARMS ARE VITAL TO SPRINT

RUNNING PERFORMANCE AND

CONTRIBUTE TO PROPULSIVE

FORCES. ALTHOUGH A LARGE

BODY OF RESEARCH HAS BEEN

UNDERTAKEN INTO THE EF-

FECTS OF LEG KINEMATICS AND

KINETICS ON SPRINT RUNNING

PERFORMANCE, THE ROLE OF

ARM ACTION REMAINS AMBIGU-

OUS AND UNDERINVESTIGATED.

THEREFORE, THE PURPOSE OF

THIS REVIEW IS TO IMPROVE

UNDERSTANDING RELATED TO

ARM MECHANICS DURING

SPRINT RUNNING AND PROVIDE

PRACTICAL CONTEXT GUIDE-

LINES.

INTRODUCTION

Arm swing is a distinctive char-

acteristic of sprint running with

the arms working in a contralat-

eral manner with the legs to propel the

body in a horizontal direction. To

achieve high acceleration and maxi-

mum velocity, the arm-leg movements

have to be coordinated (19). To date,

a large body of research has been

undertaken into the effects of lower-

limb kinematics and kinetics on sprint

running performance (16,20,23,26,27).

A systematic literature review found

a strong relationship between lower-

limb strength and sprint running per-

formance (33); however, the role of

arm action and subsequent strengthen-

ing remains ambiguous and underin-

vestigated. Because sprint running

has distinctive phases (i.e., start,

acceleration, and maximum velocity)

and the body’s position varies through-

out these phases, it is quite likely that

the role of the arms may

change in accordance with these

phases (Figure 1). Furthermore, in team

sport events, different starting positions

are used to optimize sprint performance,

for example, a crouch start (American

football, track and ﬁeld running) or

a standing start (soccer, rugby, and bas-

ketball) (36). Figure 2 highlights the dif-

ference between body and arm positions

during a block, 2-point contact, and 3-

point contact positions.

Given that evidence is limited on how

arm contribution affects track and

sport speed, understanding and reﬁn-

ing the role of the arm during the dif-

ferent phases of sprint running would

seem important due to the potential to

improve performance outcomes. The

Address correspondence to Paul Macadam,

paul.macadam@gmail.com.

KEY WORDS:

acceleration; kinematics; kinetics;

maximum velocity; sport-speciﬁcity;

upper limbs

purpose of this review, therefore, is

to improve understanding related to

arm mechanics during sprint running

and provide guidelines on how this

information may be used in a practical

context. Peer-reviewed journal articles

were retrieved from electronic

searches of ScienceDirect, Web of Sci-

ence, PubMed, Google Scholar, and

SPORTDiscus databases, in addition

to relevant bibliographic hand

searches with articles limited to

English language. The search strategy

included the terms arm, upper limb,

sprint, run, acceleration, and velocity.

The month of the last search per-

formed was September 2017. Articles

that discussed the role of the arms dur-

ing sprint running performance were

considered eligible for this review.

Due to the small amount of research

in sprint running in this area, articles

that assessed arm action during

running were also included in the dis-

cussion. A total of 28 studies met the

inclusion criteria for this review.

THE ROLE OF THE ARMS DURING

RUNNING AND SPRINT RUNNING

The importance of the arms during

running has been highlighted by

Egbuonu et al. (7) who reported a 4%

increase in the energetic cost of tread-

mill running without arm swing (i.e.,

arms held behind the back). Similarly,

treadmill running with the arms

crossed in front of the chest resulted

in a signiﬁcant increase (8%) in the

net metabolic power demand com-

pared with running with arm swing

(2). Moreover, running without arm

swing did not change the average step

width but signiﬁcantly increased step

width variability (9%) and step fre-

quency (2.5%) compared with running

with arm swing (2).

Regarding sprint running, the role and

importance of arm action during sprint

running has been an ongoing discus-

sion among researchers for several

decades. For example, Bosch and

Klomp (4) suggested that arm action

during sprint running had a greater

function than merely maintaining bal-

ance or compensating for the small dis-

turbances in body posture. The arm

action was thought to contribute to

an increase in velocity by the develop-

ment of an increased thrust in the

direction of progression (4), which

has particular importance for the start

and acceleration phase. When the

body is upright during maximum-

velocity sprint running, Bunn (6) and

Hay (10) proposed that the arms

served as a balancing action for the

hips, whereas during running, Hopper

(15) proposed that the main function of

the arm swing was to help lift the

Figure 1. Start phase (A) and maximum velocity phase (B) sprint running.

Figure 2. Block (A), 2-point contact (B), and 3-point contact (C) start positions.

Role of Arm Mechanics During Sprint Running

VOLUME 00 | NUMBER 00 | MONTH 2018

runner off the ground. Sayers (31) sug-

gested that the arm drive had 2 main

purposes: (a) to increase both stride rate

and ground reaction forces, and, (b) to

improve balance by countering the

body’s rotation initiated by the pelvis.

Given the different point of views on

the contribution of the arms to sprint

running, the following sections discuss

the start and acceleration phase and

maximum velocity phase separately.

START AND ACCELERATION

PHASE

During the start of the sprint, the

body’s center of mass leans forward,

suggesting that the relative momentum

of the horizontal component of both

arms may not be canceled (28). Schnier

(32) and Embling (8) proposed that

a vigorous arm action would assist for-

ward drive during the start of a sprint.

It would seem that for the start and

early acceleration phases at the very

least, that understanding the impor-

tance of arm action may beneﬁt sprint

running performance.

At the beginning of the pushing phase

during 10-m sprints from a block start,

the joint angular velocity of the rear

shoulder was linked to an extension

movement that is mainly related with

the raising of the thorax (35). It is

thought that the hands have an action

on the ground, which is associated

with the shoulder joint angular velocity

because of this extension movement

(35). After a block start, Lockie et al.

(19) reported ﬂexion-extension joint

range of motion (ROM) for the shoul-

der (45.6–52.58and 46.4–55.08, ﬁrst and

second steps, respectively) and the

elbow (53.8–66.38and 56.9–67.38, ﬁrst

and second steps, respectively) in foot-

ball players, with the authors noting

small shoulder ﬂexion (,308) may

relate to the subject’s lack of proper

sprint technique. During early sprint

acceleration, the ﬂexion and extension

angular velocity of the humerothoracic

joint is high (approximately 7008/s)

(35), indicating that the ROM of the

scapulothoracic joint is important dur-

ing sprint running. Slawinski et al. (35)

reported that a greater variance in joint

angular velocity was found in the arms

compared with the legs, which may be

related to individual morphological

properties and starting techniques.

The importance of scapulothoracic

joint ROM is highlighted when arm

drive motion was restricted by con-

straining scapular motion with tape,

step length (24.6%) and whole body

lean position (23.9%) during the ﬁrst

step was signiﬁcantly decreased, subse-

quently reducing the sprinting speed

(23.2%) (28). Furthermore, Otsuka

et al. (28) found that the forward lean-

ing position of center of mass (23.9%)

Figure 3. Wearable resistance forearm loading.

Figure 4. Sled-resisted sprint running with wearable resistance.

Strength and Conditioning Journal | www.nsca-scj.com 3

and the ROM of humerothoracic

extension (25.2%) were signiﬁcantly

smaller than that in the free condition.

These changes in forward lean are of

interest, given that Kugler and Janshen

(18) reported higher horizontal accel-

erations were generated by more for-

ward leaning of the body at take-off,

suggesting that the forward leaning

position of the center of mass at take-

off is important for enhancing sprint

speed and undoubtedly the arms con-

tribute to this position.

Bhowmick and Bhattacharyya (3) pro-

posed that the horizontal acceleration

of the arm swing may assist in increas-

ing stride length. Moreover, the au-

thors suggested that during the start

of a sprint, the vertical component of

the arm movement may create a situa-

tion for enhanced leg drive during

ground contact, and therefore helps

to increase the forward velocity of

the main movement indirectly (3). As

previously mentioned by Lockie et al.

(19), arm-leg coordination is required

to optimize sprint running perfor-

mance. This proposal is supported by

Slawinski et al. (35) who reported that

in elite sprinters, a greater synchroni-

zation between the arm-leg increased

the efﬁciency of pushing on the blocks

from a sprint start. During 10-m sprint

running from a block start, it was found

that although the leg and head-trunk

segments contributed the greatest pro-

portion of kinetic energy of the total

body, the arms still contributed 22%

of the body’s kinetic energy, indicative

of the importance of these segments

during the pushing phase of the block

start (35). Slawinski et al. (34) also

investigated the initial 2 steps after

a block start and found that elite

sprinters had the ability to move their

center of mass further forward than

well-trained sprinters partially due to

the movement of their arms.

Although block starts are used in

sprint races up to 400 m, athletes will

often practice from a standing position,

whereas team sports require athletes to

sprint from an upright position (21).

Although research has investigated

acceleration performance from a stand-

ing start, no authors have examined the

contribution of the arms during this

start position and how they differ from

a block start. Salo and Bezodis (30)

found that in using a split-stance stand-

ing start, an athlete is able to increase

acceleration in the initial phase of the

sprint to a greater extent than in block

start. In a standing start, the distance

between the front and rear foot is nat-

urally long, causing the athlete to push

Figure 5. Medicine ball ﬁrst step release.

Figure 6. Plate overhead step up.

Role of Arm Mechanics During Sprint Running

VOLUME 00 | NUMBER 00 | MONTH 2018

for longer on the front foot once the

rear foot has cleared the ground (30).

Majumdar and Robergs (21) noted that

during the acceleration phase, it was

important to orient the body so that

the location of the body’s center of

mass and the center of gravity is as

forward as possible to allow for contin-

ued forward acceleration. Given the

body’s change in orientation during

the transition through the acceleration

phase, future research is required into

how changes in arm action from

a standing start can contribute to

enhancing start and acceleration phase

performance.

MAXIMUM VELOCITY PHASE

During the maximum velocity phase,

the body is upright, and the momen-

tum of the horizontal component of

the arm is not directly associated with

the body’s center of mass as the swing-

ing backward and forward motions of

the arms are in opposite directions and

the momentum is canceled (11,14).

Two-dimensional quantitative studies

by Mann (22) and Mann and Herman

(23) found that there was a minimal

amount of muscular contribution from

the shoulder and elbow joints during

the maximum velocity phase of sprint

running. Mann and Herman (23)

compared the performance of the

ﬁrst- and eighth-place sprinter during

the maximum velocity phase of a 200-

m race. The faster sprinter had a greater

arm displacement from the shoulder

(1358versus 1188) and elbow (848ver-

sus 678) joints with a greater average

speed from the shoulder (5258/s versus

4908/s) (23). From the analysis of mus-

cle moments from 15 sprinters who

ranged in experience from collegiate

to world class, Mann (22) proposed

that activity from the shoulder joint

related to maintaining balance, and

activity from the elbow indicates that

its purpose is to maintain the forearm

in a ﬂexed position; however, the opti-

mum positions are yet to be estab-

lished. Furthermore, it was suggested

that no relationship existed between

arm action and sprint running perfor-

mance (22). Consequently, the authors

suggested that the role of the arms dur-

ing sprint running was to maintain bal-

ance (22,23). However, due to the

limited number of subjects and the dif-

ference in their levels of sprint running

experience, understanding arm action

during the maximum velocity phase

clearly requires further research.

Researchers analyzing the effects

of arm swing during treadmill

running using 3-dimensional motion

analysis found that the vertical ROM

of the body center of mass was

increased 5–10% by arm swing (14).

The authors proposed that the primary

lift mechanism occurs during the mid-

contact phase whereby the upward

acceleration of the arms, relative to

the trunk, produces a greater vertical

impulse on the body as a whole (14).

The lift provided by the arms was

found to increase as running speeds

increased, therefore highlighting their

potential importance at higher sprint

running speeds. This ﬁnding may be

of signiﬁcance during the start phase

as Young et al. (38) reported that when

the body has a signiﬁcant forward lean,

the vertical lift provided by the arm

drive has a horizontal propulsive

component. Hinrichs et al. (13) re-

ported that the arms were involved

in reducing total-body angular

momentum about a vertical axis

through the body’s center of mass

when running in an upright position.

However, Hinrichs (12) reported that

the arms possess the potential to

compensate for each other and for

asymmetries elsewhere in the body

during treadmill running. Bunn (6)

suggested that a vigorous backswing

of the arms caused an increased leg

stride and assisted to maintain veloc-

ity when the legs fatigued. More

research into the role of the arms dur-

ing the maximum velocity phase is

required coupled with understanding

the transition through all phases of

sprint running.

Figure 7. Standing transition arm drive.

Strength and Conditioning Journal | www.nsca-scj.com 5

TRAINING STRATEGIES FOR ARM

DRIVE

Although coaches believe that the arms

play a vital role in sprint running (17,37),

the training strategies to improve arm

mechanics for sprint running remain rel-

atively unexplored. Young et al. (38) pro-

posed that the muscles that drive the

arms may be relatively more important

for short sprints. However, although the

standing and seated arm swing exercises

are commonly implemented to enable an

athlete to focus on the actions of the

upper limbs (5), only a few researchers

have speciﬁcally investigated the effects

of training interventions on arm mechan-

ics for sprint running. This section dis-

cusses the ﬁndings of these articles in

relation to the start and acceleration, as

well as the maximum velocity phase.

START AND ACCELERATION

PHASE

Acute changes were examined during

40-m overground sprint running with

wearable resistance of 0.5 kg attached

to each arm using a weighted sleeve on

10 male recreationally trained athletes

from ﬁeld-based sporting clubs (25).

No signiﬁcant differences were found

at the start phase between loaded and

unloaded conditions in 10-m best time

(20.4%) and 10-m average time

(21%), with Cohen effect sizes trivial

(,0.2) for both changes (25). The loads

were positioned on the dorsal side of

the forearm, held to the arm by an

elastic sleeve extending from the wrist

to above the elbow, and secured with

velcro straps. Subject’s body mass

(BM) was not reported; therefore, the

magnitude of this load as a percentage

of BM was unknown. McNaughton

and Kelly (25) proposed that as no det-

rimental effects were found in perfor-

mance, the forearm loads may provide

a suitable overload stimulus during

speed training sessions without nega-

tively impacting technique or perfor-

mance. An earlier study on 24 male

physical education students used loads

of 0.2, 0.4, and 0.6 kg (0.3–0.9% BM)

lead rods, held in each hand, during 30-

m over the ground sprint running (29).

Similarly, Ropret et al. (29) reported no

changes in velocity, stride rate, or stride

length with any loaded condition over

the initial 15 m compared with the un-

loaded sprint. From these ﬁndings, it

may be concluded: (a) that arm loads

Figure 8. Double-arm pillar press.

Role of Arm Mechanics During Sprint Running

VOLUME 00 | NUMBER 00 | MONTH 2018

of #0.6 kg do not seem to interrupt

spatiotemporal variables and hence

introduce technique breakdown, (b)

preference would be to afﬁx load to

the lower area of the arms, which in-

creases the rotational inertia and en-

sures that the hands are not gripping

a load, which may increase unwanted

tension in the arm and shoulders, and,

loads used in the aforementioned stud-

ies may not have been sufﬁcient to sig-

niﬁcantly overload arm mechanics

during the initial 15 m, and future

research with heavier wearable resis-

tance is required.

When sprint running was performed

with a sled resistance, the athlete’s

body position was forced into an

increased forward lean (19,24). Conse-

quently, Lockie et al. (19) reported that

athlete’s arm drive exhibited a greater

range of shoulder joint ﬂexion over the

initial 2 steps (;2–38) after an 8-week

sled training study. As athletes are cued

at the start of the sprint to take-off

in a more horizontal position,

sled-resisted sprint running with 20%

BM resulted in a 9% more horizontal

take-off angle from a block start (24).

Therefore, the subsequent forward lean

position achieved with sled-resisted

sprint running partly mirrors the start

phase of a sprint and may be an effec-

tive training modality for practitioners

seeking changes in early sprint arm

drive kinematics. Whether this is the

case, especially because the arms are

not directly overloaded, needs to be

investigated further.

MAXIMUM VELOCITY PHASE

During the maximum velocity phase,

sprint running with a loaded arm con-

dition of 0.5 kg per arm had no signif-

icant effect on 40-m best time (20.2%)

and 40-m average time (20.2%), with

Cohen effect sizes trivial (,0.04) for

both changes (25). Moreover, no sig-

niﬁcant effect was found for average

velocity (20.5%, effect size 50.08)

(25). Ropret et al. (29) reported that

no acute effects were found in sprint

performance over 15–30 m until the

heavier loads (0.6 kg, 0.9% BM) were

used, which resulted in a signiﬁcant 1%

decrease in velocity between the un-

loaded and handheld loaded sprint

conditions. No signiﬁcant changes

were found in stride frequency or stride

length during the maximum velocity

phase, although stride length was

reduced ;3 cm with the 0.6 kg loaded

condition (29). A dearth of quantitative

research exists relating to the optimum

mechanics of the arms during sprint

running. Moreover, from qualitative

research, coaches believed that arm

mechanics differ between the maxi-

mum velocity phase and the earlier

phases of sprint running. Coaches

identiﬁed that the arms assist in stabi-

lizing the trunk, and work in tandem

with the legs to stabilize and balance

the body when an athlete is upright

and maintaining maximum speed (17).

PRACTICAL APPLICATIONS

Although coaches recognize the

importance of the arm drive in sprint

running, the role of the arms during

the different phases of the sprint, and

the training of the arms has not been

Figure 9. Single-arm pillar press.

Strength and Conditioning Journal | www.nsca-scj.com 7

articulated to any great detail. This

review attempted to synthesize the avail-

able information by ﬁrst enhancing the

understanding of the role of the arms

during the start and acceleration versus

the maximum velocity phases of sprint

running. By understanding these differ-

ential roles and subsequent mechanics,

programing needs to become clearer.

The following section describes a small

selection of exercises that may assist the

practitioner in the training of the arms

speciﬁc to the phase of sprinting.

START AND ACCELERATION

PHASE

Two previous sprint running studies that

used loads attached to the arms or

hands were found to not overly

alter the spatiotemporal variables.

Therefore, sprint running with wearable

resistance attached to the arms (Figure 3)

may be a suitable training stimulus with-

out unduly affecting start and accelera-

tion kinematics, which may lead to

positive performance adaptations. Wear-

able resistance attached to the forearms

may create a greater horizontal propul-

sion at take-off due to the greater

amount of rotational inertia from the dis-

tal loading of the arms.

Due to the orientation of body (i.e., more

of a horizontal lean) during the start

phase, the vertical lift provided by the

arm drive has a horizontal propulsive

component, and therefore, optimizing

arm action may enable a greater horizon-

tal propulsion. At the start of a sprint,

there is a technical emphasis for athletes

to take-off in a more horizontal position.

Moreover, research has found that the

forward leaning position of the center

of mass at take-off is important for

enhancing sprint speed. Therefore, sprint

running training with resisted sleds (Fig-

ure 4) is one modality that enables this

body position to be maintained, which

results in a greater arm drive action from

a larger shoulder joint ROM. Although

there is no direct overload of the arms in

this position, the orientation of the

body may enable a training stimulus for

greater arm velocity and limb coordina-

tion to be achieved. In addition, with

wearable resistance attached to the fore-

arms (Figure 4), an overload of the arm

action can be achieved. However, this

proposal is speculative and future

research is needed to disentangle

whether this type of training has any

effect on arm drive kinematic and kinet-

ics, and therefore, sprint performance.

Future research is required to ﬁnd an

optimum magnitude of wearable resis-

tance because a load too heavy may

result in negative arm kinematics as

the athlete struggles to maintain a high

velocity arm drive. Given the impor-

tance of the arm drive during push-

off and acceleration, practitioners

should focus on arm-leg coordination

and their contralateral positions.

In addition to traditional sprint and

resistance training, a series of

Figure 10. Shoulder asymmetry assessment during standing arm drive. (A) neutral shoulders. (B) elevated left shoulder.

Role of Arm Mechanics During Sprint Running

VOLUME 00 | NUMBER 00 | MONTH 2018

exercises used by coaches to

improve arm drive function and

arm-leg coordination during the

start and acceleration phase are

illustrated in Figures 5–7. The med-

icine ball ﬁrst step release (Figure 5)

is a loaded arm exercise that may be

used to enhance arm drive extension

andpropulsionrequiredduringthe

initial ﬁrst step. The plate loaded

overhead step (Figure 6) may be

used to enhance arm drive to assist

arm-leg coordination and horizontal

propulsion by overloading the shoul-

der and elbow joints in conjunction

with the lower limbs. The standing

transition arm drive (Figure 7) may

be used by coaches to improve arm

drive technique and rate-of-rise

rhythm through transitioning from

the start to maximum velocity phase

by coordinating the timing of the

arms with the change in the body’s

orientation from a leaning forward

position to an upright position. The

reader needs to be cognizant that

there may be limitations to these ex-

ercises because: (a) the upward pro-

pulsion of the ball and plate may

result in signiﬁcant thoracic exten-

sion, (b) the exercises bias vertical

force production, and (c) there is

no counterbalance from (for exam-

ple) the opposite arm.

MAXIMUM VELOCITY PHASE

During the maximum velocity phase

of sprint running, the body is upright.

When sprint running in this position,

the arms contribute to the total ver-

tical propulsive forces applied to the

ground; therefore, optimizing arm

mechanics in symmetry with the legs

should be a consideration for training

planning. Athletes should train to

achieve an effective arm swing that

originates from the shoulder and

has a ﬂexion and extension action at

the shoulder and elbow that is

matching to the ﬂexion and exten-

sion occurring at the ipsilateral

shoulder and hip. The double-arm

pillar press exercise (Figure 8) and

the single-arm version (Figure 9)

can be used to strengthen the

shoulders and triceps. In addition, ex-

ercises similar to those illustrated in

Figures8and9maybeusedtocon-

comitantly reinforce postural integ-

rity, balance, and arm-leg

coordination.

It may be argued that the vertical

plane–only exercises, depicted in

Figures 8–9, are somewhat non-

speciﬁc, given the discussion of the

role of the upper body in maximum-

velocity running. Given such a con-

tention, the utilization of some track

drills to challenge the coordination of

the arms with the trunk and hips

should also be considered to help

identify training needs. For example,

an upright version of the arm drill

(Figure 10)—starting on ﬂat foot and

coming up to plantar ﬂexion—could

demonstrate/challenge asymmetry

from the hip to the shoulder to better

effect. In this example, Figure 10B

clearly demonstrates the impact that

poor function in the left shoulder can

have on the trunk (side ﬂexion) and

the pelvis (left anterior/medial rota-

tion). This in turn may lead to a series

of antirotation trunk and shoulder

mobility exercises with the aim of

improving relative stiffness between

the shoulder and the hip.

CONCLUSIONS

The role of arm drive remains a con-

tentious topic among sprint coaches

and in the published literature.

Although the arms do seem to coun-

terbalance the rotary momentum of

the legs during sprint running, it

would seem that the arms may addi-

tionally have an important role dur-

ing the start and early acceleration

phase of the sprint. Although the

horizontal force capabilities of the

arms are very limited, owing to

the simultaneous forward-backward

action of contralateral arms when

an athlete is upright, due to the early

forward lean position, the relative

momentum of the horizontal com-

ponent of both arms may not be can-

celed. Moreover, the arms may

contribute up to 10% of the total ver-

tical propulsive forces an athlete is

capable of applying to the ground

(14), highlighting the importance of

an efﬁcient arm action. Elite sprinters

exhibitagreaterarm-legsynchroni-

zation, increasing the efﬁciency of

pushing on the blocks; therefore,

optimizing arm mechanics in syn-

ergy with the legs should be a pro-

gramming consideration.

The importance of this arm-leg syn-

chronization is supported in neuro-

science research, where Frigon et al.

(9) demonstrated that rhythmic arm

movement affected reﬂexes in leg

muscles independent of arm position.

Moreover, arm swing frequency also

regulated not only hip-shoulder

interaction at low frequencies but

predominantly ankle-shoulder in-

phase coordination at higher fre-

quencies, suggesting a tight coupling

between arm swing and postural

coordination (1). Although not

related directly to sprint running,

the ﬁndings do suggest that more

research is needed on arm-leg coor-

dination and the effects of training

the arms alone to quantify changes

in sprint performance.

Conﬂicts of Interest and Source of Funding:

The authors report no conﬂicts of interest

and no source of funding.

Paul Macadam

is a PhD candi-

date at Auckland

University of

Technology.

John B. Cronin

is a Professor of

Strength and

Conditioning at

Auckland Uni-

versity of

Tec h no l og y and

holds an adjunct

professorial posi-

tion at Edith Cowan University.

Strength and Conditioning Journal | www.nsca-scj.com 9

Aaron M.

Uthoff is a PhD

candidate at

Auckland Uni-

versity of

Technology.

Michael

Johnston is

Lead Strength

and Conditioning

Coach for the

British Athlet-

ics team.

Axel J. Knicker

is a Senior Lec-

turer of Move-

ment and

Neuroscience at

German Sport

University

Cologne.

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Role of Arm Mechanics During Sprint Running

VOLUME 00 | NUMBER 00 | MONTH 2018

Active Arm Swing During Running Improves Rotational Stability of the Upper Body and Metabolic Energy Efficiency

Article

Full-text available

Feb 2025
ANN BIOMED ENG

Purpose The kinematic benefits of arm swing during running for upper body stability have been previously investigated, while its role in metabolic energy efficiency remains controversial. To address this, this study aimed to test the hypothesis that active arm swing during running reduces both torso angular motion around the longitudinal axis and metabolic energy consumption. Methods We employed forward dynamics musculoskeletal running simulations with different arm conditions to investigate the hypothesis. Full-body musculoskeletal running models, incorporating 150 muscles, were developed using artificial neural network-based running controllers. Three arm conditions were simulated using the running models and controllers: active arm swing, passive arm swing, and fixed arms. Results Our results revealed that the active arm swing model demonstrated the lowest total metabolic energy consumption per traveling distance. The costs of transport were 5.52, 5.73, and 5.82 J/kg-m for active, passive, and fixed arm models, respectively. Interestingly, while metabolic energy consumption in the upper limb muscles was higher during active arm swing, the total energy consumption was lower. Additionally, the longitudinal rotation of the torso was minimal in the active arm swing condition. Conclusion These findings support our hypothesis, demonstrating that active arm swing during running reduces the angular motion of the torso and the metabolic energy consumption. This study provides evidence that arm swing during running is performed actively as an energy-saving mechanism. These results contribute to understanding of running biomechanics and may have implications for performance optimization in sports and rehabilitation settings.

The Association Between Isometric Shoulder Strength and Sports Performances in University Soccer Players: A Cross-Sectional Study

Article

Full-text available

Oct 2024

Background Soccer, a globally popular sport, demands a complex interplay between physical attributes, including speed, agility, power, and endurance. Although lower-body strength and power are often emphasized, the role of upper-body strength, particularly shoulder strength, remains less explored. Given the importance of upper-body movements in activities such as heading, shooting, and defending, understanding the relationship between shoulder strength and soccer performance is crucial. Aims This study aimed to explore any possible correlation between isometric shoulder muscle strength (flexors and extensors) and sports performance (sprint and agility) and to evaluate whether isometric shoulder strength is associated with sports performance in university-level soccer players. Methods A total of 35 male amateur soccer players were recruited, who underwent demographic measurements such as age, height, weight, and body mass index (BMI), and were then subjected to isometric strength assessment of the shoulder flexors and extensors using a handheld dynamometer (HHD). Subsequently, the players' sprint and agility performances were recorded. Appropriate statistical tests were performed on the obtained data. Results The findings revealed a significant negative correlation between shoulder flexor strength and sprinting (r=-0.707, p<0.01) and between shoulder extensor strength and sprinting (r=-0.611, p<0.01). There was no significant correlation between shoulder flexor strength and agility (r=-0.121, p=0.48) or between shoulder extensor strength and agility (r=-0.212, p=0.22). Multiple linear regression analysis revealed that only shoulder flexor strength (β=-0.688, t=-2.651, p=0.01) was found to have statistically significant relationships with sprint performance, explaining 50% of the variance in sprint performance. Conclusions The present study found a negative bidirectional relationship between shoulder muscle strength and sprint performance. Shoulder flexor strength explained 50% of the variance in sprinting performance. This information is useful for physiotherapists, coaches, and trainers to focus on strengthening the shoulder musculature to improve performance.

The use of wearable resistanceand weighted vest for sprintperformance and kinematics:a systematic reviewand meta‑analysis

Article

Full-text available

Mar 2024

Wearable resistance (WR) and weighted vests (WV) can be used in almost all training conditions toenhance sprint performance; however, positioning and additional mass are different in WV and WRstrategies, affecting performance and kinematics differently. We aimed to systematically reviewthe literature, searching for intervention studies that reported the acute or chronic kinematic andperformance impact of WV and WR and comparing them. We analyzed Pubmed, Embase, Scopus, andSPORTDiscuss databases for longitudinal and cross‑over studies investigating sprint performanceor kinematics using an inverse‑variance with a random‑effect method for meta‑analysis. After theeligibility assessment, 25 studies were included in the meta‑analysis. Cross‑over WR and WV studiesfound significantly higher sprint times and higher ground contact times (CT) compared to unloaded(UL) conditions. However, WR presented a lower step frequency (SF) compared to UL, whereas WVpresented a lower step length (SL). Only one study investigated the chronic adaptations for WR,indicating a superiority of the WR group on sprint time compared to the control group. However, nodifference was found chronically for WV regarding sprint time, CT, and flight time (FT). Our findingssuggest that using WV and WR in field sports demonstrates overload sprint gesture through kinematicchanges, however, WR can be more suitable for SF‑reliant athletes and WV for SL‑reliant athletes.Although promising for chronic performance improvement, coaches and athletes should carefullyconsider WV and WR use

Sex Differences and the Relationship Between Athlete Anthropometrics and Long Jump Performance at National Elite Level

Article

Full-text available

Feb 2025

Objectives: Anthropometric characteristics influence performance and development in athletic activities such as long jumping. This study aimed to analyze sex differences in anthropometrics among high-level long jumpers and investigate the relationship between anthropometrics and long jump distance. Methods: During the national championships, body height, mass, segment lengths, and circumferences of 39 male and 22 female competitors were obtained via a stadiometer, weight scale, and non-stretchable tape. Officials measured jump distances during the competition. ANOVA, correlation, and stepwise-forward regression analysis were conducted at a significance level of p < 0.05. The half-split method was used to cross-validate the final regression model. Results: Height, mass, and more than 50% of the measured segment lengths and circumferences differed between sexes (η² = 0.053–0.422, p < 0.05). Jump distance correlated with sex, mass, height, arm span, shank and leg length, and upper arm and chest circumference (r = 0.264–0.686, p < 0.05). The final regression model identified sex and chest circumference as predictors of jump distance (adjusted R² = 0.519, p < 0.001). Conclusions: This study enhances the understanding of key anthropometric features influencing long jump performance at an elite level. Recognizing the importance of these characteristics has practical implications for talent identification, athlete assessment, and strength program development.

The influence of lightweight wearable resistance on whole body coordination during sprint acceleration among Australian Rules football players

Article

Full-text available

Nov 2024
PLOS ONE

Rapid acceleration is an important quality for field-based sport athletes. Technical factors contribute to acceleration and these can be deliberately influenced by coaches through implementation of constraints, which afford particular coordinative states or induce variability generally. Lightweight wearable resistance is an emerging training tool, which can act as a constraint on acceleration. At present, however, the effects on whole body coordination resulting from wearable resistance application are unknown. To better understand these effects, five male Australian Rules football athletes performed a series of 20 m sprints with either relatively light or heavy wearable resistance applied to the anterior or posterior aspects of the thighs or shanks. Whole body coordination during early acceleration was examined across eight wearable resistance conditions and compared with baseline (unresisted) acceleration coordination using group- and individual-level hierarchical cluster analysis. Self-organising maps and a joint-level distance matrix were used to further investigate specific kinematic changes in conditions where coordination differed most from baseline. Across the group, relatively heavy wearable resistance applied to the thighs resulted in the greatest difference to whole body coordination compared with baseline acceleration. On average, heavy posterior thigh wearable resistance led to altered pelvic position and greater hip extension, while heavy anterior thigh wearable resistance led to accentuated movement at the shoulders in the transverse and sagittal planes. These findings offer a useful starting point for coaches seeking to use wearable resistance to promote adoption of greater hip extension or upper body contribution during acceleration. Importantly, individuals varied in how they responded to heavy thigh wearable resistance, which coaches should be mindful of.

Sensorimotor Processing in Elite and Sub-Elite Adolescent Sprinters during Sprint Starts: An Electrophysiological Study

Article

Full-text available

Aug 2024

Most studies on sprint performance have focused on kinematics and kinetics of the musculoskeletal system for adults, with little research on the central sensorimotor transmission and processes, especially for adolescent sprinters. This study aimed to determine whether differences in the integrity of the central auditory system and audiomotor transmissions between the elite and sub-elite adolescent sprinters may affect their performance in the 100 m time. Twenty-nine adolescent junior high school students, including elite national-class and sub-elite regional-class athletes, were assessed. Visual and auditory evoked potentials (VEP and AEP) as well as electroencephalography (EEG) and electromyography (EMG) were recorded and analyzed during a sprint start. The electrophysiological results clearly reveal differences in central auditory transmission between elite and sub-elite groups, and between sexes. There were significant differences between elite and sub-elite groups, and during a sprint start, the EEG activities for elite female and male athletes showed significant time-dependent differences in peak amplitudes following the three auditory cues (ready, set, and gunshot). These findings can provide coaches with a more comprehensive consideration for sports-specific selection based on the athletes’ individual conditions, e.g., sensorimotor neuroplastic training for providing precise and efficient training methods to improve young sprinters’ performance.

Acute physiological and psychological responses during an incremental treadmill test wearing a new upper-body sports garment with elastomeric technology

Article

Full-text available

Apr 2024

Background: The use of elastomeric technology in sports garments is increasing in popularity; however, its specific impact on physiological and psychological variables is not fully understood. Thus, we aimed to analyze the physiological (muscle activation of the pectoralis major, triceps brachii, anterior deltoid, and rectus abdominis, capillary blood lactate, systolic and diastolic blood pressure, and heart rate) and psychological (global and respiratory rating of perceived exertion [RPE]) responses during an incremental treadmill test wearing a new sports garment for the upper body that incorporates elastomeric technology or a placebo garment. Methods: Eighteen physically active young adults participated in two randomized sessions, one wearing the elastomeric garment and the other wearing a placebo. Participants performed in both sessions the same treadmill incremental test (i.e., starting at 8 km/h, an increase of 2 km/h each stage, stage duration of 3 min, and inclination of 1%; the test ended after completing the 18 km/h Stage or participant volitional exhaustion). The dependent variables were assessed before, during, and/or after the test. Nonparametric tests evaluated differences. Results: The elastomeric garment led to a greater muscle activation (p < 0.05) in the pectoralis major at 16 km/h (+33.35%, p = 0.01, d = 0.47) and 18 km/h (+32.09%, p = 0.02, d = 0.55) and in the triceps brachii at 10 km/h (+20.28%, p = 0.01, d = 0.41) and 12 km/h (+34.95%, p = 0.04, d = 0.28). Additionally, lower lactate was observed at the end of the test (−7.81%, p = 0.01, d = 0.68) and after 5 min of recovery (−13.71%, p < 0.001, d = 1.00) with the elastomeric garment. Nonsignificant differences between the garments were encountered in the time to exhaustion, cardiovascular responses, or ratings of perceived exertion. Conclusion: These findings suggest that elastomeric garments enhance physiological responses (muscle activation and blood lactate) during an incremental treadmill test without impairing physical performance or effort perception.

Maximal strength, sprint and jump performance in elite kumite karatekas

Article

Full-text available

Jan 2025

Background Both maximal muscle strength and muscle power are independently important for karatekas. However, the relationship between strength and power in elite male kumite karatekas is under researched. This study aimed to determine the relationship between back-leg-chest (BLC) isometric muscle strength with sprint and jump variables in elite male karatekas. Methods Male elite/international level (tier 4) kumite karatekas (n = 14; age, 20.79 ± 1.67 year; height, 1.77 ± 0.06 m; weight, 72.21 ± 5.20 kg) were recruited. BLC strength, sprint and jump values were measured with a dynamometer, a photocell, and an application, respectively. Pearson correlation (trivial r < 0.1; small r < 0.3; moderate r < 0.5; large r < 0.7; very large r < 0.9; nearly perfect/perfect r ≥ 0.9) and linear regression analyses were performed to determine the relationship and shared variance between BLC strength, sprint, and jump performance. Results There were large to very large correlations between BLC strength and sprint time (r = − 0.930, p < 0.01), velocity (r = 0.918; p < 0.01), acceleration (r = 0.913; p < 0.01) and running momentum (r = 0.721; p < 0.01). Additionally, BLC strength correlated with jump height (moderate, r = 0.550, p < 0.05), peak anaerobic power (moderate, r = 0.672, p < 0.01) and power to body mass ratio (moderate, r = 0.545, p < 0.05). BLC strength and sprint variables showed an r² = 0.52–0.86 (p < 0.01), while BLC strength and jump variables showed an r² = 0.29–0.45 (p < 0.05). Conclusions BLC strength is related to jump and sprint performance in male elite karate athletes. This relationship underscores the importance of including strength training that targets BLC muscle strength in training programs for coaches and athletes.

Impact of elbow stiffness on running economy in trained athletes

Article

Dec 2024

Background Elbow injuries are likely to generate a decreased range of motion (ROM), which might negatively affect athletic performance. To date, the effect of elbow stiffness on endurance running performance has never been studied. We conducted an observational, prospective, cross-over study to examine the impact of elbow stiffness on running economy. Methods Twenty trained athletes performed running economy tests at 12 km·h ⁻¹ , with and without a limited elbow ROM (flexion: 90°, extension: 45°), imposed by a dynamic brace mimicking a severe elbow stiffness. Relative intensity and performance indexes were measured during a subsequent maximal incremental exercise test. Results Running economy was measured at 180 ± 10.6 mlO 2 ·km ⁻¹ ·kg ⁻¹ with a full ROM, and 180.2 ± 12.3 mlO 2 ·km ⁻¹ ·kg ⁻¹ with the limited ROM showing a non-significant 0.1% difference ( p = 0.871). Discussion Athletes experiencing post-traumatic elbow stiffness can find reassurance in knowing that it does not seem to impact a crucial metric of endurance running performance, namely running economy. Further research could explore elbow movement at different intensities of running, from higher aerobic speeds to sprinting.

Influencia del Braceo en la Carrera y su Implicancia en el Deporte Paralímpico. Una Revisión Narrativa

Article

Full-text available

Dec 2024

Introducción. El deporte paralímpico tiene como objetivo proporcionar oportunidades competitivas y recreativas a personas con diversas discapacidades, incluidas aquellas con limitación de la movilidad o amputación de miembros superiores. Se ha descrito que los miembros superiores tienen un efecto importante en la carrera, por ejemplo, minimizando los momentos rotatorios producidos por los miembros inferiores durante esta acción. Sin embargo, existe escasa información respecto a los efectos en la carrera de la limitación de la movilidad o amputación de miembros superiores en atletas paralímpicos. Objetivo. Describir la influencia del braceo tanto en carreras de velocidad como en el deporte paralímpico. El braceo se define como un movimiento rítmico, alternado y sincronizado de los brazos, en sentido antero-posterior en oposición al movimiento de miembros inferiores. Este movimiento se ha descrito como esencial para contrarrestar el torque generado por las zancadas, facilitando un desplazamiento más eficiente y equilibrado. En las carreras de velocidad paralímpicas, los atletas pueden tener distintos tipos de amputación de miembros superiores, lo cual influye significativamente en la ejecución del braceo en comparación con las carreras convencionales. Las prótesis de miembros superiores, diseñadas para proporcionar una funcionalidad que permita realizar actividades diarias y deportivas, varían desde dispositivos puramente estéticos hasta avanzadas prótesis mioeléctricas. Una prótesis cómoda y ligera, adaptada a las necesidades del deportista, permite un mayor rango articular y asegura una altura simétrica en la posición inicial de los tacos, mejorando así el inicio de la carrera. Conclusiones. A pesar de la relevancia de estos aspectos, es notable que la investigación científica en este campo aún presenta vacíos significativos. Una mayor exploración y análisis de cómo el braceo afecta específicamente el rendimiento y la salud de los deportistas paralímpicos no solo enriquecerá nuestro entendimiento teórico, sino que también informará estrategias más efectivas de entrenamiento y rehabilitación.

Acute Kinematic and Kinetic Adaptations to Wearable Resistance During Sprint Acceleration

Article

Full-text available

Aug 2016

Wearable resistance (WR) in the form of weighted vests and shorts enables movement specific sprint running to be performed under load. The purpose of this study was to determine the acute changes in kinematics and kinetics when an additional load equivalent to 3% body mass (BM) was attached to the anterior or posterior surface of the lower limbs during sprint running. Nineteen male rugby athletes (age: 19.7 ± 2.3 years; body mass: 96.1 ± 16.5 kg; height: 181 ± 6.5 cm) volunteered to participate in the study. Subjects performed six 20 m sprints in a randomized fashion wearing no resistance or 3%BM affixed to the anterior (quadriceps and tibialis anterior) or posterior (hamstring and gastrocnemius) surface of the lower limbs (two sprints per condition). Optojump and radar were used to quantify sprint times, horizontal velocity, contact and flight times, and step length and frequency. A repeated measures analysis of variance with post hoc contrasts was used to determine differences (p ≤ 0.05) between conditions. No significant differences were found between the anterior and posterior WR conditions in any of the variables of interest. There was no significant change in sprint times over the initial 10 m, however the 10 to 20 m split times were significantly slower (-2.2 to -2.9%) for the WR conditions compared to the unloaded sprints. A significant change in the relative force-velocity (F-v) slope (-10.5 to -10.9%) and theoretical maximum velocity (V0) (-5.4 to -6.5%) was found, while a non-significant increase in theoretical maximum force (F0) (4.9 to 5.2%) occurred. WR of 3%BM may be a suitable training modality to enhance sprint acceleration performance by overloading the athlete without negatively affecting sprint running technique.

Case Studies of Asymmetrical Arm Action in Running

Article

Full-text available

May 1992

Richard Hinrichs

Ten male recreational runners ranging in age from 20 to 32 years were filmed using 3-D cinematography while running on a treadmill at 3.8 m/s, 4.5 m/ s, and 5.4 m/s. The 3-D segment endpoint data were entered into a computer program that computed the segmental contributions to the upward and forward propulsive impulses on the body (lift and drive, respectively) and to the vertical component of angular momentum (Hz). The results of two subjects who demonstrated asymmetrical arm action are discussed in detail and compared with the mean results computed over all subjects. The results revealed that the arms possess the potential to compensate for each other and for asymmetries elsewhere in the body.

Mechanics of Standing and Crouching Sprint Starts

Article

Full-text available

Jun 2016

The aim of this study was to compare the kinetic and kinematic parameters of standing and crouch sprint starts. Parallel starts (PS), false starts (FS), jump starts (JS) and crouch starts (3PS) were compared. Eighteen participants performed each start on a force plate and six infrared cameras captured the three-dimensional coordinates of 36 retro-reflective markers. Performance during a five-metre sprint (T5m) was analysed. Duration of the start phase (Tstart), mean values of horizontal and total ground reaction forces (GRFs) (Fx_mean and Ftot_mean), ratio of force (RF), maximal power (Pmax) and kinetic energy (KE) of each limb were calculated. Significant differences were found for T5m, Tstart, KE, Pmax, Fx_mean, Ftot_mean and RF for the crouch start compared to the other starts (P ≤ 0.05). Significant correlations were found between T5m and Tstart (r = 0.59; P ≤ 0.001), and T5m and Pmax, Fx_mean and RF (−0.73 ≤ r ≤ −0.61; P ≤ 0.001). To conclude, the crouch start resulted in the best performance because Tstart was shorter, producing greater Pmax, Fx_mean with a more forward orientation of the resultant force. Greater KE of the trunk in each start condition demonstrated the role of the trunk in generating forward translation of the centre of mass (CM).

Scapula behavior associates with fast sprinting in first accelerated running

Article

Full-text available

May 2016

The arm-swing motion is important for coordinated lower limb movement during a fast sprint and is composed of three-dimensional scapulothoracic and glenohumeral joint motion. Here, we aimed to clarify the role of the scapula during the initiation of a sprint running when sprinter run with high horizontal acceleration. Ten sports-active students participated in four 5-m dashes, with scapular constraint using non-elastic therapy tape (constraint condition) and without scapular constraint (free condition). The sprinting kinematics was assessed by a 16-camera motion capture system. In the constraint condition, the 2-m sprint time was significantly longer than that in the free condition. At the instants of foot-contact and take-off during the first step, no significant difference in the humerothoracic flexion angle was seen between these two conditions. In contrast, at the instants of foot-contact and take-off during the first step, the humerothoracic extension angle in the constraint condition was significantly smaller than that in the free condition. The forward leaning vector angle of center of mass during the first step was significantly greater than that in the constraint condition. Although no significant difference in hip extension and foot forward leaning angles was seen at the instant of foot contact during the first step between the two conditions, at the instant of take-off, the hip extension and foot forward leaning angles in the constraint condition were significantly smaller than those in the free condition. Therefore, scapular behavior in first accelerated running contributes to larger upper- and lower-limb motions and facilitates coordinating whole-body balance for a fast sprint.

An insight into track and field coaches’ knowledge and use of sprinting drills to improve performance

Article

Full-text available

Apr 2016

Coaches’ knowledge of drills and their specificity to sprint movement patterns and muscle activations have become increasingly important. Drills are used to encourage the development of optimal movement and coordination. They are prescribed to help the athlete develop sprint technique, and it is generally assumed that the drills are the parts within a whole-part-whole learning strategy. Previous literature has suggested some drills may be questionable as they may not replicate the muscle activations or movement pattern of sprinting. A total of 209 coaches completed an online questionnaire, which examined coaches’ choice of drills; reasons for using each drill and reasons for changing drills used. The results were analysed using qualitative and quantitative methods. Results showed that coaches believed that drills are a vital part of training to improve performance but that they should be specific to sprinting technique.

Efficient arms for efficient agility

Article

Full-text available

Aug 2003

Upper Extremity Function in Running. II: Angular Momentum Considerations

Article

Full-text available

Aug 1987

Richard Hinrichs

Ten male recreational runners were filmed using three-dimensional cinematography while running on a treadmill at 3.8 m/s, 4.5 m/s, and 5.4 m/s. A 14-segment mathematical model was used to examine the contributions of the arms to the total-body angular momentum about three orthogonal axes passing through the body center of mass. The results showed that while the body possessed varying amounts of angular momentum about all three coordinate axes, the arms made a meaningful contribution to only the vertical component (Hz). The arms were found to generate an alternating positive and negative Hz pattern during the running cycle. This tended to cancel out an opposite Hz pattern of the legs. The trunk was found to be an active participant in this balance of angular momentum, the upper trunk rotating back and forth with the arms and, to a lesser extent, the lower trunk with the legs. The result was a relatively small total-body Hz throughout the running cycle. The inverse relationship between upper- and lower-body angular momentum suggests that the arms and upper trunk provide the majority of the angular impulse about the z axis needed to put the legs through their alternating strides in running.

Upper Extremity Function in Running. I: Center of Mass and Propulsion Considerations

Article

Full-text available

Aug 1987

Ten male recreational runners were filmed using three-dimensional cinematography while running on a treadmill at 3.8 m/s, 4.5 m/s, and 5.4 m/s. A 14-segment mathematical model was used to examine the influence of the arm swing on the three-dimensional motion of the body center of mass (CM), and on the vertical and horizontal propulsive impulses (“lift” and “drive”) on the body over the contact phase of the running cycle. The arms were found to reduce the horizontal excursions of the body CM both front to back and side to side, thus tending to make a runner's horizontal velocity more constant. The vertical range of motion of the body CM was increased by the action of the arms. The arms were found to make a small but important contribution to lift, roughly 5–10% of the total. This contribution increased with running speed. The arms were generally not found to contribute to drive, although considerable variation existed between subjects. Consistent with the CM results, the arms were found to reduce the changes in forward velocity of the runner rather than increasing them. It was concluded that there is no apparent advantage of the “classic” style of swinging the arms directly forward and backward over the style that most distance runners adopt of letting the arms cross over slightly in front. The crossover, in fact, helps reduce side-to-side excursions of the body CM mentioned above, hence promoting a more constant horizontal velocity.

Increases in Lower-Body Strength Transfer Positively to Sprint Performance: A Systematic Review with Meta-Analysis

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Full-text available

Jul 2014

Background: Although lower-body strength is correlated with sprint performance, whether increases in lower-body strength transfer positively to sprint performance remain unclear. Objectives: This meta-analysis determined whether increases in lower-body strength (measured with the free-weight back squat exercise) transfer positively to sprint performance, and identified the effects of various subject characteristics and resistance-training variables on the magnitude of sprint improvement. Methods: A computerized search was conducted in ADONIS, ERIC, SPORTDiscus, EBSCOhost, Google Scholar, MEDLINE and PubMed databases, and references of original studies and reviews were searched for further relevant studies. The analysis comprised 510 subjects and 85 effect sizes (ESs), nested with 26 experimental and 11 control groups and 15 studies. Results: There is a transfer between increases in lower-body strength and sprint performance as indicated by a very large significant correlation (r = -0.77; p = 0.0001) between squat strength ES and sprint ES. Additionally, the magnitude of sprint improvement is affected by the level of practice (p = 0.03) and body mass (r = 0.35; p = 0.011) of the subject, the frequency of resistance-training sessions per week (r = 0.50; p = 0.001) and the rest interval between sets of resistance-training exercises (r = -0.47; p ≤ 0.001). Conversely, the magnitude of sprint improvement is not affected by the athlete's age (p = 0.86) and height (p = 0.08), the resistance-training methods used through the training intervention, (p = 0.06), average load intensity [% of 1 repetition maximum (RM)] used during the resistance-training sessions (p = 0.34), training program duration (p = 0.16), number of exercises per session (p = 0.16), number of sets per exercise (p = 0.06) and number of repetitions per set (p = 0.48). Conclusions: Increases in lower-body strength transfer positively to sprint performance. The magnitude of sprint improvement is affected by numerous subject characteristics and resistance-training variables, but the large difference in number of ESs available should be taken into consideration. Overall, the reported improvement in sprint performance (sprint ES = -0.87, mean sprint improvement = 3.11 %) resulting from resistance training is of practical relevance for coaches and athletes in sport activities requiring high levels of speed.

Kinematic Analysis of Olympic Sprint Performance: Men's 200 Meters

Article

May 1985

Selected kinematic variables in the performance of the Gold and Silver medalists and the eighth-place finisher in the men's 200-meter sprint final at the 1984 Summer Olympic Games were investigated. Cinematographic records were obtained for all track running events at the Games, with the 200-meter performers singled out for initial analysis. In this race, sagittal view filming records (100 fps) were collected at the middle (125-meter mark) and end (180-meter mark) of the performance. Computer-generated analysis variables included both direct performance variables (body velocity, stride rate, etc.) and upper and lower body kinematics (upper arm position, lower leg velocity, etc.) that have previously been utilized in the analysis of elite athlete sprinters. The difference in place finish was related to the performance variables body horizontal velocity (direct), stride rate (direct), and support time (indirect). The critical body kinematics variables related to success included upper leg angle at takeoff (indirect), upper leg velocity during support (direct), lower leg velocity at touchdown (direct), foot to body touchdown distance (indirect), and relative foot velocity at touchdown.