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This study aimed to analyse the influence of muscular performance parameters on spatio-temporal gait characteristics during running when gradually increasing speed. 51 recreationally trained male endurance runners (age: 28 ± 8 years) voluntarily participated in this study. Subjects performed a battery of jumping tests (squat jump, countermovement jump, and 20 cm drop jump), and after that, the subjects performed an incremental running test (10 to 20 km/h) on a motorized treadmill. Spatio-temporal parameters were measured using the OptoGait system. Cluster k-means analysis grouped subjects according to the jumping test performance, by obtaining a group of good jumpers (GJ, n = 19) and a group of bad jumpers (BJ, n = 32). With increased running velocity, contact time was shorter, flight time and step length longer, whereas cadence and stride angle were greater (p < 0.001). No significant differences between groups (p ≥ 0.05) were found at any running speed. The results obtained indicate that increased running velocity produced no differences in spatio-temporal adaptations between those runners with good jumping ability and those with poor jumping ability. Based on that, it seems that muscular performance parameters do not play a key role in spatio-temporal adaptations experienced by recreational endurance runners with increased velocity. However, taken into consideration the well-known relationship between running performance and neuromuscular performance, the authors suggest that muscular performance parameters would be much more determinant in the presence of fatigue (exhausted condition), or in the case of considering other variables such as running economy or kinetic.
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LACK OF INFLUENCE OF MUSCULAR PERFORMANCE
PARAMETERS ON SPATIOTEMPORAL ADAPTATIONS
WITH INCREASED RUNNING VELOCITY
LUIS E. ROCHE-SERUENDO,
1
FELIPE GARCI
´A-PINILLOS,
2
JOANA HAICAGUERRE,
1
ANA V. BATALLER-
CERVERO,
1
VI
´CTOR M. SOTO-HERMOSO,
3
AND PEDRO A
´.LATORRE-ROMA
´N
2
1
San Jorge University, Zaragoza, Spain;
2
Department of Corporal Expression, University of Jaen, Jaen, Spain; and
3
Department of Sport Sciences, University of Granada, Granada, Spain
ABSTRACT
Roche-Seruendo, LE, Garcı
´a-Pinillos,F,Haicaguerre,J,Bataller-
Cervero, AV, Soto-Hermoso, VM, and Latorre-Roma
´n, PA
´.Lack
of influence of muscular performance parameters on spatiotem-
poral adaptations with increased running velocity. J Strength
Cond Res 32(2): 409–415, 2018—This study aimed to analyze
the influence of muscular performance parameters on spatiotem-
poral gait characteristics during running when gradually increas-
ing speed. Fifty-one recreationally trained male endurance
runners (age, 28 68 years) voluntarily participated in this study.
Subjects performed a battery of jumping tests (squat jump, coun-
termovement jump, and 20-cm drop jump), and after that, the
subjects performed an incremental running test (10–20 km$h
21
)
on a motorized treadmill. Spatiotemporal parameters were mea-
sured using the OptoGait system. Cluster k-means analysis
grouped subjects according to the jumping test performance,
by obtaining a group of good jumpers (n= 19) and a group of
bad jumpers (n= 32). With increased running velocity, contact
time was shorter and flight time and step length were longer,
whereas cadence and stride angle were greater (p,0.001).
No significant differences between groups (p$0.05) were
found at any running speed. The results obtained indicate that
increased running velocity produced no differences in spatiotem-
poral adaptations between those runners with good jumping abil-
ity and those with poor jumping ability. Based on that, it seems
that muscular performance parameters do not play a key role in
spatiotemporal adaptations experienced by recreational endur-
ance runners with increased velocity. However, taken into con-
sideration the well-known relationship between running
performance and neuromuscular performance, the authors sug-
gest that muscular performance parameters would be much
more determinant in the presence of fatigue (exhausted condi-
tion) or in the case of considering other variables such as running
economy or kinetic.
KEY WORDS endurance runners, jumping ability, reactive
strength index, running kinematics
INTRODUCTION
Distance running performance is influenced not
only by factors related to oxygen uptake and
utilization but also by factors related to muscle
recruitment and force production (28,29).
Although success in endurance sports requires high maxi-
mal oxygen uptake (V
_
O
2
max), it cannot fully explain all the
measured differences in endurance performance. Simulta-
neous strength and endurance training has been shown to
improve muscle strength, running economy (RE), and dis-
tance running performance without any changes in
V
_
O
2
max (29), suggesting that neuromuscular factors are
also important determinants of endurance running perfor-
mance. In fact, jumping ability has been associated with
short-distance running performance (10,19) and also with
long-distance events (19).
Additionally, the way in which one move (running
biomechanicsinthiscase)canfavororlimithisorher
running performance by influencing RE and efficiency
(1,2,25,34). It is reliant on a complex interaction of factors
that lead to efficient muscular work and result in fast and
effective running gait (2,34). Traditionally, physiological
factors, muscle fiber distribution, age, sex, and anthropo-
metric factors have been found to account for interindivid-
ual variability in RE (2,34). However, RE is also influenced
by biomechanical variables, largely contributed from
ground contact and stride characteristics (31,34)—small
vertical oscillations (1), greater stride angles (31), longer
strides (1), and lower ground reaction forces (17) have been
related to superior RE.
Both neuromuscular and biomechanical parameters
during running are highly influenced by running velocity
(5,18). Increases in running speed lead to greater levels of
neuromuscular engagement (mainly in the hamstring
Address correspondence to Felipe Garcı
´a-Pinillos, fegarpi@gmail.com.
32(2)/409–415
Journal of Strength and Conditioning Research
Ó2017 National Strength and Conditioning Association
VOLUME 32 | NUMBER 2 | FEBRUARY 2018 | 409
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
muscles) (18). Likewise, it seems clear that to run faster,
ground contact time (CT) need to be decreased to aid in
repositioning the legs during running (5), whereas step
length (SL) is suggested to increase linearly with running
velocity up to 25 km$h
21
(5). Additionally, increased run-
ning velocity led to a greater hip flexion and lower ankle
flexion at the initial contact, lower knee and ankle flexions
at midstance, and greater hip extension at toe-off (5–7,9).
These differences appear to be totally logical because
lower ankle flexion at the initial contact and lower knee
and ankle flexions at midstance have been associated to
shorter CT (5,9).
However, the question is, are those spatiotemporal
adaptations dependent on muscular performance parame-
ters? As far as the authors know, no previous studies have
investigated whether kinematic alterations (spatiotemporal
adaptations specifically) to increased running velocity differ
between those runners with a good jumping ability and
those without (an indirect way to measure neuromuscular
performance (3)). Therefore, the main goal of this study was
to analyze the influence of muscular performance parame-
ters on spatiotemporal gait characteristics during running
when gradually increasing speed. The authors hypothesize
that runners with good muscular performance will experi-
ence different spatiotemporal adaptations in response to an
increase in running velocity than those with a lower muscu-
lar performance.
METHODS
Experimental Approach to the Problem
Endurance runners performed an incremental running test
and a battery of jumping tests. An analysis of the dynamic of
spatiotemporal gait characteristics at different velocities
during running on a treadmill was performed, as well as to
determine its relationship with the muscular performance
parameters (measured in a laboratory setting). A unilateral
crossover design was used, with all subjects performing the
same protocol and conditions.
Subjects
A group of 51, recreationally trained, male, endurance
runners (6SD age, 28 68 years; age range, 18–40 years;
height, 178 67 cm; body mass, 73 68 kg) voluntarily
participated in this study. All subjects met the inclusion
criteria: (a) older than 18 years; (b) recreationally active
(3–4 running sessions per week, at least once on a tread-
mill); (c) able to run 5-km in less than 25 minutes; and (d)
had not suffered from any injury within the past 6 months
before the data collection. After receiving detailed infor-
mation on the objectives and procedures of the study,
each subject signed an informed consent form to partici-
pate, which complied with the ethical standards of the
World Medical Association’s Declaration of Helsinki
(2013); it was made clear that the subjects were free to
leave the study if they saw fit. The study was approved by
the Ethics Committee of the San Jorge University (Zara-
goza, Spain).
Procedures
The study was conducted in February 2016. At the time of
these observations, the subjects had completed between 2
and 4 months of training. Subjects were cited on 1 specific
day, and they were individually tested (between 16:00 and
21:00 hours). Before all testing, subjects refrained from
severe physical activity for at least 48 hours, and all testing
was at least 3 hours after ingestion of a meal. Tests were
performed with the subjects wearing their usual training
shoes to attain their most typical performance.
Before the running protocol, the subjects performed
a warm-up, which consisted of 10 minutes of continuous
running and 5 minutes of general exercises (high skipping,
leg flexion, jumping exercises, and short bursts of accelera-
tion). Then, the subjects performed a battery of jumping tests
(squat jump [SJ], countermovement jump [CMJ], and 20-cm
drop jump [DJ20]), and after that, the subjects performed an
incremental running test on a motorized treadmill (Salter M-
835; Salter, Int., Barcelona, Spain).
The treadmill protocol was preceded by a standardized
10-minute accommodation program. The subjects were
experienced in running on a treadmill, but anyway, previous
studies (32) on human locomotion have shown that accom-
modation to a new condition occurs in approximately 8 mi-
nutes. The running test started at 10 km$h
21
, and running
speed was increased 1 km$h
21
every 20 seconds (10-second
acclimatization period: 10-second recording period), finish-
ing at 20 km$h
21
for all subjects. The short duration of speed
conditions aimed to minimize the effect of fatigue on run-
ning kinematics and let most of the subjects complete this
speed range (10–20 km$h
21
) at which recreational runners
usually run in both training and competition.
Materials and Testing
Anthropometry. For descriptive purposes, height (cm) and
body mass (kg) were determined using a precision stadiom-
eter and balance (SECA 222 and 634, respectively; SECA,
Corp., Hamburg, Germany). All measurements were taken
with the subjects wearing running shorts and underwear.
Biomechanics. Spatiotemporal parameters were measured
using the OptoGait system (Microgate, Bolzano, Italy),
which was previously validated for the assessment of
spatiotemporal parameters of the gait of young adults,
reporting a high level of correlation with all spatiotemporal
parameters by intraclass correlation coefficients (ICCs)
(0.785–0.952), coefficients of variation (1.66–4.06%), stan-
dard error of measurement (2.17–5.96%), and minimum
detectable change (6.01–16.52%) (20). The 2 parallel bars
of the device system were placed on the side edges of the
treadmill at the same level as the contact surface. This device
was connected to a computer controlled by the researcher.
Data were recorded and averaged for the subsequent
Muscle Performance and Spatiotemporal Parameters
410
Journal of Strength and Conditioning Research
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TM
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
analysis. In accordance with the findings from Brown et al.
(4), limb dominance was not taken into account. Stride
angle, CT, flight time (FT), SL, and stride frequency (SF)
were measured for every step during the treadmill test.
CT (seconds): time from when the foot contacts the
ground to when the toes lift off the ground.
FT (seconds): time from toe-off to initial ground con-
tact of consecutive footfalls of the same foot.
SL (meters): length the treadmill belt moves from toe-
off to initial ground contact in successive steps.
SF (steps$min
21
): number of ground contact events
per minute.
Stride angle (8): angle of the parable tangent derived
from the theoretical arc traced during a stride between
the foot and the ground (31). The theoretical parabola
for the stride angle determination was calculated by the
system through the stride length and the maximal
height of the foot during a stride. The determination
of stride length is described above, and the maximal
height of the foot during a stride was calculated by
the OptoGait system as indicated by Santos-
Concejero et al. (31).
Muscular performance. It is indirectly measured through
jumping test. The CMJ, SJ, and DJ20 (from a 20-cm height
box) were recorded using the same system (OptoGait;
Microgate), a technology previously validated (14). This
device measures the CT on the floor and the FT, using
photoelectric cells. Flight time was used to calculate the
height of the rise using the body’s center of gravity. Subjects
performed 2 trials of every test, with a 15-second recovery
period between them with the best trial being used for the
statistical analysis. Subjects were encouraged to achieve
maximum performance throughout both running and jump-
ing protocols.
Vertical jumping tests are commonly used to evaluate
muscular performance (12,13) and the effectiveness of the
stretch-shortening cycle in runners (10,15). Additionally, the
ability to develop force quickly is a requisite ability in most
sports and the reactive strength index (RSI) has been developed
as a measure of explosive strength and is derived by evaluating
jump height divided by ground CT during the DJ (11). Reactive
strength index was also calculated in the current study.
Statistical Analyses
Descriptive statistics are represented as mean (SD). Tests of
normal distribution and homogeneity (Kolmogorov and
Levene’s test, respectively) were conducted on all data
before analysis. A cluster k-means was performed by group-
ing according to the jumping tests performance (CMJ, SJ,
and DJ20). A 1-way analysis of variance (ANOVA) was per-
formed to compare subgroups (anthropometric characteris-
tic, spatiotemporal, and muscular performance parameters).
A repeated measures ANOVA was performed to determine
the effect of velocity on spatiotemporal parameters for the
whole group and the subgroups created. The reliability of
TABLE 1. Characteristic of participants (mean, SD).*
Variables Males (n= 51) Good jumpers (n= 19) Bad jumpers (n= 32) p
Age (y) 27.56 (7.54) 26.50 (5.02) 28.19 (8.7) 0.442
Height (m) 1.78 (0.07) 1.79 (0.05) 1.77 (0.08) 0.544
Body mass (kg) 73.12 (7.96) 73.68 (6.68) 72.77 (8.74) 0.699
BMI 22.09 (1.82) 23.10 (1.69) 23.09 (1.92) 0.977
*BMI = body mass index.
TABLE 2. Jumping test performance (mean, SD).*
Variables Males (n= 51) Good jumpers (n= 19) Bad jumpers (n= 32) p
CMJ (cm) 33.46 (5.56) 38.86 (3.84) 30.26 (3.59) ,0.001
DJ20 (cm) 29.02 (4.76) 32.61 (4.85) 26.88 (3.19) ,0.001
SJ (cm) 27.45 (5.59) 32.69 (4.43) 24.35 (3.49) ,0.001
RSI 122.41 (30.62) 141.78 (25.24) 110.89 (27.83) ,0.001
*CMJ = countermovement jump; DJ20 cm = drop jump from a 20-cm height; SJ = squat jump; RSI = reactive strength index (height
reached during DJ20/contact time).
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jumping ability test (CMJ, DJ20, and SJ) was assessed using
ICCs between test-retest and confidence interval (CI).
RESULTS
Test-retest reliability analysis of jumping tests performed in
this study shows an ICC of 0.986 (95% CI, 0.972–0.993) for
the CMJ, ICC of 0.963 (95% CI, 0.927–0.981) for the SJ, and
ICC of 0.883 (95% CI, 0.637–0.963) for the DJ20.
Table 1 shows the anthropometric characteristic of sub-
jects for the whole group and for the subgroups created
according to the vertical jump performance. No between-
group differences (p$0.05) were found in any variable
(age, height, body mass, body mass index).
Cluster k-means analysis grouped subjects according to
the jumping tests performance, by obtaining a group of good
jumpers (GJ, n= 19) and a group of bad jumpers (BJ, n= 32).
Between-group differences (Table 2) were found in CMJ
(+8.6 cm; p,0.001), DJ20 (+5.93 cm; p,0.001), SJ
(+8.34 cm; p,0.001), and RSI (30.89; p,0.001).
The effect of velocity on temporal gait parameters is
shown in Figure 1. With increased running velocity, CT was
shorter and FT was longer (significant changes in every +1
Figure 1. Temporal parameters (contact time and flight time) with increased running velocity for the whole group and groups created according to jumping
ability.
Figure 2. Spatiotemporal parameters with increased running velocity for the whole group and groups created according to jumping ability.
Muscle Performance and Spatiotemporal Parameters
412
Journal of Strength and Conditioning Research
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km$h
21
step; p,0.001) with no significant differences
between groups at any running speed (p$0.05).
The effect of running velocity on spatiotemporal variables
(SL, SF, and stride angle) is presented in Figure 2. With
increased running velocity, SL was longer and SF and stride
angle were greater (p,0.001), with no significant differ-
ences between groups at any running speed (p$0.05).
DISCUSSION
This study aimed to analyze the influence of muscular
performance parameters on spatiotemporal adaptations
during running at different velocities (incremental, from
10 to 20 km$h
21
).Themainfindingofthecurrentstudy
was the lack of between-group differences (GJ vs. BJ) in
the kinematic adaptations experienced by subjects when
they increased running velocity. With increased running
velocity, even though in a nonfatigued condition, CT was
shorter, FT and SL were longer, and SF and stride angle
were greater, but no differences were found between
groups of GJ and BJ—an indirect measure of muscular
performance (3).
Regarding spatiotemporal adaptations with increased run-
ning velocity, the results obtained in the current study
reinforce the findings of previous studies. It seems clear that
to run faster, FT needs to be increased and CT needs to be
decreased to aid in repositioning the legs during running (5).
Based on that relationship, SF also needs to be increased to
run faster (26). More controversial is the dynamic of SL when
velocity increases. It has been suggested that SL increases
linearly with running velocity up to 25 km$h
21
(5), which is
in consonance with our findings (SL increased over the pro-
tocol up to 20 km$h
21
). Changes in these parameters during
running have been suggested as the influencing factors
on impact shock (16,23,24) and, thereby, on the risk of
injury (21–23). Changes in spatiotemporal parameters at a fixed
speed can alter electromyography and kinetics (8,16,21,22,33)
and, thereby, the magnitude and rate of impact force loading
during the stance phase of running (23). Running injuries may
be associated with that magnitude and rate of impact force
loading during the stance phase of running (23).
As for the stride angle, the available information is quite
limited, which makes comparisons much more difficult. A
previous study by Santos-Concejero et al. (31) points to
stride angle as an easily obtainable measure that reveals
greater potential for running performance and RE than
other biomechanical variables. The current study shows
that stride angle increases with an increased running veloc-
ity, and this finding is in consonance with the results re-
ported by that study (31). The authors suggest that this
adaptation may be a marker of the ability of the athlete
to efficiently maximize FT and minimize CT with effective
energy transfer during ground contact. Greater stride an-
gles would lead athletes to experience shorter CT, allowing
a better RE (27,31). As indicated by previous studies (31),
this phenomenon could be the result of an early contrac-
tion of the muscles involved in the movement of a stride
during the stance phase, leading the center of mass to be
projected forward more efficiently. All these changes in
spatiotemporal parameters have also been associated to
athletic performance. For example, when SF is manipulated
during running, the musculoskeletal system alters the
mechanical behavior of its spring system (26), and this
yields an effect on parameters related to RE and efficiency
(34). Increased SF results in decreased ground CT, vertical
displacement of center of mass, and leg length variation
(compression) (26,34). Likewise, CT appears to be a strong
and direct determinant of leg stiffness (26)—decreasing CT
yielded an increase in leg stiffness and vice versa (26).
On the other hand, the results obtained in the current
study indicated that there were no differences in the
aforementioned spatiotemporal adaptations with increased
running velocity between groups with GJ and BJ, respec-
tively (an indirect measure of muscular performance (3)).
Although the effect of running velocity on spatial and tem-
poral parameters seems clear, the involvement of neuro-
muscular factors on these adaptations has not yet been
determined. It seems well established that neuromuscular
factors are important determinants of endurance running
performance (10,19,28,29). As indicated by Pruyn et al.
(30), higher levels of lower-body stiffness seem to be
advantageous for athletes when performing rapid and
(or) repeated stretch-shorten cycle movements (i.e., run-
ning). Both muscle and tendon properties may be impor-
tant in this transfer of energy during human locomotion.
Stored energy in these springs (muscle and tendon) could
conceivably reduce muscle activation and spare energy
expenditure, thus improving RE (10), and that is why the
authors hypothesized that runners would experience dif-
ferent spatiotemporal adaptations according to their mus-
cular performance. Nevertheless, this study indicates that
spatiotemporal adaptations to an incremental running pro-
tocol are not determined by muscular parameters, at least
in these conditions: amateur endurance runners perform-
ing an incremental test in the absence of fatigue. The au-
thors suggest that muscular performance parameters might
be much more determinant in the presence of fatigue (ex-
hausted condition) or in the case of considering other var-
iables, such as RE or running kinetics.
Finally, some limitations must be taken into consider-
ation when interpreting these results. First, sex differences
were not assessed, with female subjects not participating in
the current study. Second, the lack of data related to
parameters that might play an important role in this
relationship, such as ground reaction forces (running
kinetic) and RE measures. Notwithstanding these limita-
tions, the current study highlights the dynamic of spatio-
temporal parameters during an incremental running test in
amateur endurance runners (parameters frequently used by
coaches and clinicians for assessing athletes) and deter-
mines the lack of influence of neuromuscular parameters on
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spatiotemporal adaptations with increased running velocity
(inamateurrunnersandintheabsenceoffatigue).
In conclusion, the results obtained indicate that
increased running velocity produced no differences in
spatiotemporal adaptations between those runners with
good jumping ability and those with badjumping ability.
However, taking into consideration the well-known rela-
tionship between running performance and neuromuscular
performance, the authors suggest that muscular perfor-
mance parameters might be much more determinant in
the presence of fatigue (exhausted condition) or in the case
of considering other variables, such as RE or running
kinetics.
PRACTICAL APPLICATIONS
From a practical point of view, these data suggest that
coaches and sport scientists should be prudent to establish
relationships between running kinematics and neuromus-
cular parameters through an isolated assessment. It seems
that muscular performance parameters do not play a key
role in spatiotemporal adaptations experienced by recrea-
tional endurance runners with increased velocity (at least,
under these conditions: lack of fatigue effects and amateur
runners).
ACKNOWLEDGMENTS
This paper is part of the thesis of the first author L. E. Roche-
Seruendo The thesis plan is registered in the PhD program in
Biomedicine (B11/56/1) of Universidad de Granada (Granada,
Spain). This work was supported by the Spanish Ministry of
Economy and Competitiveness together with the European
Fund for Regional Development, Project “AVISaMe” ref.
DEP2015-70980-R (MINECO/FEDER, EU). The authors
thank all the athletes who participated in the research
and Fisio-Zaragoza for facilitating installation and resour-
ces without any interest. The authors declare no conflict of
interests.
REFERENCES
1. Anderson, T. Biomechanics and running economy. Sport Med 22:
76–89, 1996.
2. Barnes, KR and Kilding, AE. Running economy: Measurement,
norms, and determining factors. Sport Med Open 1: 8, 2015.
3. Bosco, C, Tihanyi, J, Atteri, FL, Fekete, G, Apor, P, and Rusko, H.
The effect of fatigue on store and re-use of elastic energy in slow and
fast types of human skeletal muscle. Acta Physiol Scand 128: 109–117,
1986.
4. Brown, AM, Zifchock, RA, and Hillstrom, HJ. The effects of limb
dominance and fatigue on running biomechanics. Gait Posture 39:
915–919, 2014.
5. Brughelli, M, Cronin, J, and Chaouachi, A. Effects of running
velocity on running kinetics and kinematics. J Strength Cond Res 25:
933–939, 2011.
6. Castro, A, LaRoche, DP, Fraga, CHW, and Gonc¸alves, M.
Relationship between running intensity, muscle activation, and
stride kinematics during an incremental protocol. Sci Sports 28: e85–
e92, 2013.
7. Chan-Roper, M, Hunter, I, W Myrer, J, L Eggett, D, and K Seeley,
M. Kinematic changes during a marathon for fast and slow runners.
J Sports Sci Med 11: 77–82, 2012.
8. Chumanov, ES, Wall-Scheffler, C, and Heiderscheit, BC. Gender
differences in walking and running on level and inclined surfaces.
Clin Biomech (Bristol, Avon) 23: 1260–1268, 2008.
9. Daoud,AI,Geissler,GJ,Wang,F,Saretsky,J,Daoud,YA,and
Lieberman, DE. Foot strike and injury rates in endurance
runners: A retrospective study. Med Sci Sports Exerc 44: 1325–
1334, 2012.
10. Dumke, CL, Pfaffenroth, CM, McBride, JM, and McCauley, GO.
Relationship between muscle strength, power and stiffness and
running economy in trained male runners. Int J Sports Physiol Perform
5: 249–261, 2010.
11. Ebben, WP and Petushek, EJ. Using the reactive strength index
modified to evaluate plyometric performance. J Strength Cond Res
24: 1983–1987, 2010.
12. Garcı
´a-Pinillos, F, Soto-Hermoso, VM, and Latorre-Roma
´n, PA.
Acute effects of extended interval training on
countermovement jump and handgrip strength performance in
endurance athletes: Postactivation potentiation. J Strength Cond Res
29: 11–21, 2015.
13. Garcı
´a-Pinillos, F, Soto-Hermoso, VM, and Latorre-Roma
´n, PA
´.
Acute physiological and thermoregulatory responses to
extended interval training in endurance runners:
Influence of athletic performance and age. J Hum Kinet 49: 209–
217, 2015.
14. Glatthorn, JF, Gouge, S, Nussbaumer, S, Stauffacher, S, Impellizzeri,
FM, and Maffiuletti, NA. Validity and reliability of optojump
photoelectric cells for estimating vertical jump height. J Strength
Cond Res 25: 556–560, 2011.
15. Harrison, AJ, Keane, SP, and Coglan, J. Force-velocity relationship
and stretch-shortening cycle function in sprint and endurance
athletes. J Strength Cond Res 18: 473–479, 2004.
16. Heiderscheit, BC, Chumanov, ES, Michalski, MP, Wille, CM,
and Ryan, MB. Effects of step rate manipulation on joint
mechanics during running. Med Sci Sports Exerc 43: 296–302,
2011.
17. Heise, GD and Martin, PE. Are variations in running economy in
humans associated with ground reaction force characteristics? Eur J
Appl Physiol 84: 438–442, 2001.
18. Higashihara, A, Ono, T, Kubota, J, Okuwaki, T, and Fukubayashi, T.
Functional differences in the activity of the hamstring muscles
with increasing running speed. J Sports Sci 28: 1085–1092, 2010.
19. Hudgins, B, Scharfenberg, J, Triplett, NT, and McBride, JM.
Relationship between jumping ability and running
performance in events of varying distance. J Strength Cond Res 27:
563–567, 2013.
20. Lee,MM,Song,CH,Lee,KJ,Jung,SW,Shin,DC,andShin,SH.
Concurrent validity and test-retest reliability of the OPTOGait
photoelectric cell system for the assessment of spatio-temporal
parameters of the gait of young adults. JPhysTherSci26: 81–85,
2014.
21. Lenhart, RL, Thelen, D, and Heiderscheit, B. Hip muscle loads
during running at various step rates. J Orthop Sports Phys Ther 44:
766–774, 2014. 1–4.
22. Lenhart, RL, Thelen, DG, Wille, CM, Chumanov, ES, and
Heiderscheit, BC. Increasing running step rate reduces
patellofemoral joint forces. Med Sci Sports Exerc 46: 557–564, 2014.
23. Mercer, JA, Devita, P, Derrick, TR, and Bates, BT. Individual effects
of stride length and frequency on shock attenuation during running.
Med Sci Sports Exerc 35: 307–313, 2003.
24. Mercer, JA, Vance, J, Hreljac, A, and Hamill, J. Relationship
between shock attenuation and stride length during
running at different velocities. Eur J Appl Physiol 87: 403–408,
2002.
Muscle Performance and Spatiotemporal Parameters
414
Journal of Strength and Conditioning Research
the
TM
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
25. Mooses,M,Mooses,K,Haile,DW,Durussel,J,Kaasik,P,and
Pitsiladis, YP. Dissociation between running economy and
running performance in elite Kenyan distance runners. J Sports
Sci 33: 136–144, 2015.
26. Morin, JB, Samozino, P, Zameziati, K, and Belli, A. Effects of altered
stride frequency and contact time on leg-spring behavior in human
running. J Biomech 40: 3341–3348, 2007.
27. Novacheck, TF. The biomechanics of running. Gait Posture 7: 77–95,
1998.
28. Nummela, A, Paavolainen, L, Sharwood, K, Lambert, M, Noakes, T,
and Rusko, H. Neuromuscular factors determining 5 km running
performance and running economy in well-trained athletes. Eur J
Appl Physiol 97: 1–8, 2006.
29. Paavolainen, L, Hakkinen, K, Hamalainen, I, Nummela, A, and
Rusko, H. Explosive-strength training improves 5-km running
time by improving running economy and muscle power. J Appl
Physiol (1985) 86: 1527–1533, 1999.
30. Pruyn, EC, Watsford, M, and Murphy, A. The relationship between
lower-body stiffness and dynamic performance. Appl Physiol Nutr
Metab 39: 1144–1150, 2014.
31. Santos-Concejero,J,Tam,N,Granados,C,Irazusta,J,
Bidaurrazaga-Letona, I, Zabala-Lili, J, and Gil, S. Stride angle as a
novel indicator of running economy in well-trained runners.
JStrengthCondRes28: 1889–1895, 2014.
32. Schieb, DA. Kinematic accommodation of novice treadmill runners.
Res Q Exerc Sport 57: 1–7, 1986.
33. Schubert,AG,Kempf,J,andHeiderscheit, BC. Influence of stride
frequency and length on running mechanics: A systematic
review. Sports Health 6: 210–217, 2014.
34. Tartaruga, MP, Brisswalter, J, Peyre
´-Tar t a r u g a , LA, A
´vila, AOV,
Alberton, CL, Coertjens, M, Cadore, EL, Tiggemann, CL,
Silva, EM, and Kruel, LF. The relationship between
running economy and biomechanical variables in
distance runners. Res Q Exerc Sport 83: 367–375, 2012.
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... Investigation of the relationship of spatiotemporal parameters with neuromuscular performance has shown different results [14,[43][44][45][46], suggesting that neuromuscular factors could influence running biomechanics through kinematic spatiotemporal parameters. However, there are no studies that relate these biomechanical parameters to the neuromuscular performance of highly trained female adolescent athletes. ...
... Regarding adaptations of spatiotemporal parameters after the increase in velocity, the results of this study reinforced the findings of previous studies [43,59,60]. Increased running speed has been shown to lead to a reduction in CT (to facilitate the progression of the leg during the oscillation phase to a new contact [59]) and to an increase in step frequency, as a spatiotemporal adaptation needed to run faster [61]. ...
... In addition, CT has been linked as a determinant of leg stiffness, with higher values of leg stiffness associated with shorter CT [61]. The increase in stride angle was also observed at a higher rate, agreeing with those obtained in previous studies [43,60]. ...
Article
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The purpose of this cross-sectional study was to analyse the relationship of neuromuscular performance and spatiotemporal parameters in 18 adolescent distance athletes (age, 15.5 ± 1.1 years). Using the OptoGait system, the power, rhythm, reactive strength index, jump flying time, and jump height of the squat jump, countermovement jump, and eight maximal hoppings test (HT8max) and the contact time (CT), flying time (FT), step frequency, stride angle, and step length of running at different speeds were measured. Maturity offset was determined based on anthropo-metric variables. Analysis of variance (ANOVA) of repeated measurements showed a reduction in CT (p < 0.000) and an increase in step frequency, step length, and stride angle (p < 0.001), as the velocity increased. The HT8max test showed significant correlations with very large effect sizes between neuromuscular performance variables (reactive strength index, power, jump flying time, jump height, and rhythm) and both step frequency and step length. Multiple linear regression found this relationship after adjusting spatiotemporal parameters with neuromuscular performance variables. Some variables of neuromuscular performance, mainly in reactive tests, were the predictors of spatiotemporal parameters (CT, FT, stride angle, and VO). Rhythm and jump flying time in the HT8max test and power in the countermovement jump test are parameters that can predict variables associated with running biomechanics, such as VO, CT, FT, and stride angle.
... The time component t stance is in itself relevant since a runner can only produce forces to propel the BCoM during the stance phase. For running speeds between 8 and 20 km/ h, t stance has a strong negative curvilinear relation with speed with values typically ranging between 0.34 and 0.18 seconds (Carrard et al., 2018;Chapman et al., 2012;Concejero et al., 2013;Dorn et al., 2012;Forrester & Townend, 2015;García-Pinillos et al., 2018;Hoyt et al., 2000;Nummela et al., 2007;Pavei et al., 2017;Roche-Seruendo et al., 2018;Da Rosa et al., 2019;De Ruiter et al., 2016;Weyand et al., 2000) (Figure 3). Due to the reduction in t stance with increasing speed, the GRF curves are compressed along the time axis, with increased force amplitudes to attain a sufficient impulse to maintain speed (I = ∫(F∆t) Dorn et al., 2012;Hamner & Delp, 2013;Nummela et al., 2007;Weyand et al., 2000). ...
... The manner in which t flight increases with running speed is described by a positive curvilinear relationship ( Figure 3) (Carrard et al., 2018;Concejero et al., 2013;García-Pinillos et al., 2018;Roche-Seruendo et al., 2018). Typically, t flight ranges between ~100 to 150 ms. ...
... Within 7 to 20 km/h, t flight is shorter than t stance . At high speeds, t flight seems to reach a maximum (Dorn et al., 2012;Mann et al., 2015;Nummela et al., 2007;Pavei et al., 2017;Roche-Seruendo et al., 2018;Da Rosa et al., 2019;Weyand et al., 2000). In consequence, since t stance decreases as a function of speed, t flight exceeds t stance at 'sprint' speeds around ~25 km/h (Nemtsev et al., 2015;Weyand et al., 2000). ...
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Running movements are parametrised using a wide variety of devices. Misleading interpretations can be avoided if the interdependencies and redundancies between biomechanical parameters are taken into account. In this synthetic review, commonly measured running parameters are discussed in relation to each other, culminating in a concise, yet comprehensive description of the full spectrum of running styles. Since the goal of running movements is to transport the body centre of mass (BCoM), and the BCoM trajectory can be derived from spatiotemporal parameters, we anticipate that different running styles are reflected in those spatiotemporal parameters. To this end, this review focuses on spatiotemporal parameters and their relationships with speed, ground reaction force and whole-body kinematics. Based on this evaluation, we submit that the full spectrum of running styles can be described by only two parameters, namely the step frequency and the duty factor (the ratio of stance time and stride time) as assessed at a given speed. These key parameters led to the conceptualisation of a so-called Dual-axis framework. This framework allows categorisation of distinctive running styles (coined ‘Stick’, ‘Bounce’, ‘Push’, ‘Hop’, and ‘Sit’) and provides a practical overview to guide future measurement and interpretation of running biomechanics.
... The influence of running velocity on spatiotemporal gait characteristics has been previously examined in the literature (Brughelli et al., 2010;Ogueta-Alday et al., 2014;Padulo et al., 2012;Roche-Seruendo et al., 2018). The overall decrease in the contact time (CT) and the increase in flight time (FT), step length (SL), and step frequency (SF) with increasing running speed have been previously shown (Brughelli et al., 2010;Ogueta-Alday et al., 2014;Padulo et al., 2012;Roche-Seruendo et al., 2018). ...
... The influence of running velocity on spatiotemporal gait characteristics has been previously examined in the literature (Brughelli et al., 2010;Ogueta-Alday et al., 2014;Padulo et al., 2012;Roche-Seruendo et al., 2018). The overall decrease in the contact time (CT) and the increase in flight time (FT), step length (SL), and step frequency (SF) with increasing running speed have been previously shown (Brughelli et al., 2010;Ogueta-Alday et al., 2014;Padulo et al., 2012;Roche-Seruendo et al., 2018). However, new devices for examining running biomechanics have arisen (e.g., OptoGait™ system) facilitating the assessment of new parameters, e.g., step angle [SA] (Santos-Concejero et al., 2014) and step variability (García-Pinillos et al., 2018a). ...
... The short duration of each running speed aimed to minimize the effect of fatigue on running kinematics and allowed participants to complete the test at running speeds at which amateur runners usually trained. This protocol was previously used by Roche-Seruendo et al. (2018). Participants verbally reported feeling comfortable while running on the treadmill at the set speeds. ...
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This study aimed to analyse the effects of running velocity on spatiotemporal parameters and step variability in amateur endurance runners, according to sex. A group of 51 males and 46 females performed an incremental running test on a treadmill (10-16 km/h). Spatiotemporal parameters (contact and flight time, step length, step frequency and step angle [CT, FT, SL, SF, SA]) and step variability, in terms of within-participant standard deviation (SD), were recorded through the OptoGait System. The ANOVA showed significant differences in the magnitude of the spatiotemporal parameters as running velocity increased (p < 0.001). It also revealed significant differences in step variability (p < 0.005) over the entire running protocol. Between-sex differences in CT, SL, SL-normalized and SF (p < 0.05, ES = 0.4-0.8) were found. Differences were also found in step variability at high velocities (15-16 km/h), with males showing a greater SD than females. In conclusion, increasing running velocity makes CT shorter, FT and SL longer, and SF and SA greater in amateur endurance runners, changing step variability, regardless of sex. Additionally, some between-sex differences were found in spatiotemporal parameters and step variability.
... This suggests that although one may be reactive over the sagittal plane (i.e., DJ), it may not reflect performances requiring reactiveness in both sagittal and horizontal planes (i.e., running). This statement seems to be supported by the specificity principle that claims that the task's demands define the type of SSC used and, hence, the RSI values [5,35,36], confirming consequently our hypothesis. ...
Article
Full-text available
Background: Musculotendinous reactive strength is a key factor for the utilization of elastic energy in sporting activities such as running. Aim: To evaluate the relationship between musculotendinous reactive strength and lower-limb stiffness during running as well as to identify age-related differences in both variables. Methods: Fifty-nine amateur endurance runners performed three 20-cm drop jumps and a constant 3-min easy run on a motorized treadmill. Reactive strength index and dynamic lower-limb stiffness were calculated with a photoelectric cell system by jumping and running, respectively. Additionally, sit to stand difference in plantar arch height was assessed as a static lower-limb stiffness measure. The cluster analysis allows the comparison between younger and older runners. Results: No significant correlations were found between jumping reactive strength and running lower-limb stiffness. The younger group performed better at drop jumps (p = 0.023, ES = 0.82), whereas higher-but-no-significant results were found for reactive strength index and stiffness-related metrics. Conclusions: Musculotendinous vertical reactiveness may not be transferred to combined vertical and horizontal movements such as running.
... La velocidad de carrera es una de las variables que más influencia el comportamiento biomecánico y neuromuscular [1], [5]. Sus características espacio temporales han sido S estudiadas generalmente con velocidades sobre los 10,00 km/h o 2,77 m/s [6]- [8]. Sin embargo, es limitada la evidencia acerca de la influencia de bajas velocidades correspondientes al rango donde se generan las transiciones de marcha a carrera (5-8km/h o 1,38-2,22m/s respectivamente) [5], sobre el comportamiento cinético y cinemático. ...
Article
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Introduction: Race speed is one of the variables that most influences biomechanical and neuromuscular behavior. The kinematic parameters have been studied generally with speeds over 10,00 km / h or 2,77 m / s and not at low speeds located in the transitions from walk to run (5-8km / h or 1,38-2,22m / s respectively). The objective of the study was to determine the influence of career speed on career run transition ranges on the kinematic variables Pronation Excursion and Pronation Velocity, obtained with a low-cost IMU for 60 seconds on a treadmill. Methods: A total of 40 non-symptomatic male participants (age 19,86 ± 1,02 years; body mass 70,58 ± 5,54 kg, BMI 23,45) voluntarily attended the study and performed two race conditions randomly assigned by a software These corresponded to running in a treadmill for 60 seconds at 5km / h and 8km / h without inclination. The subject was not informed when the IMU was read. Results: For the kinematic variables Pronation Excursion (º) and Pronation Velocity (º / s) compared in two speed conditions (5km / h and 8 km / h) statistically significant differences were found (p <0,05) with Cohen effect size large (> 0,8) for Pronation Velocity (° / s) and moderate for Pronation Excursion (º) Conclusions: The results suggest that changes in transition speed of 5km / h at 8km / h generate significant kinematic adaptations in the Pronation Excursion variables (º) and Pronation Velocity (º / s) evaluated with a low cost IMU. Clinicians are suggested to assess these variables when re-educating careers. Resumen-Introducción: La velocidad de carrera es una de las variables que más influencia el comportamiento biomecánico y neuromuscular. Los parámetros cinemáticos han sido estudiados generalmente con velocidades sobre los 10,00 km/h o 2,77 m/s y no así a bajas velocidades ubicadas en las transiciones de marcha a carrera (5-8km/h o 1,38-2,22m/s respectivamente). El objetivo de estudio fue determinar la influencia de la velocidad carrera en rangos de transición marcha carrera sobre las variables cinemáticas Pronation Excursion y Pronation Velocity, obtenidas con una IMU de bajo costo durante 60 segundos en una cinta rodante. Métodos: Un Total de 40 participantes hombres no sintomáticos (edad 19,86 ± 1,02 años; masa corporal 70,58 ± 5,54 kg, IMC 23,45) asistieron voluntariamente al estudio y realizaron dos condiciones de carrera aleatoriamente asignadas por un software. Estas correspondieron a correr en cinta rodante por 60 segundos a 5km/h y 8 km/h sin inclinación. El sujeto no fue informado cuando fue realizada la lectura del IMU. Resultados: Para las variables cinemáticas Pronation Excursion (º) y Pronation Velocity (º/s) comparadas en dos condiciones de velocidad (5 km/h y 8 km/h) se encontraron diferencias estadísticamente significativas(p<0,05) con tamaño del efecto de Cohen grande (>0.8) para Pronation Velocity (°/s) y moderado para Pronation Excursion(º) Conclusiones: Los resultados sugieren que cambios en la velocidad de 5km/h a 8 km/h generan adaptaciones cinemáticas significativas en las variables Pronation Excursion(º) y Pronation Velocity(º/s) evaluadas con un IMU de bajo costo. Se sugiere a los clínicos valorar estas variables al reeducar carrera.
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The biomechanics of walking and running, in both ground and treadmill conditions, have been extensively analysed and important differences have been reported. Despite some previous studies having examined the validity and reliability of the OptoGait™ system for measuring gait characteristics during walking, no previous works have determined the reliability and validity of this system while running on a treadmill. Therefore, this study aimed to determine the absolute reliability (within-subject variation) and evaluate the concurrent validity of the OptoGait™ system for measuring spatiotemporal variables while running at a comfortable speed by comparing data with a highly accurate system of measuring those parameters (i.e. video analysis at 1000 Hz). Forty-nine endurance runners performed a running protocol on a treadmill at a comfortable speed. Two systems were used to collect data: OptoGait™ system and high-speed video analysis at 1000 Hz. The coefficient of variation (CV) was calculated as a measure of absolute reliability. The OptoGait™ system reported a CV range between 2.2% and 11.4% for spatiotemporal parameters, while the video analysis showed a CV range between 0.02% and 9.9%. To determine concurrent validity, intra class correlation coefficients (ICC) and pairwise comparisons of means (t-test) were calculated between data from both systems. Although the paired t-test demonstrated significant differences between systems, a high level of agreement (ICC > 0.89) was obtained in spatiotemporal parameters between systems. When compared to a high-speed video analysis at 1000 Hz, the results indicate that the OptoGait™ system is a reliable and valid tool to measure spatiotemporal gait characteristics while running on a treadmill at a comfortable speed.
Conference Paper
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Assessing running shoes is confusing and there's a lot of controversial results in research. Mixing effects of different variables is quite common. In this conference I try to set up the mains variables that can confuse your results when assessing a running shoe biomechanics.
Thesis
The study of the spring-mass model variables in running resulted in a great contribution to the understanding of the behaviour of such model not only in humans, but in animals as well. Although the study of the running spatiotemporal parameters has contributed to obtain a deeper knowledge about the spring-mass model and its capacity to estimate and predict kinematic variables, the contribution of lower-limb stiffness to this model needed further research. The main aim of the present PhD Thesis was to determine the effect of various influential factors on lower-limb stiffness while treadmill running in healthy adults. Three different studies were executed to accomplish the main aim of this PhD Thesis: a unilateral cross-over study aiming at examining the test-retest reliability of the OptoGait photoelectric system for spatiotemporal parameters and lower-body stiffness analysis while treadmill running in healthy adults (Study 1). This first study is key as the entire development of this PhD Thesis has been based on the material and methods implemented and the findings reported; a unilateral cross-over study to clarify the likely relationship between reactive strength index while jumping and lower-limb stiffness while treadmill running in amateur endurance runners as well as sex differences (Study 2); and, ultimately, a unilateral cross-over study to identify the effects of footwear, foot-strike pattern, and step frequency on spatiotemporal parameters and lower-body stiffness (Study 3). The main findings derived from this PhD Thesis suggest that: the OptoGait system can be used confidently for running spatiotemporal parameters analysis and lower body stiffness at a constant velocity for healthy adults. The spring-mass model reacts differently to tasks based on their specificity principle. Additionally, sex-related differences must be considered when assessing the stretch-shortening cycle. Lower-limb stiffness responds differently to changes in footwear condition, foot-strike pattern, and step frequency. The findings reported here update the knowledge of lower-body stiffness while running and offer new scopes of action. A reliable and user-friendly system for running spatiotemporal parameters and lower-body stiffness analysis has been provided. Moreover, although both the SSC and lower-limb stiffness are key within the neuromuscular behaviour when elastic energy is used in sport, the specificity principle of each individual sporting task may make them behave differently; additionally, the menstrual cycle should be considered when working with female athletes since musculotendinous properties change over it. Ultimately, it is highly recommended to avoid measuring the effect of different variables on lower-limb stiffness individually as it has been shown that they influence each another, therefore, the behaviour of the spring-mass model when altering variables such as footwear, foot-strike pattern (FSP), and step frequency (SF) needs to be examined should be analysed attentively.
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Studies on running biomechanics and energetics are usually conducted on a treadmill. To ensure that locomotion on a treadmill is comparable to locomotion overground, participants need to be expert in the use of the device. This study aimed to identify the number and duration of sessions needed to obtain stable measurements for spatiotemporal and metabolic parameters in unexperienced treadmill runners. Fourteen male recreational runners performed three 15-min treadmill running trials in different days at a submaximal speed. Spatiotemporal and metabolic parameters were registered at minutes: 5, 10, 15 and their within-trial and between-trial changes were analysed using a two-way repeated measures ANOVA and Bonferroni post-hoc test. Within-trial differences were found in step frequency (decreased over time), Step Length and Contact Time (increased), reaching stability at different time points. Ventilator parameters increased, reaching stability after 5–10 min, while heart rate increased progressively over time. The only between-trial differences were an increase in step length and a decrease in step frequency at min 1, between trials 1 and 3. In conclusion, at least three running trials of 15 min are required to familiarize with the device. The last 5 min of the third trial can be regarded as stable measurements.
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Despite the widespread use of the OptoGait photoelectric cell system for the analysis of running spatiotemporal parameters, its reliability has not been proved. Consequently, this study intends to determine the test–retest reliability of the system when applied to treadmill running spatiotemporal parameters and lower body stiffness at a constant velocity. Amateur endurance runners (n = 31; age: 34.42 ± 9.26 years; height: 171.54 ± 9.15 cm; body mass: 66.63 ± 11.3 kg) voluntarily consented to participate in this study. Data for each participant were recorded twice per session across two testing sessions. The intra-session and inter-session reliabilities of spatiotemporal parameters and lower body stiffness were determined through test–retest analysis. Although mean comparisons revealed significant differences between measurements in spatiotemporal running gait characteristics and lower body stiffness for intra-session (p < 0.05 in all parameters), the effect size was always small (<0.4). Moreover, the relationship between measurements was very large for spatiotemporal parameters and lower body stiffness (r > 0.7). The intraclass correlation coefficients revealed an almost perfect correlation between measurements (intraclass correlation coefficients >0.81), except Kleg with substantial reliability (intraclass correlation coefficient = 0.788). The inter-session reliability revealed some significant differences in contact time (p = 0.009) and Kleg (p = 0.013), although Cohen’s d indicated small effect size (<0.31). The relationship between sessions was very large for spatiotemporal parameters and lower body stiffness (r > 0.8), and the intraclass correlation coefficients revealed an almost perfect inter-session association (intraclass correlation coefficients >0.881). The results found here show that the OptoGait system can be used confidently for running spatiotemporal parameters analysis and lower body stiffness at a constant velocity for healthy adults.
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Vertical jump is one of the most prevalent acts performed in several sport activities. It is therefore important to ensure that the measurements of vertical jump height made as a part of research or athlete support work have adequate validity and reliability. The aim of this study was to evaluate concurrent validity and reliability of the Optojump photocell system (Microgate, Bolzano, Italy) with force plate measurements for estimating vertical jump height. Twenty subjects were asked to perform maximal squat jumps and countermovement jumps, and flight time-derived jump heights obtained by the force plate were compared with those provided by Optojump, to examine its concurrent (criterion-related) validity (study 1). Twenty other subjects completed the same jump series on 2 different occasions (separated by 1 week), and jump heights of session 1 were compared with session 2, to investigate test-retest reliability of the Optojump system (study 2). Intraclass correlation coefficients (ICCs) for validity were very high (0.997-0.998), even if a systematic difference was consistently observed between force plate and Optojump (-1.06 cm; p < 0.001). Test-retest reliability of the Optojump system was excellent, with ICCs ranging from 0.982 to 0.989, low coefficients of variation (2.7%), and low random errors (±2.81 cm). The Optojump photocell system demonstrated strong concurrent validity and excellent test-retest reliability for the estimation of vertical jump height. We propose the following equation that allows force plate and Optojump results to be used interchangeably: force plate jump height (cm) = 1.02 × Optojump jump height + 0.29. In conclusion, the use of Optojump photoelectric cells is legitimate for field-based assessments of vertical jump height.
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This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity.
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Running economy (RE) is considered an important physiological measure for endurance athletes, especially distance runners. This review considers 1) how RE is defined and measured and 2) physiological and biomechanical factors that determine or influence RE. It is difficult to accurately ascertain what is good, average, and poor RE between athletes and studies due to variation in protocols, gas-analysis systems, and data averaging techniques. However, representative RE values for different caliber of male and female runners can be identified from existing literature with mostly clear delineations in oxygen uptake across a range of speeds in moderately and highly trained and elite runners. Despite being simple to measure and acceptably reliable, it is evident that RE is a complex, multifactorial concept that reflects the integrated composite of a variety of metabolic, cardiorespiratory, biomechanical and neuromuscular characteristics that are unique to the individual. Metabolic efficiency refers to the utilization of available energy to facilitate optimal performance, whereas cardiopulmonary efficiency refers to a reduced work output for the processes related to oxygen transport and utilization. Biomechanical and neuromuscular characteristics refer to the interaction between the neural and musculoskeletal systems and their ability to convert power output into translocation and therefore performance. Of the numerous metabolic, cardiopulmonary, biomechanical and neuromuscular characteristics contributing to RE, many of these are able to adapt through training or other interventions resulting in improved RE.
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The purpose of this study was to analyze multiple effects of an extended interval training (EIT) protocol on countermovement jump (CMJ) and handgrip strength in endurance athletes and to determine the relationship between fatigue and potentiation. Thirty experienced sub-elite male long-distance runners (age = 28.26 +/- 8.27 years, body mass index = 22.24 +/- 2.50 kg.m(-2), and VO(2)max = 58.7 +/- 4.50 ml.kg(-1).min(-1)) participated voluntarily in this study. Subjects performed the protocol on an outdoor running track, which consisted of 12 runs of 400 m, grouped into 4 sets of 3 runs, with a passive recovery of 1 minute between runs and 3 minutes between sets (4 3 3 3 400 m). During protocol, fatigue parameters (lactate, heart rate, and rate of perceived exertion) and performance parameters (CMJ, handgrip strength, and time spent in each 400-m run) were controlled. Analysis of variance revealed a significant improvement in CMJ (p < 0.001) throughout the protocol. Cluster analysis grouped according to whether potentiation was experienced (responders group, n = 17) or not (nonresponders group, n = 13) in relation to CMJ change from rest to fatigued condition at the end of activity. Responders group significantly improved (p <= 0.05) the performance in CMJ, handgrip strength and time spent in each 400-m run. Results suggest that despite induced fatigue for EIT, trained subjects can maintain their strength and power levels and their work capacity. This fact would support the rationale that improvements in performance may be due not only to metabolic adaptations but also to specific neuromuscular adaptations. Therefore, the evaluation of power should be considered simultaneously with running performance when monitoring endurance athletes.
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Study design: Controlled laboratory study, cross-sectional. Objectives To characterize hip muscle forces and powers during running, and to determine how these quantities change when altering step rate for a given running speed. Background: Hip musculature has been implicated in a variety of running-related injuries and, as such, is often the target of rehabilitation interventions, including resistance exercises and gait retraining. The differential contributions of the hip muscles to the task of running are not well understood, and may be important for recognizing the biomechanical mechanisms of running-related injuries and refining current treatment and prevention strategies. Methods: Thirty healthy participants ran at their preferred speed at 3 different step rates: 90%, 100%, and 110% of their preferred step rate. Whole-body kinematics and ground reaction forces were recorded. A 3-D musculoskeletal model was used to estimate muscle forces needed to produce the measured joint accelerations. Forces and powers of each muscle were compared across step-rate conditions. Results: Peak force produced by the gluteus medius during running was substantially greater than that of any other hip muscle, with the majority of muscles displaying a period of negative work immediately preceding positive work. The higher running step rate led to an increase in hip flexor, hamstring, and hip extensor loading during swing, but, conversely, substantially diminished peak force and work during loading response for several hip muscles, including the gluteal muscles and piriformis. Conclusion: Increasing running step rate for a given running speed heightened hamstring and gluteal muscle loading in late swing, while decreasing stance-phase loading in the gluteal muscles and piriformis. These results may enable clinicians to support and refine current treatment strategies, including exercise prescription and gait retraining for running-related injuries.
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Abstract The purpose of this study was to investigate the relationship between running economy (RE) and performance in a homogenous group of competitive Kenyan distance runners. Maximal aerobic capacity (VO2max) (68.8 ± 3.8 ml∙kg(-1)∙min(-1)) was determined on a motorised treadmill in 32 Kenyan (25.3 ± 5.0 years; IAAF performance score: 993 ± 77 p) distance runners. Leg anthropometry was assessed and moment arm of the Achilles tendon determined. While Achilles moment arm was associated with better RE (r(2) = 0.30, P = 0.003) and upper leg length, total leg length and total leg length to body height ratio were correlated with running performance (r = 0.42, P = 0.025; r = 0.40, P = 0.030 and r = 0.38, P = 0.043, respectively), RE and maximal time on treadmill (tmax) were not associated with running performance (r = -0.01, P = 0.965; r = 0.27; P = 0.189, respectively) in competitive Kenyan distance runners. The dissociation between RE and running performance in this homogenous group of runners would suggest that RE can be compensated by other factors to maintain high performance levels and is in line with the idea that RE is only one of many factors explaining elite running performance.
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