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Viscoelastic properties of lower extremity muscles after elite track cycling sprint events: a case report

Authors:
Sebastian Klich at Akademia Wychowania Fizycznego we Wrocławiu
Sebastian Klich
Igor Krymski at Akademia Wychowania Fizycznego we Wrocławiu
Igor Krymski
Adam Kawczyński at Akademia Wychowania Fizycznego im. Eugeniusza Piaseckiego w Poznaniu
Adam Kawczyński
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Abstract and Figures

Sprint cycling events require a high level of anaerobic capacity and, therefore, may affect peripheral fatigue throughout exercise-induced muscle damage. In fact, those alterations might decrease power generation. This study was performed on a 23 years old male elite track cyclist taking part in a sprint event. The measurements included power output (W) and cadence (rpm), lactate concentration (La-), heart rate (bpm), Rating of Perceived Exertion scale and viscoelastic properties analysis. The present study has shown a new approach to monitor the muscle properties of the lower extremity after 200 m flying start and repeated sprint races. Therefore, we hypothesized that repeated sprint races might lead to alterations in viscoelastic properties of lower extremity muscles. In track cycling, especially in sprint events, these variations may lead to increased muscle fatigue. Furthermore, training control and monitoring related to the assessment of muscles properties can be a source of counteracting injuries and relieving fatigue.
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Vol. 29, No. 1/2020
Central European Journal of Sport Sciences and Medicine | Vol. 29, No. 1/2020: 5–10 | DOI: 10.18276/cej.2020.1-01
VISCOELASTIC PROPERTIES OF LOWER EXTREMITY MUSCLES
AFTER ELITE TRACK CYCLING SPRINT EVENTS: A CASE REPORT
Sebastian Klich,1, A, B, D Igor Krymski,1, 2, A, B Adam Kawczyński1, A, B, D
1 University School of Physical Education in Wroclaw, Depar tment of Paralympic Sport, Poland
2 Polish Cycling Federation, National Team Coach, Andrzeja 1, 05 -800 Pruszków, Poland
A Study Design; B Dat a Collection; D Manuscript Preparation
Address for correspondence:
Sebastian Klich
University School of Physical Education in Wrocław, Department of Paralympic Sport
Witelona 25a, 51-617 Wrocł aw, Poland
E-mail: sebastian.klich@awf.wroc.pl
Abstract Sprint cycling events require a high level of anaerobic capacity and, therefore, may affect peripheral fatigue throughout
exercise-induced muscle damage. In fact, those alterations might decrease power generation. This study was performed on
a 23 years old male elite track cyclist taking part in a sprint event. The measurements included power output (W) and cadence
(rpm), lactate concentration (La-), heart rate (bpm), Rating of Perceived Exertion scale and viscoelastic properties analysis.
The present study has shown a new approach to monitor the muscle properties of the lower extremity after 200 m flying star t and
repeated sprint races. Therefore, we hypothesized that repeated sprint races might lead to alterations in viscoelastic properties
of lower extremity muscles. In track cycling, especially in sprint events, these variations may lead to increased muscle fatigue.
Furthermore, training control and monitoring related to the assessment of muscles properties can be a source of counteracting
injuries and relieving fatigue.
Key words viscoelastic properties, muscle stiffness, creep, 200 m flying, case report
Introduction
Sprint performance is dependent on maximal cycling power and is therefore susceptible to muscular fatigue
(Martin, Davidson, Pardyjak, 2007). Sprint cycling performance is mainly based on anaerobic metabolism derived
from phosphocreatine (PCr) which produces lactate. An increase in lactate accumulation may affect neuromuscular
activity and power generation, causing peripheral alterations in muscle fatigue. Moreover, mechanical and
morphological properties of lower extremity muscles may influence power production capabilities (Stafilidis,
Arampatzis, 2007).
Sprint races are one of the highest performance events in track cycling. They require maximal power output
and velocity generation (Klich, Krymski, Michalik, Kawczyński, 2018). S. Dorel et al. (2005) reported that elite 200 m
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6Central European Journal of Sport Sciences and Medicine
Sebastian Klich, Igor Krymski, Adam Kawczyński
flying start events ranged between 10 s and 11 s, while in our previous study (Klich et al., 2018), elite track cyclists
completed an averaged personal record below 10 s.
Previous studies have reported the negative effect of overloading as muscle degeneration (Kawczyński et al.,
2015; Klich et al., 2018). Therefore, an objective research protocol should be used to assess viscoelastic and
biomechanical properties in order to prevent the risk of overloading and injuries. Myotonometry is a reliable tool
for assessing the viscoelastic properties of muscles (Kawczyński et al., 2018; White, Abbott, Masi, Henderson,
Nair, 2018). In previous studies, myotonometry was used to assess muscle stiffness, elasticity and muscle tone
(Davidson, Bryant, Bower, Frawley, 2017). Moreover, it provides many quantitative data about muscle belly and
tendon stiffness after fatigue (Viir et al., 2007).
To the best of our knowledge, no study to date has used the viscoelastic properties of the lower extremity
muscles after a 200 m flying start and repeated sprints. These observations may provide a crucial understanding
of injury prevention, recovery protocols, and physical therapy treatment. Thus, the viscoelastic properties of lower
extremity muscles should be investigated after repeated sprint events.
Methods
Study design
An observational case study involved six repeated myotonometry measurements, namely: (1) before; (2) after
a 200 m flying start; (3–6) following each sprint. Viscoelastic properties of lower extremity muscles (e.g. muscle
tone, stiffness, decrement, relaxation time and creep) were investigated in anterior thigh muscles, hamstrings, tibia
muscles, and cuff muscles on the right (dominant) side. The participant read and signed an informed consent form
approved by the University Research Ethics Committee.
Participant
An elite track cyclist (age 23 years; body height 176.2 cm; body weight 85.8 kg; BMI 27.6 kg∙m-2) participated in
the study. The subject was a member of the National Track Cycling Team specializing in sprint events. The participant
was a medalist in international-level track races with a training experience of 11 years. The subject had not suffered
from an injury or pain within the past six weeks.
Experimental procedures
The experiment was prepared during a class 1 international event (men’s sprint), where the subject started
in a 200 m flying start and four sprint races. Sprint races were divided into qualifying (one race), quarterfinal (one
race), semifinals (two races) and finals (two races). During all races peak and averaged power output (POmax and
POmean) [W] and cadence (Cmax and Cmean) [rpm] were measured using PowerControl PC8 SRM (SRM GmbH,
Germany). Rest HR was assessed using a Polar M400, heart rate monitor (Polar Electro, Finland). During the
men’s sprint events measurements of: a) peak and averaged heart rate (HRmax and HRmean) [bpm]; b) blood lactate
(La-) [mmol·l-1] (Lactate Scout, SensLab GmbH, Germany); c) Borg rating of perceived exertion (RPE) – 20 point
scale; d) viscoelastic properties of the muscles (muscle tone, stiffness, decrement, relaxation time and creep)
(Myotonometer; MyotonPro, Myoton Ltd, Estonia); were taken at rest and in the 3rd minute after each race. Time
breaks between each stage were: 1) qualifying (200 m flying start) – quarterfinal (sprint 1) – 1st semifinal (sprint 2):
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Vol. 29, No. 1/2020
Muscle Mechanical Properties in Track Cycling Sprint Events
two hours; 2) 1st semifinal race (sprint 2) – 2nd semifinal race (sprint 3): 40 minutes; 3) 2nd semifinal race (sprint 3)
– 1st final race (sprint 4): 1 hour.
A handheld Myotometer device was used to measure the lower ex tremit y muscles viscoelastic properties
(muscle tone, stiffness decrement, relaxation time and creep). Myotonometry measurements were made on
the dominant lower extremity (right) at 23 reference points, including the anterior thigh muscles (points 1–7): rectus
femoris (points 1–2); tensor fasciae latae (point 3); vastus lateralis (points 4–6); vastus medialis (point 7); posterior
thigh muscles (points 8–15): external hamstrings (points 8–11); internal hamstrings (points 12–15); tibia muscles
(points 16–18): tibialis anterior (point 16); peroneus (points 17–18); and posterior cuff muscles (points 19–23);
external gastrocnemius (points 19–20); internal gastrocnemius (points 21–22); and soleus (point 23) muscles (Klich
et al., 2018). For this study, three measurements at each reference point were performed, and the mean calculated.
Measurement for one reference point took about 5 sec, while the total examination time was less than 2 min.
Results
The highest POmax and POmean were observed during the 200 m flying start and sprint 4 (1973 W; 1904 W;
1172 W and 1124 W, respectively). Cmax reached the highest value in sprint 4 (133 rpm), while Cmean during the 200
m flying start and sprint 2 (103 rpm and 104 rpm). The subject reached the highest HRmax noted during the 200 m
flying start and sprint 2 (195 bpm both), and HRmean in sprint 2 and 3 (184 bpm both). The highest La- was observed
during the 200 m flying start and sprint 4 (15.9 mmol·l–1 both). RPE increased during all starts, reaching the highest
in sprint 4 (19) (Table 1).
Table 1. Power output, cadence and physiological parameters after men’s sprints
Variables Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
POmax [W] – 1,973 1,632 1,778 1,668 1,904
POmean[W] – 1,172 1,034 1,045 1,103 1,124
Cmax [rpm] – 129 124 126 129 133
Cmean [rpm] – 103 100 104 102 94
HRmax [bpm] – 195 186 195 191 189
HRmean [bpm] 70 182 178 184 184 177
La- [mmol·l-1] 1.5 15.9 13.3 13.8 14.5 15.9
RPE 6 11 15 17 18 19
Abbreviations: POmax = maxim al power output [W ]; POmean = mean pow er output [W]; Cm ax = maximal cadenc y [rpm]; Cmean = mean ca dency [rpm]; HRmax = maximal heart rate
[bpm]; HRmean = mean hea rt rate [bpm]; La - = lactate concentration [mmol·l–1], RPE = Rat ing of Perceived Exertion.
The average muscle tone and stiffness increased after the 200 m flying start and sprint 1. The highest increase
in tone observed in the hamstrings (200 m – 33.6%) and cuff (sprint 1 – 38.0%), while stiffness in hamstrings
(200 m – 36.0% and sprint 1 – 47.7%). In sprint 2 we observed a decrease in muscle tone (an average of 19.0%)
and stiffness (an average of 24.4%). In the next sprints (sprint 3 and 4) we observed the highest increase in muscle
tone and stiffness in the tibia (tone – 20.4% and 24.6%; stiffness – 28.5% and 31.3%), and decrease in stiffness
(13.6% and 15.0%). The highest decrement was observed in 1st, 3rd and 4th sprints, especially in the anterior thigh
(36%; 39% and 52%, respectively) and tibia muscles (33%; 45% and 57%, respectively) (Figure 1a–c). The average
8Central European Journal of Sport Sciences and Medicine
Sebastian Klich, Igor Krymski, Adam Kawczyński
relaxation time and creep decreased after the 200 m flying start and sprint 1. The highest decrease in relaxation
time and creep observed in the hamstrings (R – 31.6% and 44.2%; C – 31.3% and 45.0%, respectively) and tibia
(R – 31.1% and 43.0%; C – 30.1% and 441%, respectively). The relaxation time of the hamstrings increased (sprint
2–4) (12.4% and 19.4%, respectively), however, decreased in the tibia (15.7% and 20.9%, respectively). The creep
decreased in both muscle groups (Figure 2a, b).
12
16
20
24
28
Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
Tone [Hz]
250
300
350
400
450
500
550
600
Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
Stiffness [N/m]
0.50
0.70
0.90
1.10
1.30
1.50
1.70
1.90
Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
Decrement
Anterior thigh Hamstrings
Tibia Cuff muscles
Figure 1. Muscle tone [Hz] (a), stiffness [N/m] (b) and decrement (c) after men’s sprint
a) b)
10
12
14
16
18
20
22
Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
Relaxation time [ms]
Anterior thigh Hamstrings
Tibia Cuff muscles
0.60
0.80
1.00
1.20
Rest 200 m Sprint 1 Sprint 2 Sprint 3 Sprint 4
Creep
Figure 2. Relaxation time (a) and muscle creep (b) after men’s sprint
a) b)
c)
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Vol. 29, No. 1/2020
Muscle Mechanical Properties in Track Cycling Sprint Events
Discussion
Experimental measurements have demonstrated that the 200 m flying start race had a considerable impact
as a substantial increase in muscle tone, stiffness, and a decrement in lower extremity muscles, especially in the
hamstrings and tibia muscles. However, an increase in muscle tone, stiffness, and a decrement in the tibia muscles
was observed after subsequent sprints. This event had the opposite result in muscle relaxation time and creep.
J. McDaniel et al. (McDaniel, Behjani, Elmer, Brown, Martin, 2014) have reported that during maximal
isokinetic cycling at 120 rpm, 49% of the power on the pedals was produced by the knee, 32% – by the hip, 9% – by
the ankle, and transferred across the hip. Moreover, J.C. da Silva et al. (2016) observed that the quadriceps muscle
and cuff muscle obtained the highest activity during cycling. Furthermore, the hamstrings can be activated during an
increase in pedal rate. After the 200 m flying start and the 1st sprint, there was an observed increase in muscle tone
and stiffness, while after the 2nd sprint a decrease in those parameters was found. The highest stiffness rate was
observed in the hamstrings. Additionally, in sprints 3 and 4 a greater muscle stiffness was obtained, except for the
hamstrings. R. Viir et al. (2007) reported a relationship between muscle tone and stiffness in the trapezius muscle.
Those observations should be considered based on pedal stroke. Simultaneously an increase in anterior thigh
stiffness is related to the propulsion phase, while during the downstroke phase the hamstrings and cuff muscles
reach the highest stiffness (Dorel et al., 2005). The highest increase in tibia muscle stiffness, as well as a decrease
in relaxation time and creep after the 3rd and the 4th sprint was caused probably by a high range of action (all the
range) and peak activity angle (280°) (Ryan, Gregor, 1992). A. White et al. (2018) found a correlation between
relaxation time and creep of lower lumbar erector spinae muscle. From the biomechanical point of view, as muscle
stiffness increases, relaxation time shortens, and less degree of creep is needed. Furthermore, stiffness is inversely
proportional to relaxation time, because the stiffer the tissue, the shorter time is needed to recover. According to
C.R. Abbiss et al. (Abbiss, Peiffer, Laursen, 2009), a sprint cyclist’s pedal rate should be about 100–120 rpm, as
it reduces neuromuscular fatigue. In our opinion, sprint tactics and increased muscle fatigue could influence the
alterations in viscoelastic properties. Increase in pedaling rate could be associated with greater activity of the
vastus medialis, medial hamstrings and the calf muscles. The last sprint (4th) was followed by a maximal cadence
of 133 rpm, while the mean cadence was 94 rpm. T. Takaishi et al. (Takaishi, Yasuda, Ono, Moritani, 1996) suggest
that lower pedaling rate may lead to worse blood flow and venous return in the muscles. An increase in decrement
could confirm our observations, because this parameter reflects muscle elasticity. Biomechanically, decrement is
inverse proportional to elasticity. A. White et al. (2018) have reported a positive correlation between muscle stiffness
and decrement. In our opinion, alterations in viscoelastic properties in the tibia muscles are related to increased
fatigue of the anterior thigh and cuff muscles (Klich et al., 2018).
Conclusion
The 200 m flying start and repeated sprint races appear to affect the viscoelastic properties of lower extremity
muscles in track cyclists. The increase of muscle tone, stiffness and decrement is followed by a decrease in
relaxation time and creep. This study has proved that the muscle fatigue mechanism is related to alterations in
viscoelastic properties. Moreover, fatigue mechanisms might influence muscle outcomes, e.g. muscle activation,
recruitment and fibers type. This research presents the individual results of a single athlete, yet the main findings
of the study could be useful information in programming specific workouts and recovery sessions.
10 Central European Journal of Sport Sciences and Medicine
Sebastian Klich, Igor Krymski, Adam Kawczyński
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Cite this article as: Klich, S., Krymski, I., Kawczyński, A. (2019). Viscoelastic Properties of Lower Extremity Muscles after Elite
Track Cycling Sprint Events: A Case Report. Central European Journal of Sport Sciences and Medicine, 1 (29), 5–10. DOI:
10.1827 6/cej. 202 0.1- 01. #1#
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Full-text available
  • Aug 2024
Track cycling events, both sprint and endurance, are primarily focused on performance of high and medium power durations, and it is suggested, measures of peak power govern performance in the sprint and pursuit cycling events. Various tests and metrics in the laboratory have been used to try and model track cycling. With the advent of power meters cyclists have been able to record power output in the field and several basic tests have evolved to use as a means to get started with training and racing with power. This thesis proposes a linear model based on total least squares regression, to evaluate these models and provide an option for coaches to see what durations are key for performance, and for sprint cyclists what types of training should be performed at a given part of a training build up. This analysis is applied to sprint cycling, male and female sprint cyclists, and pursuit cyclists to evaluate field-based data compared to lab and model derived metrics. The key conclusions from this thesis are: 1. For each specific power duration along the hyperbolic power-duration curve shows field-based data offers a better model for both sprint and pursuit durations. The linear model has a parabolic relationship the closer the inputs get to the specific duration assessed. 2. This disproves the contention of a linear process governed by peak power being the key metric of sprint cycling. The data in this thesis shows not only is this relationship incorrect, but strong relationships with sprint cycling durations hold for durations as long as 20-min. 3. This thesis finds there are sex differences for the model showing women have a higher variation of sprint power than men. 4. The linear model is applied to track endurance cycling to show, again, how a peak power (or maximal sprinting power or 𝑉̇O2max) does not govern performance, more a broad base of capacity reflected by a high lactate threshold, ventilatory threshold, critical power or other estimates of the maximal metabolic steady state. 5. Based on an understanding of the importance of capacity as well as peak power Chapter 6 shows this information can successfully be applied to the performance of sprint cyclists training towards peak performance.
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... However, the stiffness of the masseter muscle increased after the Exercise intervention, which was contrary to our expectations. This increase might be attributed to the exercise protocol inducing a higher blood flow, like a warm-up effect, rather than solely providing the stretching benefits typically associated with decreased muscle stiffness [33]. Similarly, the increase in tone following the Exercise intervention suggests a complex interplay of factors beyond simple mobilisation, potentially involving enhanced muscle temperature and performance improvements, as seen in other studies on muscle rigidity. ...
Acute Myotonometric Changes in the Masseter and Upper Trapezius Muscles After Upper Body Quarter Stretching and Coordination Exercises or Chewing
Article
Full-text available
  • Jan 2025
Pathologies in neck and masticatory muscles affect muscle tone and biomechanical and viscoelastic properties, necessitating precise assessment for treatment. This study evaluated the impact of two guided interventions—relaxing exercises targeting the neck and masticatory muscles (“Exercise”) and heavy chewing using six chewing gums (“Chewing”)—on the masseter and upper trapezius muscles. Twelve participants (aged 19–40 years) underwent myotonometric assessment pre- and post-intervention, measuring tone, stiffness, decrement, relaxation time, and creep. The results showed significant changes in the masseter muscle after exercise, with increased stiffness (14.46%, p < 0.001) and tone (7.03%, p < 0.001) but decreased creep (−9.71%, p < 0.001) and relaxation time (−11.36%, p < 0.001). Conversely, chewing decreased stiffness (−8.82%, p < 0.001) and tone (−5.53%, p < 0.001), while it increased creep (9.68%, p < 0.001) and relaxation time (9.98%, p < 0.001). In the trapezius muscles, tone decreased after both interventions (Exercise: −7.65%, p < 0.001; Chewing: −1.06%, p = 0.003), while relaxation increased (Exercise: 1.78%, p < 0.001; Chewing: 2.82%, p < 0.001). These findings reveal the distinct effects of exercise and chewing on muscle properties, emphasising the complexity of their therapeutic potential and the need for further investigation.
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... In the present study, no differences in muscle viscoelastic properties (i.e., stiffness, oscillation frequency, and the logarithmic decrement of tissue oscillation) occurred, which is in line with our hypothesis. Changes in stiffness or muscle tone most often have corresponded with a decrease in performance and accumulation of fatigue (Klich et al., 2020;Wang, 2016 and showed augmented muscle stiffness of the triceps brachii post-exercise in comparison to pre-exercise measures after performing the bench press exercise with the maximal number of repetitions (70% 1RM). Furthermore, Trybulski et al. (2022a) reported a trend for augmented stiffness of the triceps brachii and decreased bar velocity during the bench press exercise (70% 1RM) performed to failure. ...
Acute Impact of Different Reperfusion Duration Following Blood Flow Restriction on Bar Velocity during the Bench Press Exercise
Article
Full-text available
The main goal of this study was to evaluate the effects of different reperfusion duration following intra-conditioning blood flow restriction (BFR) on bar velocity during the bench press exercise and muscle viscoelastic properties of the triceps brachii. Eleven resistance trained males (age: 24.3 ± 4.9 years; body mass: 85.5 ± 13.2 kg; bench press 1RM: 123.6 ± 25.4 kg; training experience: 6.8 ± 5.1 years) volunteered for the study. During experimental sessions participants performed 5 sets of 3 repetitions of the bench press exercise with a load of 60% 1RM under four different conditions: two BFR (80% AOP) and two control conditions. For the BFR conditions, cuffs were applied before each set for 4.5 min and released 30 or 60 s before the start of the set as reperfusion. Under the control conditions, BFR was not applied and the total duration of rest intervals amounted to 5 min and 5.5 min. Measurements of viscoelastic properties were conducted at baseline and immediately after completion of each set of the bench press exercise. The two-way ANOVA showed no significant condition × set interaction for mean and peak bar velocity (p = 0.93; p = 0.787; accordingly), and no main effect of condition for mean and peak bar velocity (p = 0.57; p = 0.417; accordingly). The Friedman's test showed no differences in oscillation frequency (p = 0.156), stiffness (p = 0.368), and the logarithmic decrement of tissue oscillation (p = 0.644). The results of this study indicate that BFR during rest intervals does not acutely influence mean and peak bar velocity, as well as mechanical properties of the triceps brachii regardless of the duration of reperfusion.
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... In another study, the mechanical properties of patellar tendons were assessed in track cyclists, with the use of ultrasonography and myotonometry [23]. Significantly higher values of patellar tendon stiffness were observed in sprinters, as compared to individuals practicing endurance sports. ...
Mechanical Properties of the Patellar Tendon in Weightlifting Athletes - the Utility of Myotonometry
Article
  • Jun 2024
  • Acta Bioeng Biomech
Purpose Tendons adapt to loads applied to them, by changing their own mechanical properties. The purpose of the study was to examine the influence of practicing sport in the form of weightlifting/strength training by individuals of various age groups upon the mechanical properties of the patellar tendon. Methods 200 people participated in the study. Group 1 (n=109) comprised individuals training strength sports as amateurs, group 2 (n=91) consisted of people who were not physically active. The patellar tendon was examined in various positions of the knee joint: 0°, 30°, 60°, 90°, 120° respectively. The following mechanical parameters were measured with the use of a device for myotonometric measurements, MyotonPRO: frequency [Hz], stiffness [N/m], decrement [log], relaxation time [ms] and creep [De]. The results were compared as regards physical activity, training history, BMI value, and gender. Results Stiffness and tension increased while elasticity decreased with patellar tendon extension/stretching degree. In the group of individuals in training, greater stiffness and tension and lower elasticity were noted. Moreover, stiffness and tension appeared to be higher in elderly people and individuals with longer training experience. Conclusions Mechanical loads connected with strength training result in development of adaptive changes in the patellar tendon, in the form of higher stiffness and tension, as well as lower elasticity. The MyotonPRO device is useful for quantitative assessment of the mechanical properties of patellar tendon.
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... In the field of sports, objective methods of muscle tone assessment make it possible to investigate the influence of individual types of loads or even specific sports on the muscular apparatus or the rheological properties of the muscle. Myoton has been used for this purpose in many cases, either to measure the immediate effect (i.e., before and after exercise) [131][132][133][134] or to determine the long-term effect. The latter has been determined either by measuring it in a single individual before, during, and after a training program [135], or by simply comparing values in a specific group of athletes with the general population [136,137]. ...
Objective Methods of Muscle Tone Diagnosis and Their Application—A Critical Review
Article
Full-text available
“Muscle tone” is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.
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... The APR and CP models may provide a useful means of predicting the power-duration relationship in the extreme exercise intensity domain, such as during sprint track cycling events Leo et al. [35]. It is questionable whether it is necessary to run multiple trials to predict performance given the ease of measuring actual performance [36], modelling the determinants from actual performance [7,37], and measuring performance with various sensors, especially power output, during competition [38]. ...
Power-duration relationship comparison in competition sprint cyclists from 1-s to 20-min. Sprint performance is more than just peak power
Article
Full-text available
Current convention place peak power as the main determinant of sprint cycling performance. This study challenges that notion and compares two common durations of sprint cycling performance with not only peak power, but power out to 20-min. There is also a belief where maximal efforts of longer durations will be detrimental to sprint cycling performance. 56 data sets from 27 cyclists (21 male, 6 female) provided maximal power for durations from 1-s to 20-min. Peak power values are compared to assess the strength of correlation (R²), and any relationship (slope) across every level. R² between 15-s– 30-s power and durations from 1-s to 20-min remained high (R² ≥ 0.83). Despite current assumptions around 1-s power, our data shows this relationship is stronger around competition durations, and 1-s power also still shared strong relationships with longer durations out to 20-min. Slopes for relationships at shorter durations were closer to a 1:1 relationship than longer durations, but closer to long-duration slopes than to a 1:1 line. The present analyses contradicts both well-accepted hypotheses that peak power is the main driver of sprint cycling performance and that maximal efforts of longer durations out to 20-min will hinder sprint cycling. This study shows the importance and potential of training durations from 1-s to 20-min over a preparation period to improve competition sprint cycling performance.
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... Sports injuries seriously restrict the development of high-level sports teams in colleges and universities. 5,6 With the increase of competitions at different levels and types, athletes will be overwhelmed under the increasingly fierce competition. The load from the psychological body will break the physical and mental defense lines of athletes, causing sports injuries of different degrees, The systematic training of athletes has been broken, so it is urgent to develop a set of targeted physical training system, and effectively reduce the probability of athletes' sports injury and muscle injury. ...
MUSCLE INJURIES AND RECOVERY TRAINING IN COLLEGE SPRINTERS
Article
Full-text available
  • Mar 2023
Introduction The sprint is extremely explosive, and inadequate training methods can cause irreversible muscle damage. Objective Explore the types of sports injuries, the main sites, the main factors affecting the results of physical training, and the main factors affecting recovery from muscle injuries in college and university sprinters, and propose preventive measures. Methods Taking 174 college sprinters as the research object, we analyzed the conditions related to muscle injury and physical training of sprinters, using field investigation, questionnaire survey, and mathematical statistics. The types of sports injuries, the main sites, the main factors affecting the results of physical training, and the main factors affecting college sprinters’ recovery from muscle injury were investigated. Results Among the 174 athletes surveyed, 47.7% had sports injuries of different degrees, and 52.3% had no sports injuries. Different physical training methods, training time, training levels, and slack fatigue training can affect physical training results. Conclusion College sprinters should improve their safety awareness, give importance to preparatory activities and flexibility exercises, optimize strength training programs, and use physical and exercise therapy to promote recovery from muscle injuries. Level of evidence II; Therapeutic studies - investigation of treatment outcomes. Sports Injuries; Physical Fitness; Fatigue; Physical Education and Training
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Quadriceps and hamstring muscle activity during cycling as measured with intramuscular electromyography
Article
Full-text available
  • Sep 2016
  • EUR J APPL PHYSIOL
Purpose The aim of this study was to describe thigh muscle activation during cycling using intramuscular electromyographic recordings of eight thigh muscles, including the biceps femoris short head (BFS) and the vastus intermedius (Vint). Methods Nine experienced cyclists performed an incremental test (start at 170 W and increased by 20 W every 2 min) on a bicycle ergometer either for a maximum of 20 min or to fatigue. Intramuscular electromyography (EMG) of eight muscles and kinematic data of the right lower limb were recorded during the last 20 s in the second workload (190 W). EMG data were normalized to the peak activity occurring during this workload. Statistical significance was assumed at p ≤ 0.05. Results The vastii showed a greater activation during the 1st quadrant compared to other quadrants. The rectus femoris (RF) showed a similar activation, but with two bursts in the 1st and 4th quadrants in three subjects. This behavior may be explained by the bi-articular function during the cycling movement. Both the BFS and Vint were activated longer than, but in synergy with their respective agonistic superficial muscles. Conclusion Intramuscular EMG was used to verify muscle activation during cycling. The activation pattern of deep muscles (Vint and BFS) could, therefore, be described and compared to that of the more superficial muscles. The complex coordination of quadriceps and hamstring muscles during cycling was described in detail.
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Functional connectivity between core and shoulder muscles increases during isometric endurance contractions in judo competitors
Article
Full-text available
  • Jan 2015
The aim of this study was to assess the surface electromyogram (SEMG) changes within and between muscles of the torso and shoulder region during static endurance contraction in elite judokas. We hypothesized an increased functional connectivity of muscles from the shoulder and torso regions during sustained isometric contraction. Twelve healthy, right-handed judo competitors participated in the study. The SEMG signals from the dominant trapezius (upper, middle and lower part), deltoideus anterior, serratus anterior, and pectoralis major muscles were recorded during isometric endurance contraction consisting of bilateral arm abduction at 90°. The normalized mutual information (NMI) was computed between muscle pairs as an index indicating functional connectivity. The NMIs increased significantly during endurance test for 10 of the 15 muscle pairs (P < 0.001). We concluded that the increases in NMIs highlighted functional changes in the interplay between core and shoulder muscles during an endurance contraction in elite judokas.
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Optimal cadence selection during cycling
Article
Full-text available
  • Mar 2009
  • INT SPORTMED J
Cadence or pedal rate is widely accepted as an important factor influencing economy of motion, power output, perceived exertion and the development of fatigue during cycling. As a result, the cadence selected by a cyclist's could have a significant influence on their performance. Despite this, the cadence that optimises performance during an individual cycling task is currently unclear. The purpose of this review therefore was to examine the relevant literature surrounding cycling cadence in order provide a greater understanding of how different cadences might optimise cycling performance. Based on research to date, it would appear that relatively high pedal rates (100-120rpm) improve sprint cycling performance, since muscle force and neuromuscular fatigue are reduced, and cycling power output maximised at such pedal rates. However, extremely high cadences increase the metabolic cost of cycling. Therefore prolonged cycling (i.e. road time trials) may benefit from a slightly reduced cadence (~90-100rpm). During ultra-endurance cycling (i.e. >4h), performance might be improved through the use of a relatively low cadence (70-90rpm), since lower cadences have been shown to improve cycling economy and lower energy demands. However, such low cadences are known to increase the pedal forces necessary to maintain a given power output. Future research is needed to examine the multitude of factors known to influence optimal cycling cadence (i.e. economy, power output and fatigue development) in order to confirm the range of cadences that are optimal during specific cycling tasks.
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Trapezius muscle tone and viscoelastic properties in sitting and supine positions
Article
Full-text available
  • Jan 2007
OBJECTIVES: In this study, the aim was to use the upper trapezius muscle as a representative of the musculoskeletal support system to determine the effect of changing from a sitting position to a lying position on muscle tension and whether this change could be useful in the prevention of musculoskeletal complaints. METHODS: Fifteen healthy right-handed female computer operators participated in this study. Myometric measurements of the upper trapezius muscle on both sides of the body were recorded for the participants while they were in a sitting position and then again in a supine position. RESULTS: Changing from a sitting position to a supine position reduced the tone and stiffness by up to one-fifth—important characteristics of the support function—in the upper trapezius muscle. CONCLUSIONS: The change in the tone and stiffness of the trapezius muscle is of significance to the well-being of sedentary workers, particularly computer-terminal operators. Including recommended regular breaks of brief periods of simple, unchallenging movements while in a supine position should enhance their recovery from prolonged sitting because the support requirement on the muscles is lessened.
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Biomechanical properties of low back myofascial tissue in younger adult ankylosing spondylitis patients and matched healthy control subjects
Article
  • Jun 2018
  • CLIN BIOMECH
Background: Ankylosing spondylitis is a degenerative and inflammatory rheumatologic disorder that primarily affects the spine. Delayed diagnosis leads to debilitating spinal damage. This study examines biomechanical properties of non-contracting (resting) human lower lumbar myofascia in ankylosing spondylitis patients and matched healthy control subjects. Methods: Biomechanical properties of stiffness, frequency, decrement, stress relaxation time, and creep were quantified from 24 ankylosing spondylitis patients (19 male, 5 female) and 24 age- and sex-matched control subjects in prone position on both sides initially and after 10 min rest. Concurrent surface electromyography measurements were performed to ensure resting state. Statistical analyses were conducted, and significance was set at p < 0.05. Findings: Decreased lumbar muscle elasticity (inverse of decrement) was primarily correlated with disease duration in ankylosing spondylitis subjects, whereas BMI was the primary correlate in control subjects. In ankylosing spondylitis and control groups, significant positive correlations were observed between the linear elastic properties of stiffness and frequency as well as between the viscoelastic parameters of stress relaxation time and creep. The preceding groups also showed significant negative correlations between the linear elastic and viscoelastic properties. Interpretation: Findings indicate that increased disease duration is associated with decreased tissue elasticity or myofascial degradation. Both ankylosing spondylitis and healthy subjects revealed similar correlations between the linear and viscoelastic properties which suggest that the disease does not directly alter their inherent interrelations. The novel results that stiffness is greater in AS than normal subjects, whereas decrement is significantly correlated with AS disease duration deserves further investigation of the biomechanical properties and their underlying mechanisms.
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Effect of short-term cold-water immersion on muscle pain sensitivity in elite track cyclists
Article
  • May 2018
Objective: To determine the effect of short-term cold-water immersion (CWI) on muscle pain sensitivity after maximal anaerobic power training in track cyclists. Design: Repeated measures. Setting: University Laboratory. Participants: 12 elite sprint track cyclists (age 24,75 ± 4,23 years). Main outcome measures: PPT measurements were made on dominant lower extremity (right) in 20 reference points, including anterior thigh muscles, posterior thigh muscles and posterior cuff muscles. PPT levels were measured: 1) before workout, 2) immediately after workout, but before CWI 3) 1 h after CWI and 4) 12 h after CWI. Mean PPT values for each muscle group per participant were calculated for further statistical analysis. Results: The average PPT for anterior thigh muscles decreased significantly after effort (p ¼ 0.001) and increased significantly 1 h after CWI (p ¼ 0.048). In posterior thigh muscles PPT decreased significantly after effort (p ¼ 0.014) and increased significantly 1 h and 12 h after CWI (p ¼ 0.045 and p ¼ 0.25 respectively). However, in posterior cuff muscles PPT decreased only after effort (p ¼ 0.001). Conclusions: Short-term repeated sprint exercise appears to affect PPT in track cyclists. This study have reported that CWI in 5 �C for 5 min have had a beneficial effect in minimizing PPT 1 h post repeated maximal sprint training.
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Trapezius viscoelastic properties are heterogeneously affected by eccentric exercise
Article
  • Feb 2018
  • J SCI MED SPORT
Objectives: The aim of this study was to investigate the influence of eccentric exercise (ECC) on the spatial mapping of muscle stiffness and creep of the upper trapezius, using a quantitative myotonometry device. Design: Two groups of 16 subjects participated in the experimental sessions. In part A, the test-retest reliabilities of muscle stiffness and creep were assessed. In part B, muscle stiffness and muscle creep were mapped before, immediately after and 24h after ECC when post-exercise soreness had developed. Methods: The ECC protocol consisted of 50 eccentric contractions divided into 5 bouts of 10 contractions at maximum force level. Results: The relative reliabilities of stiffness and creep measurements were found to be substantial to almost perfect. Muscle stiffness for musculotendinous sites increased at 24h after ECC while it decreased for muscle belly immediately after and 24h after ECC. Muscle creep for musculotendinous sites decreased, and for muscle belly sites increased, immediately after and 24h after ECC. Conclusions: For the first time, the present study showed sign of discrepancies in the effects of ECC on muscle stiffness and creep, underlining opposite changes in the musculotendinous and muscle belly viscoelastic properties of upper trapezius.
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Myotonometry Reliably Measures Muscle Stiffness in the Thenar and Perineal Muscles
Article
  • May 2017
Purpose: The authors investigated the reliability of myotonometry-measured muscle tone in the thenar and perineal muscles. Methods: Participants were women aged 18-50 years who were asymptomatic for thumb and pelvic floor dysfunction (interrater study n=20; intrarater study n=43) or who were symptomatic for vulvodynia (interrater study n=14; intrarater study n=32). Mechanical properties (stiffness, frequency, decrement, relaxation time, and creep) of the muscles were measured using a myotonometer (MyotonPRO) while the muscles were in a relaxed state. Measures were performed twice by two assessors. Intra- and interrater reliability were determined using intra-class correlation coefficients (ICCs) and absolute reliability using the standard error of measurement and a minimum detectable change. Results: The primary property of interest, muscle stiffness, showed very good interrater (ICC 0.85-0.86) and intrarater (ICC 0.82-0.88) reliability in the thenar eminence. In the perineal muscles, reliability results ranged from good to very good for interrater (ICC 0.70-0.86) and intrarater (ICC 0.80-0.91) reliability for muscle stiffness. Absolute reliability was confirmed, with all measures showing minimal variance. Conclusions: Muscle stiffness of the smaller muscles of the body can be reliably measured using the MyotonPRO. The device could be used as a reference standard in the development of a digital palpation scale that would facilitate accurate diagnosis of muscle tone.
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Joint-Specific Power-Pedaling Rate Relationships During Maximal Cycling
Article
  • Mar 2014
Previous authors have reported power-pedaling rate relationships for maximal cycling. However, the joint-specific power-pedaling rate relationships that contribute to pedal power have not been reported. We determined absolute and relative contributions of joint-specific powers to pedal power across a range of pedaling rates during maximal cycling. Ten cyclists performed maximal 3s cycling trials at 60, 90, 120, 150, and 180 rpm. Joint-specific powers were averaged over complete pedal cycles, and extension and flexion actions. Effects of pedaling rate on relative joint-specific power, velocity and excursion were assessed with regression analyses and repeated measures ANOVA. Relative ankle plantar flexion power (25 to 8%; p=0.01; R2=0.90) decreased with increasing pedaling rate whereas relative hip extension power (41 to 59%; p<0.01; R2=0.92) and knee flexion power (34 to 49%; p < 0.01; R2=0.94) increased with increasing pedaling rate. Knee extension powers did not differ across pedaling rates. Ankle joint angular excursion decreased with increasing pedaling rate (48 to 20º) whereas hip joint excursion increased (42 to 48º). These results demonstrate that the often reported quadratic power-pedaling rate relationship arise from combined effects of dissimilar joint-specific power-pedaling rate relationships. These dissimilar relationships are likely influenced by musculoskeletal constraints (i.e., muscle architecture, morphology) and/or motor control strategies.
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EMG profiles of lower extremity muscles during cycling at constant workload and cadence
Article
  • Dec 1992
  • J ELECTROMYOGR KINES
Limited conclusions concerning the variability in EMG patterns during cycling can be made from available data in the literature because of methodological differences which include electrode placement and experimental design. The purpose of this study was to monitor EMG signals from ten lower extremity muscles over a large number of pedalling cycles in experienced cyclists at constant workload and cadence. Variability across subjects was evaluated by calculating the coefficient of variation (CV) at 10% intervals of the pedalling cycle. Within subject EMG patterns were very consistent within a single trial. The single-joint hip and knee extensors (gluteus maximus, vastus medialis, and vastus lateralis) had the lowest CV values (less than 30%). This low variability appears to support their role as power generators. Variability was generally higher in the hamstring muscles with two biceps femoris patterns emerging despite relatively similar experimental conditions. EMG signals from surface and fine wire electrodes for the hamstring muscles were compared for possible contribution to the discrepancies in the EMG profiles. Fine wire EMG data were quite similar to those obtained using surface electrodes, indicating that crosstalk had minimal effect, in general, on the hamstring signals. The tibialis anterior, gastrocnemius, and soleus muscles displayed fairly repeatable patterns, with variability highest in the first 20% of the pedalling cycle for all muscles studied.
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