Musculotendinous Adaptations to Strength and Endurance Training in Cyclists (STEND)

June 16, 2026 updated by: Lithuanian Sports University

Transient Neuromuscular and Muscle-Tendon Adaptations Following Strength vs Endurance-Only Training in Competitive-Level Cyclists

This study investigated whether adding strength training to regular endurance training improves performance and muscle function in competitive cyclists. Endurance training is essential for cycling performance, while strength training has been widely recognised as a complementary strategy that may enhance performance and reduce injury risk. However, in practice, strength training is often performed only during limited periods of the training season, and it remains unclear to what extent the adaptations achieved are maintained during subsequent phases of endurance-focused training.

Male competitive cyclists were assigned to either a 10-week off-season combined strength and endurance training programme or an endurance-only training programme. The strength training group performed two weekly strength sessions in addition to their usual cycling training, while the control group continued with endurance training only.

Participants were assessed at four time points: before the intervention, after the initial 10-week training period, after a high-volume endurance training camp, and during a competition preparation phase. Measurements included body composition, muscle strength, explosive force production, muscle and tendon structure, and cycling performance variables such as maximal power output and aerobic capacity.

The primary aim of the study was to determine whether short-term strength training enhances neuromuscular performance and muscle-tendon characteristics in trained cyclists, and whether these adaptations are maintained or reduced when strength training is discontinued. A secondary aim was to examine how these changes interact with endurance adaptations across different phases of the training season.

It was hypothesised that strength training would improve muscle strength, power, and muscle-tendon structure, but that these adaptations would be partially reduced during subsequent training phases without continued strength stimulus.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study was designed to investigate the effects of adding a short-term strength training intervention to regular endurance training in competitive cyclists, with a particular focus on neuromuscular, muscle-tendon, and performance adaptations across different phases of the training season. The study also aimed to examine the persistence of these adaptations during subsequent periods characterised by endurance-only training.

The intervention was implemented during the off-season period and consisted of a 10-week training phase in which participants completed either a combined strength and endurance programme (ST) or an endurance-only programme (END). The strength training programme was integrated into the athletes' regular training routine and included two weekly sessions targeting major lower-limb muscle groups, with the objective of improving maximal strength and explosive force production. Training load and content were aligned with the athletes' overall training plans to ensure ecological validity within a competitive cycling context.

Following this initial training phase, all participants continued with their regular endurance training through two distinct phases of the competitive season. The first phase consisted of a high-volume endurance training camp, primarily aimed at increasing training load and aerobic conditioning. The second phase corresponded to a competition preparation period, characterised by adjustments in training intensity and volume to optimise performance for competition. This sequential design allowed the assessment of both the development and the retention of adaptations induced by strength training under realistic training conditions.

A comprehensive non-invasive testing battery was implemented to capture adaptations across multiple physiological and performance domains. Neuromuscular assessments included measures of maximal strength, maximal voluntary contraction, rate of force development, and sprint-specific mechanical variables. Muscle-tendon characteristics were evaluated using imaging-based assessments of quadriceps muscle thickness and patellar tendon morphology. In addition, cycling-specific performance was assessed through measures of maximal power output, sprint performance, aerobic capacity, and gross efficiency. Anthropometric measurements were also collected to monitor potential changes in body composition.

The study was conducted using a repeated-measures design with multiple time points spanning the transition from the off-season to the competition period. This approach enabled the evaluation of both short-term training effects and their evolution over time. Particular emphasis was placed on understanding the interaction between strength training-induced adaptations and subsequent endurance training stimuli, as well as the extent to which neuromuscular and structural adaptations are maintained in the absence of continued strength training.

Overall, the study provides a comprehensive evaluation of the role of strength training in endurance-trained athletes, addressing both its effectiveness as a complementary training modality and the temporal stability of the adaptations it induces within a typical competitive season.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
24

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Lithuania
      • Kaunas, Lithuania, LT-44221
        • Lithuanian Sports University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male competitive cyclist
  • Aged 18 to 40 years
  • Minimum of 3 years of structured cycling training experience
  • Actively competing during the previous cycling season
  • Following a structured training programme with planned competitions
  • Able to participate in all training sessions and testing procedures
  • Free from medical conditions contraindicating high-intensity exercise

Exclusion Criteria:

  • Current musculoskeletal injury or pain affecting training or performance
  • History of major lower-limb injury within the past 10 years
  • Presence of any cardiovascular, neurological, or metabolic disease
  • Use of medications that may affect physical performance or training adaptations
  • Inability to comply with the training programme or testing schedule
  • Participation in another structured strength training programme during the study period

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Endurance Training (END)
Endurance training group, performing their classical training routine
Behavioral: Endurance training
The endurance-only group continued their usual cycling training without additional strength training. Following the intervention, all participants performed endurance-only training during a high-volume training camp and a subsequent competition preparation phase.
Other Names:
  • Endurance only training
Experimental: Strength + Endurance Training (ST)
Strength training group, performing 10-weeks off-season strength training (2 session/week) in addition to their endurance training routine.
Behavioral: Endurance training
The endurance-only group continued their usual cycling training without additional strength training. Following the intervention, all participants performed endurance-only training during a high-volume training camp and a subsequent competition preparation phase.
Other Names:
  • Endurance only training
Behavioral: Strength training
Participants allocated to the combined strength and endurance training group completed two supervised strength training sessions per week for 10 weeks in addition to their habitual cycling training. The strength programme targeted major lower-limb muscle groups (e.g., quadriceps, hip extensors) and was designed to improve maximal strength and explosive force production using multi-joint resistance exercises. Training variables (e.g., load, volume, progression) were adjusted throughout the intervention according to training phase. The endurance-only group continued their usual cycling training without additional strength training. Following the intervention, all participants performed endurance-only training during a high-volume training camp and a subsequent competition preparation phase.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Knee extensors strength - One repetition maximum (1RM) (kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Maximal strength (kg) for the leg extension was estimated from a five-repetition maximum (5RM) test conducted according to National Strength and Conditioning Association guidelines in two exercises (barbell squat and leg press). The corresponding 1RM values were estimated using the ExRx.net calculator.
Baseline (Week 0), Week 10, Week 14, and Week 18
Quadriceps muscles thickness (mm)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Quadriceps muscle thickness (mm) (vastus lateralis, rectus femoris, vastus medialis) assessed using B-mode ultrasound imaging.
Baseline (Week 0), Week 10, Week 14, and Week 18
Maximal voluntary isometric contraction (Nm)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Isometric maximal voluntary contraction (MVC) of the knee extensors assessed using an isokinetic dynamometer (System 3; Biodex Medical Systems, Shirley, NY, USA). Following a 5-min warm-up on a cycle ergometer at a self-selected workload and cadence, participants were seated upright in the dynamometer chair with double shoulder straps securing the upper body and were verbally encouraged to exert maximal effort. Three MVC trials were performed at a knee joint angle of 70 o (full extension = 0 deg) and the highest peak torque (Nm) was used for analysis. Each trial was separated by 1 minute of rest, and two submaximal warm-up contractions were completed before testing.
Baseline (Week 0), Week 10, Week 14, and Week 18
Isokinetic peak torque (Nm)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Isokinetic concentric peak torque of the knee extensors assessed using an isokinetic dynamometer (System 3; Biodex Medical Systems, Shirley, NY, USA). Following a 5-min warm-up on a cycle ergometer at a self-selected workload and cadence, participants were seated upright in the dynamometer chair with double shoulder straps securing the upper body and were verbally encouraged to exert maximal effort. Three maximal concentric contractions performed at a knee joint angle of 70 deg (full extension = 0 deg) and at 60 deg/s, and the highest peak torque (Nm) was used for analysis. Each trial was separated by 1 minute of rest, and two submaximal warm-up contractions were completed before testing.
Baseline (Week 0), Week 10, Week 14, and Week 18
Patellar tendon cross-sectional area (mm2)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Patellar tendon morphological changes assessed using B-mode ultrasound imaging - cross-sectional area (square millimetres).
Baseline (Week 0), Week 10, Week 14, and Week 18

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Body mass (kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Body mass (kg) assessed using standard anthropometric methods.
Baseline (Week 0), Week 10, Week 14, and Week 18
Height (cm)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Height (cm) assessed using standard anthropometric methods.
Baseline (Week 0), Week 10, Week 14, and Week 18
Body mass index (BMI) (kg/m2)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Body mass (kg) and height (m) will be used to calculate the body mass index (BMI) (kg/m2).
Baseline (Week 0), Week 10, Week 14, and Week 18
Body fat %
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
To estimate body fat (%), skinfold thickness was assessed with a GIMA Skinfold Caliper, featuring a precision of 0.2 mm, at the following sites on the right side of the body: triceps, biceps, mid-axillary, chest, subscapular, abdominal, suprailiac, thigh, and calf. The percentage of fat mass (BF%) were derived using the Jackson and Pollock equation (7-sites) and by the Siri equation. BF% was calculated from body density (BD) using SIRI equation.
Baseline (Week 0), Week 10, Week 14, and Week 18
Maximal oxygen consumption (VO2max) (L/min, ml/min/kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
For the determination of VO2max, participants initiated with a standardized warm-up at 120 W for 5-min, followed by an incremental ramp test protocol (20 W/min) on an electromagnetically braked ergometer (Lode Excalibur Sport, Lode BV). The cyclists were free to choose their pedaling cadence, and the ergometer's configuration was tailored to individual preferences and requisites. Real-time analysis of gas exchange was conducted using a spiroergometric device operating in breath-by-breath mode (MetaLyzer 3B, Cortex Biophysik), with the gas analyzer calibrated prior to each session. Heart rate was continuously monitored via a chest strap heart rate monitor (Polar H10, Polar Electro). The VO2max was determined as the highest consecutive 30-second rolling average value attained during the test.
Baseline (Week 0), Week 10, Week 14, and Week 18
Maximal aerobic power (MAP) (W, W/kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
For the determination of maximal aerobic power (MAP), participants initiated with a standardized warm-up at 120 W for 5-min, followed by an incremental ramp test protocol (20 W/min) on an electromagnetically braked ergometer (Lode Excalibur Sport, Lode BV). The cyclists were free to choose their pedaling cadence, and the ergometer's configuration was tailored to individual preferences and requisites. The maximal aerobic power (MAP) was identified as the maximum sustained power value achieved for a minimum duration of 1 second during the test. Both variables were quantified i
Baseline (Week 0), Week 10, Week 14, and Week 18
Cycling gross efficiency (%)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
Cycling gross efficiency (GE) was measured employing the MetaLyzer (MetaLyzer 3B, Cortex Biophysik) for gas exchange analysis and the Excalibur Sport bike ergometer (Lode Excalibur Sport, Lode BV). After a 5-min warm up, participants sustained a consistent cadence of 75±2 rpm while pedaling for 8-min, exerting efforts at intensities corresponding to 45% of the MAP achieved during the maximal incremental exercise test. Gross efficiency (%) was calculated for each stage using the formula: (Total work)/(Energy expended )×100. Data validity was ascertained when the respiratory exchange ratio remained stable below 1, and calculations excluded the initial minute to ensure the attainment of gas exchange plateau.
Baseline (Week 0), Week 10, Week 14, and Week 18
Sprint peak power (W, W/kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
To ensure procedural familiarity, each athlete participated in two simulation trials (i.e., spinning till sprint start and holding the sprint session for 1-2 seconds approximately) before the official 6-sec sprint commenced. Subsequently, participants exerted their utmost sprinting effort throughout the entire 6 s duration while receiving robust verbal encouragement. The Excalibur Sport bike ergometer (Lode Excalibur Sport, Lode BV) was employed for this sprint test, with the resistance (torque factor) set at 0.75 N×kg-1 of body mass and equipped with cyclist preferred pedals. The resistance was applied with a cadence threshold of 100 rpm, following a 30 s warm-up at 150 W. The sprint 1-s peak power was quantified both in absolute terms and relative to the participant's body mass (W, W/kg).
Baseline (Week 0), Week 10, Week 14, and Week 18
Sprint peak crank torque (Nm, Nm/kg)
Time Frame: Baseline (Week 0), Week 10, Week 14, and Week 18
To ensure procedural familiarity, each athlete participated in two simulation trials (i.e., spinning till sprint start and holding the sprint session for 1-2 seconds approximately) before the official 6-sec sprint commenced. Subsequently, participants exerted their utmost sprinting effort throughout the entire 6 s duration while receiving robust verbal encouragement. The Excalibur Sport bike ergometer (Lode Excalibur Sport, Lode BV) was employed for this sprint test, with the resistance (torque factor) set at 0.75 N×kg-1 of body mass and equipped with cyclist preferred pedals. The resistance was applied with a cadence threshold of 100 rpm, following a 30 s warm-up at 150 W. The sprint 1-s peak crank torque was quantified both in absolute terms and relative to the participant's body mass (Nm, Nm/kg).
Baseline (Week 0), Week 10, Week 14, and Week 18

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Lithuanian Sports University

Publications and helpful links

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General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 1, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 18, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

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Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • MNl-SVa(M)-2023-578

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant personal data will not be made publicly available due to institutional regulations, ethical considerations, and data protection requirements.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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