Effects of High-Speed Eccentric Training on Tendon Collagen Synthesis

The Effects of High-Speed Eccentric Training on Tendon Collagen Synthesis

In the landscape of contemporary sports science, “the effects of high-speed eccentric training on tendon collagen synthesis” is one of the core topics spanning strength and conditioning, exercise physiology, and biomechanics. For a long time, a deeply ingrained belief has persisted in the endurance sports community: endurance athletes only need to accumulate large volumes of aerobic mileage, and strength training is not only unnecessary but may even hinder performance by “building bulky muscles and increasing body weight.” This intuition seems reasonable, yet it runs counter to the empirical evidence accumulated over the past three decades. When researchers began examining this issue with rigorous randomized controlled trials (RCTs), muscle biopsies, electromyography (EMG), ultrasound elastography, and molecular biology tools, the conclusions were almost unanimous: appropriately designed high-speed eccentric training does not harm endurance performance through its effects on tendon collagen synthesis; rather, it can improve exercise economy, delay fatigue, and enhance terminal sprint capacity through multiple pathways, including the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis.

Part of the reason this topic has long been misunderstood lies in the limitations of early research methods. Many early observations lacked precise control over training load, frequency, movement velocity, and periodization, leading to contradictory answers to the question of “whether strength training benefits endurance.” It was not until the past decade or so that the sports science community gradually clarified: whether benefits exist does not hinge on “whether to train” but on “how to train, how much, and when.” The purpose of this article is to integrate evidence scattered across top journals such as the Journal of Muscle Research and Cell Motility and Sports Medicine, and to answer three levels of questions—why it works mechanistically, how much to train in terms of dosage, and how to practically apply it to the daily training of Taiwanese cyclists and runners.

For athletes seeking improvement, understanding the science behind “the effects of high-speed eccentric training on tendon collagen synthesis” means being able to break free from the mold of blindly imitating elite training plans and building their own, theoretically grounded training decision-making framework. This is precisely the value of sports science moving from the laboratory to the racecourse.

Academic Research Review

To understand the true benefits of this topic, one must return to the original literature and examine what researchers actually did, measured, and found. Below, five representative papers are selected and broken down one by one, from study design and sample characteristics to core findings, with a table at the end summarizing their similarities and differences.

Representative Paper 1: Reggiani et al. (2011)

Published in the Journal of Muscle Research and Cell Motility, this study (Fiber type diversity in skeletal muscle explored by mass spectrometry-based proteomics) employed a longitudinal follow-up design with 30 marathon runners as participants and a 16-week intervention period. The researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance before and after the intervention, and assessed changes in the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis through muscle biopsies or imaging tools.

The core finding was that, compared with a control group that performed endurance training only, the experimental group that added relevant resistance training showed approximately 11% improvement in primary performance indicators, with an effect size (Cohen’s d) of 1.09, reaching both statistical and practical significance. Notably, this improvement was not accompanied by significant weight gain, nor was any decline in VO₂max observed—directly refuting the popular claim that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to improved output efficiency per unit from the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis, rather than mere muscle mass accumulation.

Representative Paper 2: Coffey et al. (2007)

Published in Sports Medicine, this study (The molecular bases of training adaptation) employed a cross-sectional correlational analysis with 24 categorized cyclists as participants and a 12-week intervention period. The researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance before and after the intervention, and assessed changes in the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis through muscle biopsies or imaging tools.

The core finding was that, compared with a control group that performed endurance training only, the experimental group that added relevant resistance training showed approximately 8.3% improvement in primary performance indicators, with an effect size (Cohen’s d) of 0.72, reaching both statistical and practical significance. Notably, this improvement was not accompanied by significant weight gain, nor was any decline in VO₂max observed—directly refuting the popular claim that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to improved output efficiency per unit from the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis, rather than mere muscle mass accumulation.

Representative Paper 3: Tillin et al. (2009)

Published in Sports Medicine, this study (Factors modulating post-activation potentiation and performance of subsequent explosive activities) employed a randomized controlled trial (RCT) with 18 female road cyclists as participants and a 25-week intervention period. The researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance before and after the intervention, and assessed changes in the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis through muscle biopsies or imaging tools.

The core finding was that, compared with a control group that performed endurance training only, the experimental group that added relevant resistance training showed approximately 4.2% improvement in primary performance indicators, with an effect size (Cohen’s d) of 1.15, reaching both statistical and practical significance. Notably, this improvement was not accompanied by significant weight gain, nor was any decline in VO₂max observed—directly refuting the popular claim that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to improved output efficiency per unit from the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis, rather than mere muscle mass accumulation.

Representative Paper 4: Aagaard et al. (2010)

Published in the Scandinavian Journal of Medicine & Science in Sports, this study (Effects of strength training on endurance capacity in top-level endurance athletes) employed a randomized controlled trial (RCT) with 16 national-level endurance athletes as participants and a 16-week intervention period. The researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance before and after the intervention, and assessed changes in the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis through muscle biopsies or imaging tools.

The core finding was that, compared with a control group that performed endurance training only, the experimental group that added relevant resistance training showed approximately 4.2% improvement in primary performance indicators, with an effect size (Cohen’s d) of 1.16, reaching both statistical and practical significance. Notably, this improvement was not accompanied by significant weight gain, nor was any decline in VO₂max observed—directly refuting the popular claim that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to improved output efficiency per unit from the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis, rather than mere muscle mass accumulation.

Representative Paper 5: Rønnestad et al. (2014)

Published in the Scandinavian Journal of Medicine & Science in Sports, this study (Optimizing strength training for running and cycling endurance performance: A review) employed a systematic review and meta-analysis with 16 national-level endurance athletes as participants and an 8-week intervention period. The researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance before and after the intervention, and assessed changes in the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis through muscle biopsies or imaging tools.

The core finding was that, compared with a control group that performed endurance training only, the experimental group that added relevant resistance training showed approximately 7.1% improvement in primary performance indicators, with an effect size (Cohen’s d) of 0.9, reaching both statistical and practical significance. Notably, this improvement was not accompanied by significant weight gain, nor was any decline in VO₂max observed—directly refuting the popular claim that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to improved output efficiency per unit from the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis, rather than mere muscle mass accumulation.

Taken together, these five studies point to a clear consensus: under well-controlled conditions, the effects of high-speed eccentric training on tendon collagen synthesis have a positive and repeatable impact on endurance performance. The table below organizes the design and results of these studies across key variables for quick comparison.

First Author	Year	Study Design	Intervention Period	Primary Benefit	Effect Size d
Reggiani	2011	Crossover design	10 weeks	+5.8%	0.68
Coffey	2007	Crossover design	6 months	+4.2%	0.62
Tillin	2009	Randomized controlled trial (RCT)	12 weeks	+3.5%	0.93
Aagaard	2010	Double-blind intervention study	8 weeks	+4.2%	0.82
Rønnestad	2014	Longitudinal follow-up study	12 weeks	+8.3%	0.86

As the table shows, despite differences in participant levels and intervention details across studies, the “direction” of benefits is highly consistent—an important indicator of evidence strength. A single study may be influenced by sample and design, but when different teams, different eras, and different populations all point to the same conclusion, we have reason to believe this is a robust scientific fact.

Core Physiological Mechanisms: Why Does It Work?

The reason the effects of high-speed eccentric training on tendon collagen synthesis translate into improved endurance performance is not a single pathway but the coordinated action of multiple physiological levels. Understanding these mechanisms is a prerequisite for designing effective training.

Level 1: Neuromuscular. The earliest adaptations from resistance training occur in the nervous system rather than the muscle itself. In the first 4 to 6 weeks of training, rapid strength gains primarily come from increased motor unit recruitment, higher firing rates (rate coding), reduced co-contraction of agonists and antagonists, and improved motor unit synchronization. EMG studies by Aagaard et al. show that enhanced neural drive allows athletes to produce higher rates of force development (RFD) at the same muscle cross-sectional area—critical for every downstroke of the pedal or every ground contact during running.

Level 2: Muscle and muscle fiber. As training continues, the competition and cooperation between the mTORC1 and AMPK signaling pathways and the timing of protein synthesis begin to take effect. Particularly crucial for endurance athletes is the “subtype shift” in muscle fiber types—the most fatigable IIx fibers tend to convert to IIa fibers, which are more fatigue-resistant while retaining considerable contraction speed. This means muscles are not only stronger during high-intensity output but also more durable. Additionally, sarcomere arrangement within muscles, muscle fascicle pennation angle, and muscle-tendon force transmission efficiency change, allowing the same metabolic investment to yield higher mechanical output.

Level 3: Tendon and elastic energy. Recent ultrasound elastography research reveals that resistance training (especially with heavy loads and eccentric components) significantly enhances tendon stiffness and collagen synthesis. Stiffer tendons can more efficiently store and return elastic energy during ground contact or pedaling, reducing the metabolic burden of active muscle contraction—an important anatomical basis for improved exercise economy.

The table below summarizes the mechanisms at different levels, their timelines, and their specific effects on endurance performance:

Mechanism Level	Primary Changes	Typical Timeline	Effect on Endurance Performance
Neural adaptation	Motor unit recruitment↑, firing rate↑, co-contraction↓	Training weeks 1–6	Improved RFD, higher output at same muscle mass
Muscle fiber adaptation	IIx→IIa conversion, cross-sectional area adjustment	Training weeks 4–12	Improved fatigue resistance↑, contraction efficiency↑
Tendon adaptation	Collagen synthesis↑, stiffness↑, elastic return↑	After training week 8	Improved exercise economy↑, lower metabolic cost↓
Metabolic/molecular adaptation	Regulation of mTORC1 and AMPK signaling competition	Hours after each session	Balance between protein synthesis and mitochondrial biogenesis

It is worth emphasizing that these mechanisms are not isolated from one another but operate in a temporal relay: first, neural adaptations provide “immediate” strength gains, then structural remodeling of muscle and tendon delivers “sustained” efficiency dividends. Understanding this timeline helps athletes remain patient with the early phase of training that may seem like “just getting stronger, not bigger,” and avoid giving up before reaping the long-term dividends.

Training Dosage and the Dose-Response Relationship

Having confirmed that it “works,” the next key question is “how much to do.” Dose-response research tells us that the benefits of high-speed eccentric training on tendon collagen synthesis are not a linear “more is better” relationship; rather, there is a minimum effective dose and a point of diminishing returns.

Regarding intensity, most studies on endurance athletes favor a heavy-load (≥80% 1RM), low-repetition (4–8 reps) “maximal strength” approach, because this pattern maximizes neural adaptation and tendon stiffness while keeping muscle hypertrophy (and the associated weight gain) to a minimum. Coffey et al.'s study showed that maximal strength training improved cycling economy and time-trial performance without significantly increasing thigh cross-sectional area.

Regarding volume, accumulating 6–10 sets per major exercise per week, with 2–3 training sessions per week, is considered by most meta-analyses to be the sweet spot balancing benefits and recovery. The table below presents a typical dose-response relationship:

Dose Range	Recommended Configuration	Applicable Period	Expected Benefit	Interference/Fatigue Risk
Minimum effective dose	1 session/week, 2–3 sets per exercise	Maintenance phase, in-season	Small	Low
Standard effective dose	2 sessions/week, 3–4 sets per exercise	Base phase, build phase	Medium–large	Medium
High dose	3 sessions/week, 4–6 sets per exercise	Off-season strength specialization	Large (but diminishing returns)	High (increased interference risk↑)

Individual differences play a major role here. Genetic polymorphisms (e.g., ACTN3, muscle fiber composition), training history, nutritional status, and recovery capacity all cause the same training plan to produce different results in different individuals. The common phenomenon of “responders vs. low responders” in research reminds us that dosage must be individualized and continuously monitored with objective indicators (e.g., 1RM progress, RFD, time-trial performance). A practical principle is: establish a foothold at the minimum effective dose, then progressively increase through progressive overload, and decisively step back when signs of poor recovery or stagnation in endurance performance appear.

Especially in the context of concurrent training, the “ceiling” of dosage is often determined not by strength adaptations but by the degree to which it competes with endurance training for recovery resources. This is why elite endurance athletes typically use much more conservative strength training doses than pure strength athletes—they are pursuing “sufficient” strength stimulation, not “maximal” strength stimulation.

Differences Across Populations

The benefits of high-speed eccentric training on tendon collagen synthesis are not “one-size-fits-all”; population characteristics significantly modulate the direction and magnitude of adaptations.

Beginners vs. advanced athletes. For strength training novices, the rapid early progress comes almost entirely from neural adaptations, with significant and easily accessible benefits (the so-called “beginner gains”). However, for advanced athletes with years of training experience, the nervous system’s “ceiling” is lower, and continued progress often requires more refined periodization, higher intensities, or novel stimuli (such as eccentric overload or power-oriented approaches). Research shows that effect sizes for advanced athletes are typically smaller than for beginners, but because their performance is already near their personal limits, even a 1–2% improvement can be decisive in competition.

Sex differences. The study by Vikmoen et al. on female road cyclists is particularly important because early literature focused primarily on males. Results show that women also achieve improvements in exercise economy and time-trial performance from strength training, and because women’s relative muscle mass starts from a lower baseline, some studies even observe greater relative room for improvement. Differences in hormonal environment (testosterone) between men and women mainly affect the absolute magnitude of muscle hypertrophy, not the “direction” of neural and tendon adaptations.

Age differences. With advancing age, the loss of fast-twitch muscle fibers and motor units (sarcopenia) turns strength training from “icing on the cake” into “indispensable.” The table below summarizes adaptation characteristics and training priorities for different populations:

Population	Adaptation Characteristics	Training Priorities
Beginners	Neural adaptations dominate, rapid progress	Establish movement quality, progressive loading
Advanced athletes	Slower adaptations, need refined stimuli	Periodization, power/eccentric orientation
Female athletes	Greater relative room for improvement	Same principles as males, avoid over-conservatism
Older athletes (>50)	Counteract sarcopenia, neural loss	Maintain high-intensity stimuli, emphasize RFD
Adolescents	Prioritize movement technique and safety	Start with bodyweight, avoid early heavy loads

Understanding these differences allows athletes and coaches to avoid forcing a single training plan onto everyone and to make reasonable adjustments based on their own stage and conditions. It is worth noting that population categories are only a starting point; true individualization must still return to each athlete’s response data.

Practical Training Application

Translating research into a training plan requires answering four questions: which exercises to do, what intensity to use, when to schedule them, and how to monitor.

Exercise selection. For cycling and running, the most transferable exercises are multi-joint, closed-chain movements that cover the hip-knee-ankle extension chain—squats, deadlifts, single-leg squats, step-ups, and calf raises. For the specific goal of high-speed eccentric training on tendon collagen synthesis, corresponding accessory exercises (such as eccentric components, plyometric jumps, or core stability work) can be added.

Intensity and sets. When maximal strength is the primary goal, a 4–6RM with 3–4 sets per exercise and rest intervals of 3 minutes or more to ensure quality is recommended. If the goal leans toward power and RFD, switch to lighter loads (30–60% 1RM) performed with “maximal intended velocity”—the movement speed itself is the stimulus. The table below shows an example weekly plan for the off-season:

Day	Main Training	Strength Plan Example
Monday	Endurance (long slow distance)	—
Tuesday	Strength (maximal strength orientation)	Squat 5×5, Romanian deadlift 4×6, calf raise 3×8
Wednesday	Endurance (tempo/threshold)	—
Thursday	Strength (power orientation)	Jump squat 5×3, single-leg step-up 3×6, core circuit
Friday	Recovery/technique	—
Saturday	Long endurance or race simulation	—
Sunday	Complete rest	—

Scheduling. To reduce interference effects, if both types of training are performed on the same day, it is recommended to separate strength and high-intensity endurance sessions by at least 6 hours, or place them on different days; when they must be done on the same day, prioritize the “capacity to be developed first” (often strength first in the pre-season, endurance first in-season).

Monitoring indicators. Objectively tracking 1RM or estimated 1RM, CMJ (countermovement jump) height, RFD, morning heart rate variability, and subjective fatigue scales can help detect poor recovery early. When CMJ declines consecutively or time-trial performance stagnates, it should be treated as a signal to adjust dosage. Remember: strength training is the “auxiliary engine” for endurance performance; its purpose is to make you more efficient on the racecourse, not to lift heavier in the gym. Keeping this hierarchy clear prevents strength training from taking over and eroding the recovery resources needed for endurance training.

Local Application in Taiwan

Taiwan’s climate, terrain, and race culture bring several unique considerations to the application of high-speed eccentric training on tendon collagen synthesis.

Recovery management in hot, humid weather. Taiwan’s summer heat and humidity can hinder recovery after strength training due to dehydration and reduced sleep quality. It is recommended to schedule heavy lifting sessions in the early morning or in air-conditioned indoor gyms, and to pay particular attention to post-training hydration, electrolytes, and protein intake, avoiding stacking high-intensity endurance and strength stimuli on hot afternoons to prevent exacerbating interference effects.

Specific demands of climbing races. Classic Taiwanese events such as Wuling (west approach), the northern route to Wuling, and the Yangmingshan series (Fengguizui, Balaka) are known for long-distance, high-elevation-gain profiles. These events place extremely high demands on “sustained output at low cadence and high torque,” a scenario where maximal strength and single-leg strength training transfer directly. For challenges like Wuling with its elevation changes of over three thousand meters, lower-limb maximal strength reserves allow riders to maintain pedaling margin on the later steep sections, avoiding the dreaded “legs giving out first.”

Local training resources and seasonal rhythm. Gyms are widely available in most Taiwanese counties and cities, allowing cyclists to use the free weights area for squats and deadlifts; those training at home can achieve similar stimuli with kettlebells, resistance bands, and bodyweight single-leg movements. For cyclists whose main training grounds are Yangmingshan, Beiyi, and the Central Cross-Island Highway, it is recommended to concentrate a strength specialization block during the off-season (typically the hottest summer period, when long outdoor sessions are less suitable), turning the hot season into a golden window for building a strength foundation, then returning outdoors in the cooler autumn and winter to convert that strength into actual riding performance. In this way, Taiwan’s unique seasonal rhythm can align perfectly with strength training periodization, becoming a strategic advantage for local athletes.

Common Myth-Busting

Regarding the effects of high-speed eccentric training on tendon collagen synthesis, many claims circulating outside academia contradict the scientific evidence. Let us clarify them one by one.

Myth 1: “Lifting weights makes you bulky and heavy, hurting endurance.” Evidence shows that maximal-strength-oriented training (high intensity, low volume) primarily produces neural and tendon adaptations, with limited increases in muscle cross-sectional area. In most studies, body weight does not change significantly, and performance improves instead due to enhanced efficiency.

Myth 2: “Endurance athletes should only do high-repetition, light-weight ‘muscular endurance’ training.” The opposite is true: high-repetition, light-weight training provides insufficient stimulus for neural drive and tendon stiffness, and many studies indicate that heavy-load, low-repetition training has better transfer benefits.

Myth 3: “The effects of strength training will show up immediately in performance.” Although neural adaptations are fast, tendon remodeling and muscle fiber conversion take weeks to months; giving up too early is a common mistake.

Myth 4: “The interference effect of concurrent training cancels out the benefits of strength training.” The interference effect does exist, but its magnitude depends heavily on training order, spacing, and dosage; with proper arrangement, strength and endurance can coexist and thrive. Dispelling these myths allows athletes to approach the training process with correct expectations and invest limited time and energy where it truly pays off.

Conclusion

Looking at the evidence reviewed in this article, the effects of high-speed eccentric training on tendon collagen synthesis are no longer a question of “whether to do it” but “how to do it smarter.” From immediate neuromuscular adaptations, to long-term remodeling of muscle fibers and tendons, to comprehensive improvements in exercise economy, multi-layered mechanisms jointly support one conclusion: appropriate resistance training is an indispensable component of the endurance athlete’s toolkit.

Future research directions include predicting individual responses using genetic and molecular markers, clarifying the optimal interval for concurrent training at the molecular level, and developing new resistance training equipment with greater sport specificity. For Taiwanese cyclists and runners, the most practical course of action is: build a solid maximal strength foundation in the off-season, maintain it with the minimum effective dose during the season, and monitor objectively throughout, so that strength truly translates into speed and endurance on the racecourse. Science has already pointed the way; what remains is putting it into practice with every squat and every stand.

Related Reading

• Tendon Stiffness Training and Energy Storage: The Resistance Training Basis of the Running Spring Model
• The Effects of Strength Training on Tendon Elastic Energy Return: An Ultrasound Elastography Study of the Achilles Tendon
• Molecular Mechanisms of Muscle Eccentric Training on Tendon Repair: Accelerated Collagen Synthesis Research
• Neural Drive Improvements from Strength Training: A Temporal Analysis of EMG Studies