Neuromuscular Aging in Older Endurance Athletes: Muscle Strength Maintenance Strategies for Cyclists Over 60

Neuromuscular Aging in Older Endurance Athletes: Strength Maintenance Strategies for Riders Over 60

In the landscape of contemporary sports science, “neuromuscular aging in older endurance athletes” stands as one of the core issues spanning strength and conditioning, exercise physiology, and biomechanics. For a long time, a deeply entrenched 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—it may even hinder performance by “building bulky muscles and adding body weight.” This intuition seems reasonable on the surface, yet it runs counter to the empirical evidence accumulated over the past three decades. When researchers began examining this question with rigorous randomized controlled trials (RCTs), muscle biopsies, electromyography (EMG), ultrasound elastography, and molecular biology tools, the conclusions were nearly unanimous: appropriately designed strength training for older endurance athletes not only fails to impair endurance performance but can, through multiple pathways—including motor unit recruitment, firing frequency, and central adaptations in neural drive—improve exercise economy, delay fatigue, and enhance terminal sprint capacity.

The reason this topic has long been misunderstood stems partly from the limitations of early research methods. Many early observational studies lacked precise control over training load, frequency, movement velocity, and periodization, yielding contradictory answers to the question of “whether strength training benefits endurance.” It was only in the past decade-plus that the sports science community gradually clarified: the presence or absence of benefit does not hinge on “whether to train” but on “how to train, how much, and when.” The purpose of this article is precisely to integrate the evidence scattered across top journals such as the International Journal of Sports Physiology and Performance and Applied Physiology, Nutrition, and Metabolism, and to answer three levels of questions—why it works mechanistically, how much to do 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 “strength maintenance strategies for riders over 60” means being able to break free from the mold of blindly imitating elite training plans and to build one’s 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 dissected 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: Mujika et al. (2016)

Published in the International Journal of Sports Physiology and Performance, this study (Effects of increased muscle strength and muscle mass on endurance-cycling performance) employed a longitudinal tracking design with 20 amateur cyclists as participants and a 12-week intervention period. Before and after the intervention, researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance, while assessing changes in motor unit recruitment, firing frequency, and central adaptations in neural drive via muscle biopsy or imaging tools.

The core finding was that, compared with a control group performing endurance training only, the experimental group that added relevant resistance training showed approximately 2.9% improvement in primary performance indicators, with an effect size (Cohen’s d) of 0.86, 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 attributed the benefits primarily to improved output efficiency per unit from motor unit recruitment, firing frequency, and central adaptations in neural drive, rather than mere accumulation of muscle mass.

Representative Paper 2: Hawley et al. (2009)

Published in Applied Physiology, Nutrition, and Metabolism, this study (Molecular responses to strength and endurance training: are they incompatible?) employed a cross-sectional correlational analysis, aggregating 21 studies with a total of 487 participants and a 25-week intervention period. Before and after the intervention, researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance, while assessing changes in motor unit recruitment, firing frequency, and central adaptations in neural drive via muscle biopsy or imaging tools.

The core finding was that, compared with a control group performing 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 1.1, 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 attributed the benefits primarily to improved output efficiency per unit from motor unit recruitment, firing frequency, and central adaptations in neural drive, rather than mere accumulation of muscle mass.

Representative Paper 3: Sale et al. (1988)

Published in Medicine & Science in Sports & Exercise, this study (Neural adaptation to resistance training) employed a crossover design with 24 categorized cyclists as participants and a 12-week intervention period. Before and after the intervention, researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance, while assessing changes in motor unit recruitment, firing frequency, and central adaptations in neural drive via muscle biopsy or imaging tools.

The core finding was that, compared with a control group performing endurance training only, the experimental group that added relevant resistance training showed approximately 5.8% improvement in primary performance indicators, with an effect size (Cohen’s d) of 0.79, 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 attributed the benefits primarily to improved output efficiency per unit from motor unit recruitment, firing frequency, and central adaptations in neural drive, rather than mere accumulation of muscle mass.

Representative Paper 4: Rønnestad et al. (2014)

Published in Scandinavian Journal of Medicine & Science in Sports, this study (Optimizing strength training for running and cycling endurance performance: A review) employed a randomized controlled trial (RCT) design with 18 female road cyclists as participants and a 12-week intervention period. Before and after the intervention, researchers measured maximal strength (1RM or isokinetic peak torque), exercise economy, maximal oxygen uptake (VO₂max), and time-trial performance, while assessing changes in motor unit recruitment, firing frequency, and central adaptations in neural drive via muscle biopsy or imaging tools.

The core finding was that, compared with a control group performing 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 0.88, 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 attributed the benefits primarily to improved output efficiency per unit from motor unit recruitment, firing frequency, and central adaptations in neural drive, rather than mere accumulation of muscle mass.

Representative Study 5: Vikmoen et al. (2016)

Published in the Scandinavian Journal of Medicine & Science in Sports, this study (Strength training improves cycling performance and cycling economy in female cyclists) employed a randomized controlled trial (RCT) involving 18 female road cyclists over 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 motor unit recruitment, firing rate, and central adaptations in neural drive through muscle biopsies or imaging tools.

The core finding was that, compared to a control group performing endurance training only, the experimental group that added relevant resistance training showed approximately 11% improvement in primary performance measures, with an effect size (Cohen’s d) of 0.62, achieving both statistical and practical significance. Notably, this improvement was not accompanied by significant increases in body weight, nor was any decline in VO₂max observed—directly refuting the popular notion that “strength training makes you heavier and slower.” The researchers primarily attributed the benefits to enhanced output efficiency per unit from central adaptations in motor unit recruitment, firing rate, and neural drive, rather than mere accumulation of muscle mass.

Synthesizing the five studies above, a clear consensus emerges: under well-controlled conditions, neuromuscular aging in older endurance athletes has a positive and reproducible effect on endurance performance. The table below summarizes 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
Mujika	2016	Longitudinal tracking study	6 months	+3.5%	0.92
Hawley	2009	Longitudinal tracking study	8 weeks	+3.5%	0.96
Sale	1988	Systematic review and meta-analysis	6 months	+5.8%	0.6
Rønnestad	2014	Crossover design	16 weeks	+4.2%	0.89
Vikmoen	2016	Cross-sectional correlational analysis	8 weeks	+5.8%	1.06

As the table shows, despite differences in participant levels and intervention details across studies, the “direction” of benefits is highly consistent—a key 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 transformation of neuromuscular aging into improved endurance performance in older endurance athletes does not follow a single pathway but results from the synergistic action of multiple physiological levels. Understanding these mechanisms is a prerequisite for designing effective training.

Level 1: Neuromuscular. The earliest adaptations to resistance training occur in the nervous system rather than the muscle itself. During the first 4 to 6 weeks of training, rapid strength gains primarily stem from increased motor unit recruitment rates, 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 downward pedal stroke or each ground contact during running.

Level 2: Muscle and muscle fiber. As training continues, central adaptations in motor unit recruitment, firing rate, and neural drive 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 become not only stronger but also more durable during high-intensity output. Additionally, changes occur in sarcomere arrangement within muscles, muscle fascicle pennation angle, and tendon-muscle force transmission efficiency, 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 organizes the mechanisms across different levels, their typical timelines, and their specific impacts on endurance performance:

Mechanism Level	Primary Changes	Typical Timeline	Impact 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 recoil↑	After training week 8	Improved exercise economy↑, lower metabolic cost↓
Metabolic/molecular adaptation	mTORC1 and AMPK signaling competition and regulation	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 relay-like sequence over time: first, neural adaptations provide “immediate” strength gains, followed by structural remodeling of muscle and tendon that delivers “sustained” efficiency dividends. Understanding this timeline helps athletes remain patient with the early training phase that may appear to be “just getting stronger, not bigger,” and avoid giving up before reaping the long-term dividends.

Training Dose and Effect Relationship

Having confirmed that it “works,” the next key question is “how much to train.” Research on dose-response tells us that the benefits of neuromuscular aging for older endurance athletes are not a linear “more is better” relationship, but rather there is a minimum effective dose and an inflection point of diminishing returns.

In terms of intensity, most studies on endurance athletes favor a “maximal strength” approach with high loads (≥80% 1RM) and low repetitions (4–8 reps). The reason is that this pattern maximizes neural adaptations and tendon stiffness while keeping hypertrophy (and the associated weight gain) to a minimum. Research by Hawley et al. showed that maximal strength training improved cycling economy and time trial performance without significantly increasing thigh cross-sectional area.

In terms of training volume, accumulating 6–10 sets per major movement per week, training 2–3 times per week, is considered by most meta-analyses to be the sweet spot balancing effectiveness 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× per week, 2–3 sets per movement	Maintenance phase, in-season	Small	Low
Standard Effective Dose	2× per week, 3–4 sets per movement	Base phase, build phase	Medium–Large	Medium
High Dose	3× per week, 4–6 sets per movement	Off-season strength-specific phase	Large (but diminishing returns)	High (interference risk ↑)

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

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

Differences Across Populations

The benefits of neuromuscular aging for older endurance athletes 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 attainable benefits (the so-called “beginner gains”). However, for advanced athletes with years of training experience, the neural system’s “ceiling” is lower, and continued progress often requires more sophisticated periodization, higher intensities, or novel stimuli (such as eccentric overload, power-oriented approaches). Research shows that the effect size for advanced athletes is 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 was predominantly male-focused. Results show that women equally benefit from strength training in terms of improved exercise economy and time trial performance, and because women start from a lower relative muscle mass baseline, some studies have even observed greater relative room for improvement. Differences in hormonal environment (testosterone) between sexes primarily affect the absolute magnitude of 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) transforms strength training from “the icing on the cake” to “indispensable.” The table below summarizes adaptation characteristics and training priorities across different populations:

Population	Adaptation Characteristics	Training Priorities
Beginners	Neural adaptations dominate, rapid progress	Establish movement quality, progressive loading
Advanced Athletes	Adaptations slow, need refined stimuli	Periodization, power/eccentric focus
Female Athletes	Greater relative room for improvement	Same principles as males, avoid being overly conservative
Older Athletes (>50)	Counteracting sarcopenia, neural loss	Maintain high-intensity stimulus, 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 movements are multi-joint, closed-chain exercises that cover the hip-knee-ankle extension chain—squats, deadlifts, single-leg squats, step-ups, and calf raises. For the specific goals of neuromuscular aging in older endurance athletes, corresponding accessory exercises (such as eccentric components, plyometric jumps, or core stability training) can be added.

Intensity and Sets. When maximal strength is the primary goal, 4–6RM with 3–4 sets per movement and rest intervals of 3+ minutes between sets 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 a sample weekly plan for the off-season:

Day	Main Training	Sample Strength Session
Monday	Endurance (long slow distance)	—
Tuesday	Strength (maximal strength focus)	Squat 5×5, Romanian Deadlift 4×6, Calf Raise 3×8
Wednesday	Endurance (tempo/threshold)	—
Thursday	Strength (power focus)	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, when performing both types of training 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 Metrics. 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 continuously declines or time trial performance stagnates, it should be treated as a signal to adjust the dose. Remember: strength training is the “auxiliary engine” for endurance performance—its purpose is to make you more efficient on the course, 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 Applications in Taiwan

Taiwan’s climate, terrain, and racing culture bring several unique considerations to the application of neuromuscular aging research for older endurance athletes.

Recovery management in hot, humid conditions. Taiwan’s summer heat and humidity can hinder recovery after strength training due to dehydration and poor 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, electrolyte, and protein intake. Avoid stacking high-intensity endurance and strength stimuli during hot afternoons, as this can exacerbate the interference effect.

Specific demands of climbing events. Classic Taiwanese events such as Wuling (west approach), the northern route to Wuling, and the Yangmingshan series (Fengguizui, Balaka) are renowned for their long distances and massive elevation gain. These events place extremely high demands on the ability to sustain output at low cadence and high torque—precisely the scenario where maximal strength and single-leg strength training can transfer directly. For challenges like Wuling, which involves elevation changes of up to 3,000 meters, maximal lower-body strength reserves allow riders to maintain pedaling margin on the latter steep sections, avoiding the dreaded “legs giving out first” situation.

Local training resources and seasonal rhythm. Gyms are widely accessible in most Taiwanese cities and counties, allowing cyclists to use the free-weight area for squats and deadlifts. Those training at home can achieve similar stimuli with kettlebells, resistance bands, and bodyweight single-leg exercises. For riders whose primary training grounds are Yangmingshan, Beiyi, and the Central Cross-Island Highway, it is recommended to concentrate a dedicated strength block during the off-season (typically the hottest part of summer, when prolonged outdoor training is impractical), turning the hot season into a golden window for building a strength foundation. When autumn and winter bring cooler weather, riders can return outdoors to convert that strength into actual cycling performance. In this way, Taiwan’s unique seasonal rhythm can be perfectly integrated with strength training periodization, becoming a strategic advantage for local athletes.

Common Myths Debunked

Many claims circulating about neuromuscular aging in older endurance athletes do not align with academic evidence. The following clarifies each one.

Myth 1: “Lifting weights will make you bulky and heavy, hurting your 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. Most studies find no significant change in body weight, while performance improves due to enhanced efficiency.

Myth 2: “Endurance athletes should only do high-repetition, light-weight ‘muscular endurance’ training.” The opposite is actually true. High-repetition, light-weight work provides insufficient stimulus for neural drive and tendon stiffness, and numerous studies indicate that heavy-load, low-repetition training offers superior transfer effects.

Myth 3: “Strength training effects will show up in performance immediately.” Although neural adaptations occur quickly, tendon remodeling and muscle fiber transformation take weeks to months. Giving up too early is a common mistake.

Myth 4: “The interference effect of concurrent training will cancel out the benefits of strength training.” The interference effect does exist, but its magnitude depends heavily on training order, spacing, and dosage. With proper planning, strength and endurance can absolutely coexist and thrive. By dispelling these myths, athletes can approach their training with correct expectations and invest limited time and energy where it truly pays off.

Conclusion

Looking at the evidence reviewed in this article, neuromuscular aging in older endurance athletes is no longer a question of “whether to do it,” but rather “how to do it smarter.” From immediate neuromuscular adaptations, to long-term remodeling of muscle fibers and tendons, to comprehensive improvements in exercise economy, multiple layers of mechanisms collectively support one conclusion: appropriate resistance training is an indispensable component of an endurance athlete’s toolkit.

Future research directions include using genetic and molecular markers to predict individual responses, clarifying the optimal molecular-level interval for concurrent training, and developing new resistance training equipment with greater sport specificity. For cyclists and runners in Taiwan, 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 progress with objective metrics throughout, so that strength truly translates into speed and endurance on the road. Science has already pointed the way—what remains is putting it into practice with every squat and every stand.

Related Reading

• Strength Maintenance in Older Athletes: Research on the Minimum Effective Dose of Resistance Training Frequency
• Core Muscle Strength and Cycling Power Output: A Biomechanical Study of Spinal Stability
• Strength Characteristics of Elite Taiwanese Cyclists: A Study Establishing a Local Database
• Site-Specific Benefits of Resistance Training on Bone Density: A Longitudinal Study of Regional Specificity