Strength Training For Endurance Athletes: What Are The Benefits?

Strength Training For Endurance

On the face of it, endurance and strength training are polar opposites—one involves thousands of low resistance muscle contractions, the other just a hand full of high resistance efforts.

Maybe this explains why endurance athletes are often so resistant to sacrificing their mileage for reps.

The truth is, successful training programs involve diverse training approaches. And despite the differences, strength training is one of the most effective training methods to add into your weekly schedule.

In this article we look at:

  • The science of strength training for endurance athletes
  • How it benefits endurance exercise
  • We consider which key factors improve following strength training
  • How to incorporate strength training in your weekly exercise schedule.

Benefits of Strength Training for Endurance Athletes

With strength training, research is clear… it improves key factors related to endurance and boosts exercise performance in several endurance sports. These include distance running, cycling, swimming, rowing, and cross-country skiing.

We believe strength training has this positive effect by increasing the strength of individual muscle fibers—making each contraction more forceful and increasing fatigue resistance. It also improves neuromuscular coordination, increasing the speed and efficiency of muscular contractions.

Some key benefits include:

  • Greater leg strength (Rønnestad et al., 2011; Losnegard et al., 2011; Marcinik et al., 1991; Hickson et al., 1988)
  • Maximal power (Yamamoto et al., 2010)
  • Supra-maximal (>VO2max) cycling performance (Minahan and Wood 2008)
  • Short- and long-term endurance performance (Aagaard et al., 2011; Rønnestad et al., 2011; Yamamoto et al., 2010; Sato and Mokha 2009; Paavolainen et al., 1999b; Tanaka and Swensen 1998)
  • Greater time to exhaustion in cyclists and runners (Støren et al., 2008; Minahan and Wood 2008; Marcinik et al., 1991)
  • Enhanced exercise efficiency (Louis et al., 2012; Mikkola et al., 2011; Sunde et al., 2010; Paavolainen et al., 1999b)
  • Improved blood lactate levels and the lactate threshold (Paton and Hopkins 2005; Marcinik et al., 1991).

How it improves endurance exercise

Strength training is believed to improve endurance exercise performance in several ways.

At the most basic level it leads to an increase in the size, strength and fatigue resistance of muscle fibers.

Research has also demonstrated that strength training can lead to neuromuscular improvements (Mikola et al., 2007). We also see an increase in the proportion of Type IIa muscle fibers (fast oxidative-glycolytic fibers—these have greater fatigue resistance than type IIb), while there’s a correlated reduction in the proportion of the less fatigue resistant Type IIb muscle fibers (Aagaard et al., 2011).

A further adaptation is an increase in muscle cross-sectional area.

These physiological adaptations contribute to improvements in key factors related to endurance exercise performance. 

In particular, we see improvements in exercise efficiency, the lactate threshold, and increased fatigue resistance.

Most of these improvements appear related to enhanced neuromuscular coordination, increased strength, and muscle fiber type conversions (from less to more fatigue resistant muscle fiber types).

Importantly, these adaptations occur (in endurance athletes) without affecting bodyweight (Rønnestad et al., 2010a). And, perhaps surprisingly, through an increase in the proportion of energy from aerobic energy systems (Minahan and Wood 2008). 

Improved exercise efficiency

One major benefit of strength training is improved exercise efficiency. When we talk about improved efficiency, we are refering to a reduced energy cost of exercise (kj) or lower oxygen consumption (V02).

Here, we have observed improved efficiency in runners, cyclists, swimmers and cross-country skiers.

Running efficiency

Researchers have found resistance and explosive strength training to significant improve running efficiency (Cheng et al., 2012; Mikkola et al., 2011; Taipale et al., 2010; Guglielmo et al., 2009; Yamamoto et al., 2008; Spurrs et al., 2003; Millet et al., 2002; Paavolainen et al., 1999b).

In one study researchers found that explosive strength training, comprising sprint training and jumping exercises (including bilateral countermovement, drop and hurdle jumps), significantly improved running economy by over 8% (Paavolainen et al., 1999b).

In another study, 6-weeks of Plyometric training improved both running economy and 3km running performance (Spurrs et al., 2003).

We believe these improvements are due (in part) to increased lower leg musculotendinous stiffness. This improves joint stability and enhances the energy return during the foot strike.

Researchers have also found heavy resistance training improves running economy (5-6%) (Guglielmo et al., 2009; Støren et al., 2008;).

While it’s not clear which is the best type of strength training, research shows that several types—explosive, heavy resistance and strength endurance training—all lead to significant improvements in running economy (Mikkola et al., 2011).

Research also suggests vibration training may benefit running economy (Cheng et al., 2012). However, circuit training appears to be less effective (Taipale et al., 2010).

Cycling efficiency

Strength training—particularly explosive and high resistance training—has also been found to improve cycling efficiency (Louis et al., 2012; Rønnestad, et al., 2012; Sunde et al., 2010; Paton and Hopkins 2005; Loveless et al., 2005;).

In one study, researchers found explosive strength and high-resistance interval training led to significant gains in sprint and endurance performance, among well-trained cyclists. Researchers attributed these improvements (in part) to improved exercise efficiency (Paton and Hopkins 2005).

Strength training is also beneficial for master endurance cyclists. In one study, master age group cyclist (51.5 ± 5.5 years) completed 10 sets of 10 knee extensions (70% of repetition maximum, with 3min rest between sets). They found this alleviated the age-related reductions in strength and cycling efficiency (Louis et al., 2012).

The positive effects of strength training on cycling efficiency led researchers to suggest that cyclist should include maximal strength training as part of their training routine (Sunde et al., 2010).

Swimming efficiency

There is limited research regarding strength training and highly technical sports like swimming.

Some research has failed to find improvements in swim stroke dynamics following resistance training (Tannaka et al., 1993)—demonstrating the importance of specificity in technical sports like swimming. However, in other research dry-land strength training improved stroke length in national level swimmers (Girold et al., 2012).

They have also found resisted sprint swim training improved stroke technique in swimming (Girold et al., 2006). Arms only swim training (comprising 20% of weekly training volume)—a training approach that increases the work by arms at a given speed—also appears to benefit swimming movement economy (Konstantaki et al., 2008).

Cross-country skiing

Strength training has also proved useful for cross-country skiers. Here heavy resistance training improved exercise efficiency/exercise economy in a group of cross-country skiers (Hoff et al., 2002 & 1999).

Strength training and the lactate threshold

Early research highlighted that strength training may be an effective way to increase the lactate threshold (Tanaka and Swensen 1998; Marcinik et al, 1991).

Researchers have demonstrated that a combination of explosive and high resistance interval training improves exercise efficiency and the anaerobic threshold in a group of well-trained cyclists (Paton and Hopkins 2005).

It’s thought that the improvements in the lactate threshold occur because of a combination of improved exercise efficiency, enhanced muscle fiber-recruitment and an increase in the proportion of energy from aerobic metabolism.

1. Enhanced exercise efficiency:

When we see improvements in exercise efficiency, we often see improvements across a range of speeds/intensities—from low to near maximal intensities.

In this way, any improvement in exercise efficiency will increase the speed or power at the lactate threshold. It also increases the speed or power at VO2 max.

2. Increased strength of muscles and muscle fibers:

Another reason for the improvement in the lactate threshold relates to the improved strength of muscles, individual muscle fibers, and the ability to recruit a greater proportion of muscle fibers.

Why is that?… By increasing maximum strength we increase our strength reserve—the difference between maximum strength and the strength required to exercise at lower intensities.

This makes work easier at lower intensities. And by recruiting a greater proportion of muscle fibers, we reduce the overall work performed by individual muscle fibers at any given intensity.

Taken together, this allows greater work to be completed at lactate threshold intensity. It also increases fatigue resistance.

3. Greater proportion of energy from aerobic metabolism:

As mentioned, strength training can increase the proportion of energy from aerobic metabolism. When this happens, you shift the point where metabolism transition from mainly aerobic to increased anaerobic metabolism. This pushes up the lactate threshold speed, or intensity.

Improved endurance exercise performance

So how does strength training impact endurance exercise performance?… Several studies have observed improved endurance exercise performance, and fatigue resistance, following strength training (Aagaard et al., 2011; Mikkola et al., 2011; Rønnestad et al., 2010a & 2011; Yamamoto et al., 2010; Sato and Mokha 2009; Paton and Hopkins, 2005; Hoff et al., 2002;).

First, let’s look at strength training and cycling performance.

Endurance cycling performance

They have demonstrated strength training to boost endurance cycling in both long term and short-term events. Supra-maximal (above VO2max) intensity cycling also improves following strength training.

Research looking at the effects of combined endurance and strength/resistance training on time trial performance in young top-level cyclists, observed significant improvements in short (5min) and long (45min) time trial performance (Aagaard et al., 2011). These improvements were accompanied by an increase in type IIa muscle fibers and a decrease in type IIx fibers.

Research in well-trained cyclists found that heavy resistance exercise can improve performance in a 5minute all-out effort, following a 185 minute cycle (Rønnestad et al., 2011).

We can also use strength training during a competition period, to maintain and enhance gains in strength and performance (Rønnestad et al., 2010).

Strength training has also been found to improve supramaximal cycling performance (Minahan and Wood 2008). Interestingly, researchers found that the increase in time to exhaustion (at 120% VO2 peak) was associated with increased aerobic energy contribution rather than increased anaerobic capacity.

Endurance running performance

A range of different resistance training approaches and intensities have been effective at enhancing endurance running performance:

1) Heavy resistance training improves the time to exhaustion at the maximal aerobic running speed (vVO2max) in well trained long-distance runners (Støren et al., 2008);

2) Explosive strength training was found to improve 5km race performance (Paavolainen et al., 1999b);

3) Running specific strength training helps to minimize reductions in stride length, that occur when fatigue sets in. (Esteve-Lanao et al., 2008); and

4) Core strength training has been shown to improve 5000m run times, after just six weeks of training (Sato and Mokha 2009).

What’s the best type of strength training for endurance athletes?

To date, there have been many studies highlighting the benefits of explosive strength training (Saunders et al., 2006; Paton and Hopkins 2005; Spurrs et al., 2003; Paavolainen et al., 1999b), heavy resistance training (Louis et al., 2012; Aagaard et al., 2011; Rønnestad et al., 2011 & 2010a; Mikkola et al., 2011; Losnegard et al., 2011; Sunde et al., 2010; Guglielmo et al., 2009; Minahan and Wood, 2008; Støren et al., 2008; Loveless et al., 2005; Hoff et al., 2002 & 1999); vibration plate training (Cheng et al., 2012) and core strength exercises (Sato and Mokha 2009) for improving endurance performance.

While we know strength training is beneficial, it’s less clear which method provides the greatest endurance benefit.

To highlight this… one study found that explosive strength training improved running economy to a greater extent than dynamic weight training (Berryman et al., 2010;), while another found heavy weight training to be better than explosive strength training (Guglielmo et al., 2009).

What we can say is strength training is beneficial.

It is likely that a combination of heavy weight and explosive/plyometric training is the best approach to improve endurance performance.

That said, it’s important to recognize there’s a greater risk of injury with plyometric training. So anyone without an adequate strength training background should start with a general strength training program.

It’s also important to remember that there are several different types of strength and each contributes to endurance performance.

There are also different types of muscle contractions—the importance of each varies depending on the sport. For example, running involves primarily eccentric and concentric contractions; whereas cycling mainly involves concentric contractions. Highlighting, why it’s important to use sport specific exercises when doing any cross-training.

Training experience is important

It’s important to consider the strength training background of an endurance athlete before beginning any weight training programme.

Why is that?… Research in rowers found that less experienced rowers experienced greater gains through the use of high repetitions than experienced rowers (Ebben et al., 2004), indicating that endurance athletes should gradually increase resistance training intensity based on their experience level.

Endurance athletes that are new to weight training may want to use light/moderate weights and employ a high repetition approach. Those with a greater level of weight training experience can place a greater emphasis on heavier weights and fewer repetitions.

Research also indicates that it may not be necessary to perform the repetitions to failure (Izquierdo-Gabarren et al., 2010). This is an important point, as it will reduce the risk of strength training compromising endurance workouts. It will also reduce the risk of over-training.

What’s the optimum number of repetitions, sets and training frequency?

1. Optimum number of repetitions

The traditional approach is to complete sets of approximately 15-20 repetitions using a weight that is approximately 60-65% of 1 repetition maximum (Martin and Coe, 1997). However, current research looking at the benefits of strength training on endurance performance has used heavier weights with a lower rep range (4-10reps at 70-85% 1RM).

Athletes who are new to strength training should start with lighter weights and higher repetition numbers (e.g. 15-20 reps). The intensity (% of RM) can then be gradually increased.

For example, Weeks 1-4 = 15-20RM, Weeks 5-8 = 12-15RM, Weeks 9-12 = 10-12RM, Weeks 13-16 = 8-10RM. This is necessary, because it allows muscles and tendons to strengthen and adapt in a progressive manner.

2. Optimum number of sets

Most research has used 3-10 sets.

If you are using more than one different exercise, then 3 sets per exercise works well. For example: 3 sets of half squat, 3 sets of leg extension, and 3 sets of leg curl, 3 sets of calf raises.

3. Strength training frequency

All the current research has employed an exercise frequency of 2-3 sessions per week.

For most athletes, two sessions per week will be adequate, especially if you are also including high-intensity interval training. In fact, many endurance athletes will gain significant benefits from just 1 weekly strength session.

If performing strength exercise more than once per week, then consider changing the intensity on specific days. For example, on day 1 train at an intensity of 5-6RM, on the second strength day use an intensity of 8-10RM, or 12-15RM—this periodized approach often produces bigger gains than conventional training approaches.

Summary of strength training approaches used in research

The table below summarizes the training approaches (repetitions, sets, repetition maximum—RM, and training frequency) applied during research looking at strength training for endurance.

ResearchersTraining ProgrammeFrequencySubjects
Louis et al., (2012)10 x 10 knee extensions (70% 1RM)3 x WeeklyCyclists
Rønnestad et al., (2012)4 lower body exercises, 3 × 4-10 RM2 x WeeklyCyclists
Rønnestad et al., (2011)4 lower body exercises, 3 × 4-10 RM2 x WeeklyCyclists
Rønnestad et al., (2010a)4 lower body exercises, 3 × 4-10 RM2 x WeeklyCyclists
Rønnestad et al., (2010)4 lower body exercises, 3 × 4-10 RM2 x WeeklyCyclists
Sunde et al., (2010)4 x 4 RM Half Squats3 x WeeklyCyclists
Minahan and Wood (2008)4 x 5 reps at 85% 1RM3 x WeeklyCyclists
Støren et al., (2008)4 x 4 RM3 x WeeklyRunners
Saunders et al., (2006)30 minute plyometric session3 x WeeklyRunners
Paavolainen et al., (1999)15-90 minutes of Explosive Training32% of Training VolumeRunners
Hoff et al., (2002)3 x 6 RM (85% of 1RM)3 x WeeklyXC Skiing


  • Strength training is been proven to benefit several endurance sports including cycling, running, swimming, rowing, and cross-country skiing.
  • Research has found concurrent strength and endurance training increases the size and fatigue resistance of muscle-fibers, and increases the proportion of type IIa fibers, while decreasing the proportion of the less fatigue resistant type IIb fibers.
  • It significantly increases exercise efficiency, the speed or power output at the lactate threshold, fatigue resistance and endurance exercise performance.
  • There are four types of strength training that improve exercise performance: heavy resistance training, explosive strength training (plyometrics), core strength training and vibration plate training. Of the four types, heavy resistance training and plyometric training appear to be the most effective.
  • Current research suggests exercise using weights that can be lifted for 4-10repetitions (approximately 70-85% of 1 repetition maximum). Each workout should include 3-10 sets and be performed 2-3 times per week. However, for most endurance athletes, 1-2weekly sessions will be sufficient.
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