Strength Training For Endurance

Strength/resistance training has been demonstrated to have a positive impact on a number of endurance sports including running, cycling, swimming, rowing, and cross country skiing. It is believed to work primarily by increasing the strength of individual muscle fibres (making each contraction more forceful), enhancing fatigue resistance, improving neuro-muscular co-ordination and hence the economy/efficiency of movement.

Research is clear that strength training has a positive impact on endurance exercise performance, and has demonstrated that it improves: leg strength (Rønnestad et al., 2011; Losnegard et al., 2011; Marcinik et al., 1991; Hickson et al., 1988;), maximal power (Yamamoto et al., 2010), the velocity at VO2max (Taipale 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); improves time to exhaustion in cyclists and runners (Støren et al., 2008; Minahan and Wood 2008; Marcinik et al., 1991), improves exercise efficiency (Louis et al., 2012; Mikkola et al., 2011; Sunde et al., 2010; Paavolainen et al., 1999b;) and leads to improvements in blood lactate levels and the lactate threshold(Paton and Hopkins 2005; Marcinik et al., 1991).

Strength Training and Exercise Efficiency

Resistance and or explosive strength training has been shown to lead to significant improvements in running economy (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, consisting of sprint training and jumping exercises (including bilateral countermovement, drop and hurdle jumps), significantly improved running economy by more than 8% (Paavolainen et al., 1999b). In a later study 6-weeks of Plyometric training improved both running economy and 3km running performance (Spurrs et al., 2003). The improvements in running economy, following plyometric training, are believed to be due in part to increased lower leg musculotendinous stiffness which may improve joint stability and enhance the energy return during the footstrike.

Heavy resistance training has also been found to significantly increase running economy (5-6%) (Guglielmo et al., 2009; Støren et al., 2008;). The optimum level of resistance training is not clear, however, research suggests that explosive, heavy resistance and endurance resistance training all lead to significant improvements in running economy (Mikkola et al., 2011), however circuit training appears to be less effective at improving running economy (Taipale et al., 2010). Recent research also suggests that whole body vibration training can lead to significant improvements in running economy (Cheng et al., 2012).

Resistance training – particularly explosive training and high resistance training – has also been found to be beneficial for improving cycling economy (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 that the addition of explosive training and high-resistance interval training to the training programs of well-trained cyclists led to major gains in sprint and endurance performance, which was partly attributed to improved exercise efficiency (Paton and Hopkins 2005). Strength training has also proved to be beneficial to master endurance cyclists (51.5 ± 5.5 years), where the inclusion of 10 sets of 10 knee extensions ( 70% RM with 3min rest), was found to alleviate the age related reductions in both strength and efficiency (Louis et al., 2012). The positive effects of resistance training on cycling economy have led researchers to suggest that cyclist include maximal strength training as part of their training routine (Sunde et al., 2010).

Resistance training has also been found to lead to improvements in work/exercise economy in cross country skiing (Hoff et al., 2002 & 1999). There is limited research with regard to strength training and highly technical sports like swimming. Early research failed to find improvements in swim stroke dynamics following a resistance training programme (Tannaka et al., 1993) demonstrating the importance of specificity of resistance training in technical sports like swimming. However, recent research has found that dry-land strength training led to improvements in stroke length amongst national level swimmers (Girold et al., 2012). Resisted sprint swim training has also been found to be beneficial for improved stroke technique in swimming (Girold et al., 2006). Arms only swim training (consisting of 20% of weekly training volume) – a training technique that increases the work done by arms at a given speed when swimming – appears to be beneficial for swimming movement economy (Konstantaki et al., 2008).

Strength Training and the Lactate Threshold

Early research highlighted that strength training may be an effective means of enhancing the lactate threshold (Tanaka and Swensen 1998; Marcinik et al, 1991;). The combination of explosive and high resistance interval training has been shown to enhance exercise efficiency and the anaerobic threshold in a group of well-trained cyclists (Paton and Hopkins 2005). It is believed that the improvements in the lactate/anaerobic threshold occur due to a combination of improved exercise efficiency/economy and increased muscle fibre-recruitment during exercise which reduces the overall work performed by individual muscle fibres at a given intensity and allows greater work to be performed before reaching the point of the lactate threshold.

Strength Training and Endurance Exercise Performance

A number of studies have found improved endurance performance and fatigue resistance following resistance 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;). Research looking at the effects of combined endurance and strength/resistance training on time trial performance in young top-level cyclists found significant improvements in both short (5min) and long (45min) time trial performance (Aagaard et al., 2011). The improvements were accompanied by an increase in type IIa muscle fibres and a decrease in type IIx fibres. Research in well-trained cyclists has also found that heavy resistance training improved performance in a 5minute all-out effort, following a 185 minute cycle (Rønnestad et al., 2011). Strength training can also be used in a competition period in order to maintain and enhance gains in strength and performance from a previous preparatory period of training. (Rønnestad et al., 2010).

A range of different resistance training methods and intensities have been found to be effective at enhancing endurance running performance: 1) Heavy resistance training has been shown to improve the time to exhaustion at the maximal aerobic running speed in well trained long distance runners (Støren et al., 2008); 2) Explosive strength training improved 5km race performance (Paavolainen et al., 1999b); 3) Running specific strength training has been found to help minimize the reductions in stride length that can occur as 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).

Strength training has also been found to improve supramaximal cycling performance (Minahan and Wood 2008). Interestingly this study found that the increase in time to exhaustion at 120% VO2peak was associated with increased aerobic energy contribution rather than increased anaerobic capacity.

How does strength training improve endurance performance?

Strength training has been shown to increase the size, strength and fatigue resistance of muscle fibres. Research has shown that strength training can lead to neuromuscular improvements (Mikola et al., 2007), increase the proportion of Type IIa muscle fibres (fast oxidative-glycolytic fibers -these have greater fatigue resistance than type IIb) whilst decreasing the proportion of Type IIb muscle fibres (Aagaard et al., 2011), increase muscle cross sectional area without increases in bodyweight (Rønnestad et al., 2010a), and appears to increase the proportion of energy from aerobic energy systems (Minahan and Wood 2008). When strength training is added to an endurance programme it appears to enhance exercise efficiency, the speed, or power output, at which the lactate threshold occurs, and fatigue resistance mainly through neuromuscular improvements and muscle fibre type transitions (from less fatigue resistant to more fatigue resistant muscle fibre types). Importantly it appears to achieve this through increasing the aerobic energy contribution (Minahan and Wood 2008) and without increasing body-mass (Rønnestad et al., 2010a).

What is the best strength/resistance training method for improved exercise performance?

To date there have been numerous 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 training (Sato and Mokha 2009) for improving endurance performance. However, it is not clear at this point which method provides the greatest improvement or benefit to endurance athletes – one study found that explosive strength training improved running economy to a greater extent than dynamic weight training (Berryman et al., 2010;), whilst another found that heavy weight training appeared to be better at improving running economy than explosive strength training (Guglielmo et al., 2009).

It is likely that a combination of heavy weight training and explosive/plyometric training may provide the best approach to enhance endurance performance. However, it is important to remember that there is a greater risk of injury with plyometric training and it should not be undertaken by anyone without an adequate strength/resistance training background. It is also important to consider the strength training background of an endurance athlete before undertaking any heavy weight training programme. Research in rowers found that less experienced rowers experienced greater gains through the use of high repetition numbers than experienced rowers (Ebben et al., 2004), suggesting that endurance athletes should aim to gradually increase the resistance training intensity from a moderate weight-high repetition approach, for those with less experience, to a greater emphasis on heavy-weight less repetitions in the more experienced. Research also suggests that it may not be necessary for athletes to perform the repetitions to failure (Izquierdo-Gabarren et al., 2010) and therefore you should use a weight that allows you to achieve the target rep range across all sets.

What is the optimum number of repetitions, sets and frequency of strength training for endurance performance?

Repetitions – traditionally, it has always been viewed that the best approach for endurance athletes is to complete sets of approximately 15-20 repetitions with a weight that is approximately 60-65% of 1 repetition maximum (Martin and Coe, 1997). However, most current research looking at the benefits of strength training on endurance performance has utilised heavier weights with a lower repetition range (4-10reps at approximately 70-85% 1RM). Athletes who are new to strength training should start with lighter weights and utilise higher repetition numbers (e.g. 15-20 reps) and gradually increase the intensity (% of RM) e.g. Weeks 1-4 = 15-20RM, Weeks 5-8 = 12-15RM, Weeks 9-12 = 10-12RM, Weeks 13-16 = 8-10RM. This is important as it allows muscles and tendons to strengthen and adapt to the weight in a progressive manner.

Sets – most of the research has used 3-10 sets during their research. If you are performing more than one exercise during the workout then 3 sets per exercise tends to work well e.g. 3 sets of half squat, 3 sets of leg extension, and 3 sets of leg curl.

Training frequency – All the current research has used a training frequency of 2-3 times per week. Two times per week is likely to be adequate particularly if you are also including high intensity interval training. Consider varying the intensity on different days e.g. strength training day 1 train at an intensity of 5-6RM, strength training day 2 train at an intensity of 8-10RM – this periodized approach has been shown to produce greater gains than the traditional approach of always training within the same repetition range.

Summary of Selective Strength Research Programmes

Researchers Training Programme Frequency Subjects
Louis et al., (2012) 10 x 10 knee extensions (70% 1RM) 3 x Weekly Cyclists
Rønnestad et al., (2012) 4 lower body exercises, 3 × 4-10 RM 2 x Weekly Cyclists
Rønnestad et al., (2011) 4 lower body exercises, 3 × 4-10 RM 2 x Weekly Cyclists
Rønnestad et al., (2010a) 4 lower body exercises, 3 × 4-10 RM 2 x Weekly Cyclists
Rønnestad et al., (2010) 4 lower body exercises, 3 × 4-10 RM 2 x Weekly Cyclists
Sunde et al., (2010) 4 x 4 RM Half Squats 3 x Weekly Cyclists
Minahan and Wood (2008) 4 x 5 reps at 85% 1RM 3 x Weekly Cyclists
Støren et al., (2008) 4 x 4 RM 3 x Weekly Runners
Saunders et al., (2006) 30 minute plyometric session 3 x Weekly Runners
Paavolainen et al., (1999) 15-90 minutes of Explosive Training 32% of Training Volume Runners
Hoff et al., (2002) 3 x 6 RM (85% of 1RM) 3 x Weekly XC Skiing

Summary of Strength Training for Endurance

  • Strength training has been shown to be a beneficial training technique for a number of endurance sports including cycling, running, swimming, rowing, and cross country skiing.
  • Concurrent strength and endurance training has been shown to increase the size and fatigue resistance of muscle-fibres as well as increasing the proportion of type IIa and decreasing the proportion of the less fatigue resistant type IIb fibres.
  • Strength training has been shown to significantly enhance exercise efficiency, improve the speed or power output at the lactate threshold, increase fatigue resistance and improve exercise performance.
  • There are four types of strength training that have been demonstrated to enhance exercise performance: heavy resistance training, explosive strength training, core strength training and vibration plate training. Of the four types heavy resistance training and plyometric training are believed to be the most effective.
  • Current research suggests training using weights that can be lifted for 4-10repetitions (approximately 70-85% of 1 repetition maximum). Each workout should consist of 3-10 sets and be completed 2-3 times per week.
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