You can’t reverse the arrow of time, but according to John Shepherd, the good news for master athletes is that a combined weights and plyometric (mixed) training programme can help offset much of the age-related decline in speed and power capability.
Master athletes are atypical compared to most sedentary adults, who display huge physiological decline over their middle and older years. However, despite this, the body of the master athlete still suffers the ‘typical’ physical decline (albeit far less so) associated with ageing – eg a decline in speed- and power-producing fast-twitch muscle fibres, and an associated declining muscle mass. In this article, we’ll examine the ways that age-related physiological decline can be slowed (and even reversed), with specific reference to speed and power and muscle composition in master athletes.
Sprint times do decline
Sprint times do decline among the world’s elite master sprint performers. This slowdown has been estimated as 5-6% per decade for males and 5-7% per decade for females, with a more significant drop-off occurring between the ages of 65 and 70 (1). With age, muscle mass declines – in particular the proportion of fast-twitch (speed and power producing) muscle fibres. This decline can be by as much as 30% between the ages of 20 and 80 (see figure 1). Fast-twitch fibres literally wither away with age as the nerves that control them die. Looking at total muscle fibre decline – that’s including fast-twitch and slow-twitch fibre – the biceps muscle of a newborn baby, for example, has around 500,000 fibres, but 80 years later these have reduced to 300,000. Why is this important? Well, everything else being equal, a larger muscle can generate greater force. And for those people who (like master sprinters) need speed and power, a decline in fast-twitch fibre count will manifest itself in a decline in these very capacities.Mixed training methods and older people
A number of studies have considered the effects of mixed training methods on older and younger people following the same training protocols. Researchers from Ball State University in the USA analysed the effects of a 10-week mixed training programme on eight young (average age 30) and 10 older men (average age 60) (2). Isometric strength and force development, as measured by a squat jump test, were included in the research. The results were very encouraging for both the older and younger men. It was found that isometric squat strength increased by 23% and 42% respectively for both age groups (the researchers indicated that the young men displayed significantly higher levels of initial isometric strength than their older counterparts, and they used this to explain the statistically very significant increase in the jump performance of the older men).For squat jumps, power outputs were measured using a 17kg load, then loads equivalent to 30% and 60% of the participants’ 1 repetition maximum (1RM). Force output improvements were 14%, 12% and 16% for the young men and 5%, 23% and 16% for the older men. This led the researchers to conclude that: ‘Although the results of this study confirm age-related reductions in muscle strength and power, the older men did demonstrate similar capacity to young men for increases in these variables via an appropriate periodised resistance-training programme that includes rapid, high-power exercises.’
Finnish researchers also used a 10-week mixed programme, comprised of muscle-building and musclepower-increasing weights and plyometric (jumping) exercises, and found similar results (3). Eight young men with an average age of 29, and 10 older men with an average age of 61, participated in the study. Selected findings indicated a maximal isometric strength increase in the young and old men of 15.6% and 16.5% respectively and an increase in the size of the biceps femoris (part of the hamstring muscle group) cross-sectional area by 12.2% and 8.5% respectively.
Mixed training and improved sports performance
Combining weight and plyometric exercises into a mixed training programme can enhance the physical capacity of older people, but can these methods specifically enhance sports performance? Researchers from the University of Jyvaskyla (Finland) analysed the effects of a 20-week mixed training programme on seven 52- to 78-year-old elite male sprinters(4). The subjects were selected because they had no significant prior involvement with intensive strength training. Five master sprinters of similar age and ability acted ascontrols and followed their normal (predominately running-based) training programme.
The sprint-specific training elements
The sprint training workouts were designed to develop acceleration and flat-out running ability. The programme was not too dissimilar from that normally followed by the master sprinters; however the volume was decreased to accommodate the strength-training elements. Slower work was done at the beginning of the 20-week programme, such as 3-5 x 200-250m runs at 75-85% maximum speed, to promote speed-endurance. However, acceleration practices from a standing start were also included – eg 4 x 30m at 80% effort. During the second and third training phases, running intensity was gradually increased until the athletes were running virtually flat out. Relevant workouts included 2-3 x 30-80m sprints at 90-98% effort and starts from blocks were also incorporated.What did the researchers measure?
Restrictions on space preclude a full description of all the battery of tests employed, however they included the following:*Muscle strength – Isometric strength was assessed using a dynamometer and focused on the quadriceps and hamstrings of the dominant leg, while concentric strength was assessed using the 1RM for the half-squat (the athletes attempted to lift maximum weights on this exercise and beat their previous bests over the course of the study).
*Explosive strength – Assessed in three ways:
- By using a force plate and a static jump for height from a 90-degree knee bend;
- By measuring maximum standing triple jump distance;
- By reactive jump ability using straight-leg jumps (keeping the legs as straight as possible, with the majority of the propulsion coming from the calf muscles and the ankles, while attempting to jump as high as possible) performed on a contact mat.
Two 60m sprints were performed from a standing start. Vertical, horizontal, ground reaction forces, contact times and stride rate were recorded using a special 9.4m force platform. The platform was positioned during the maximal speed phase of the 60m run, ie between 30 and 60m out from the start.
EMG activity
During the isometric, concentric strength, and squat jump tests, electromyographic (EMG) activity was measured in the quads and hamstrings of the sprinters’ dominant legs. EMG measures electrical activity in a muscle, basically the more there is the greater the level of muscle fibre recruitment. An increase in EMG can also reflect greater neural stimulation of the muscle (4).Muscle biopsy
Muscle tissue was taken from the middle portion of the vastus lateralis (the large, outer muscle of the quadriceps) of the dominant leg. Muscle biopsies are used to determine the percentage of fast- and slow-twitch muscle fibres in a muscle by inserting a needle into the muscle to extract the fibre, whichis then analysed.
Results
Compared to the control group, isometric muscle strength in the mixed training group increased by 21% and concentric strength by 27%. Meanwhile, explosive strength improved by 10% for the squat jump and reactive power (measured by the straight- legs jump test) improved by 21%. More importantly, the mixed method training programme improved force production during running, which translated into better sprinting performance. There was an 8% increase in force generated during the propulsive phase of the ground contact (the forward push, following foot-strike as the leg extends to drive the sprinter forward), and ground contact time decreased by 9%. Basically, the sprinters spent less time in contact with the ground, which indicates enhanced dynamic ability. Consequently, 60m sprint times improved by 2% from 8.69 sec. to 8.52 sec, and stride length in the maximum speed sprint phase increased from 1.79m to 1.85m.Muscle changes
A 9% increase in the EMG activity of the vastus lateralis and the vastus medialis (another muscle in the quadriceps group) was discovered during the squat jump, but there were no significant changes in the same muscles during the concentric half-squat and the isometric test. The researchers explained the latter by stating that the sprint- trained athletes were not specifically trained nor experienced in generating this type of muscular contraction.However, the researchers did discover a highly significant 20% increase in the cross-sectional area (ie size) of the vastus lateralis. As previously mentioned, a larger muscle is capable of generating more power. Interestingly, slow-twitch type I fibres also displayed a 19% increase in size. These fibres are not known for their ability for hypertrophy (growth) but the mixed training methods stimulated a relevant increase and it is also possible that they contributed to the master sprinters’ improved performances.
Changes were also discovered in the distribution of type IIa and type IIb fast-twitch fibres. Type IIb fibres are those that contribute the most to explosive sports activity, such as a 60m sprint. They are bundled together in the larger motor units and need greater neural stimulation to ‘fire them up’. Type IIa fibres are also known as ‘transitional fibres’, as they have the ability (when subject to relevant training) to take on a greater endurance or power potential. In terms of specific changes to these fibres, increases of 17% and 20% respectively were discovered. Thus the mixed training methodology had the desired effect on stimulating physiological changes at muscular level (ie hypertrophy) that can enhance speed performance – an enhancement not normally associated with an ageing athlete.
The 20-week mixed training programme
The mixed training programme involved an 11- and nine-week training phase. These were further subdivided into three phases of three to four weeks. Basically, the researchers, together with track and field coaches, constructed a systematic, periodised training programme designed to elicit improved sprint speed over time:Phase 1 Involved low-intensity and high-volume exercises to prepare the athletes for the more intense workouts that followed. Typical weights sessions included 3-4 sets of 8-12 repetitions at 50-70% 1RM;
Phases 2 & 3 Involved plyometric, maximal strength and explosive weight training. The weights workouts used low repetitions (4-6) with weights of 70-85% 1RM and the explosive workouts 4-6 equally low, but explosive repetitions at 35-60% 1RM;
Phases 4-6 The workouts in the last three phases were very similar to those performed by the master sprinters in phases 2 and 3, but with a general increase in intensity, which was designed to lift the athletes to optimum sprinting condition.
The exercises involved in the programme were as follows:
Weights
Leg press; half squat, hang pull, stiff-leg dead lift – all using free weights. Fixed weight exercises were also included, such as heel raises, leg extensions and leg curls. Each training session also included 2- 4 other exercises for the arms, chest and the trunk.
Plyometrics
Plyometric exercises progressed from low-intensity ones, such as vertical jumps, to more intense variations, such as bounding.
Combating stride length decline and an increasing contact time
In terms of the technical elements of sprinting, reduced stride length and increased contact time with the track are major factors limiting masters’ sprinting performance. Research from the USA analysed performances of master sprinters and discovered that over time, stride length could actually reduce by as much as 40% between runners in the 35-39 age group and those aged 85-90 (6). Specifically, average stride length reduced from 2.36m to just 1.42m per stride. This could result in the oldest sprinters making virtually twice as many strides as their younger counterparts. Incidentally, the stride rate remained unaffected (a finding that was corroborated by the research that forms the main focus of this article).The Finnish findings on mixed training methods have some very important implications for master sprinters in terms of the technical excutuion of the sprint running action, in so far as it would appear that this training methodology can actually combat the major detriminal age-related factors of reduced performance.
John Shepherd MA is a specialist health, sport and fitness writer and a former international long jumper
References
1 Med Sci Sports Exerc 2003 Aug; 35 (8): 1419-28
2 Med Sci Sports Exerc. 2002 Aug;34(8):1367-75
3 J Gerontol A Biol Sci Med Sci. 1998 Nov;53(6):B415-23.
4 Acta Physiol 2008. 193, 275-289
5 Muscle Nerve 31, 355-364
6 J of App Biom 1993 (9) pp 15-26