Faculty of Biological Sciences

Dr Graham Askew

BSc, PhD 1995, Leeds
Associate Professsor in Muscle Function & Movement
School of Biomedical Sciences

Contact:  Garstang 5.55a | +44(0) 113 34 32897 | email address for  

Mechanics and Energetics of Locomotion. The overall goal of the lab is to understand muscle function within the context of whole animal movement. Muscle mechanics and energetics underpin our understanding of animal (including human) locomotion. My current research uses an integrative approach to track the flow of energy from the contractile proteins within the muscle to the environment, linking metabolic inputs with mechanical outputs.

Mechanical function of muscles during locomotion. Muscle length change and activity patterns are measured during locomotion, and combined with physiological measurements to determine muscle mechanical performance (e.g. force or power output).

Pectoralis fascicle strain and EMG activity
In vivo zebra finch pectoralis fascicle strain and EMG activity at 10 m s-1. Fascicle length was measured by sonomicrometry. Muscle activity was measured using a bipolar EMG electrode.

Recent work has examined how small birds modulate pectoral muscle power production across a range of flight speeds. Their pectoral muscles contain a single muscle fibre type, so they are unable to vary muscle power output by recruiting motor units with different physiological properties. Instead, we found that the power output can be modulated by changing the muscle length trajectory and the relative timing and intensity of muscle activity (Askew and Ellerby, 2007; Ellerby and Askew 2007; Morris and Askew, 2010).

Energetics of Locomotion A variety of approaches are used to tease apart the underlying processes that determine the overall cost of locomotion. Whole organism metabolic rate is determined by measuring O2 consumption and CO2 production during locomotion (Fig. 2; Morris and Askew, 2010; Askew et al., 2011). At the level of the muscle, energy use can be quantified by measuring the total enthalpy output (the sum of the mechanical work and heat production) and also, indirectly, by measuring regional blood flow. Energy use can also be quantified at the level of the cross-bridges (Askew et al., 2010).

Using respirometry to measure metabolic energy expenditure during locomotion - while walking in Medieval armour and during flight in a cockatiel.

In recent work we have investigated how the mechanical power output relates to the metabolic energy consumed by birds during flight to estimate the flight efficiency (Morris et al., 2010). We have also used modern physiology to quantify the costs of moving in Medieval armour to investigate whether this could have affected soldiers’ locomotor performance  and potentially influenced the outcomes of past medieval battles (Askew et al., 2011).

Funding. Research in my laboratory is funded by the BBSRC, EPSRC and the Royal Society. 

Recent research highlights. How birds power flight http://jeb.biologists.org/content/213/16/i.full 

Energetics of locomotion in Medieval armour (Proceedings of the Royal Society B July 2011); Science: news.sciencemag.org/sciencenow/2011/07/heavy-armor-gave-knights-a-worko.html BBC News: www.bbc.co.uk/news/science-environment-14204717 LiveScience: www.livescience.com/15128-armor-drained-medieval-knight-energy.html

Latest: PhD Studentship available on "The energetics of bird flight: metabolic, mechanical and aerodynamic consequences of flying in formation". See findaphd.com 

Current Projects

  1. Insect flight energetics
  2. Bird flight energetics and the efficiency of the flight muscles
  3. Take-off performance and manoeuvrability of birds and bats
  4. Muscle physiology and energetics
  5. Invertebrate swimming: muscle physiology, fluid dynamics

Faculty Research and Innovation

Studentship information

Undergraduate project topics:

  • Mechanics and energetics of locomotion
  • Determinants of route selection
  • Breathing mechanics
  • Sport related aerodynamics
  • Invertebrate swimming
  • Thermography as an index of energy expenditure

Postgraduate studentship areas:

  • Muscle performance and energetics during locomotion. Bird, bat and insect flight. Inveretbrate swimming. Scaling of muscle performance. Manoeuvrability.

See also:

Admin roles

FBS Graduate School Committee

Modules taught

BIOC2201/SPSC2201 - Exercise Biochemistry
BLGY2330 - Terrestrial Ecology and Behaviour Field Course
BMSC1110/SPSC1220 - Foundation modules
SPSC2302 - Exercise Physiology in Sport, Health and Disease
SPSC2304 - Mechanics of Sport and Exercise 2
SPSC2304/2213 - Mechanics of Sport and Exercise
SPSC3061 - Research Project in Sport and Exercise Science II


Member of Graduate School Committee

Centre membership: The Earth and Biosphere Institute

Group Leader Dr Graham Askew  (Associate Professsor in Muscle Function & Movement)

Dr Peter Tickle  (Research Fellow)


Alexander Evans  
Nicholas Gladman  
Marion Kauffmann  
Roger Kissane  
Laura McFarlane  
Zak Mitchell  
Thomas Neil  
Katie Nicoll Baines  

Askew GN; Formenti F; Minetti AE Limitations imposed by wearing armour on Medieval soldiers' locomotor performance. Proc Biol Sci 279 640-644, 2012
View abstract

Morris CR; Askew GN The mechanical power output of the pectoralis muscle of cockatiel (Nymphicus hollandicus): the in vivo muscle length trajectory and activity patterns and their implications for power modulation J EXP BIOL 213 2770-2780, 2010

Morris CR; Nelson FE; Askew GN The metabolic power requirements of flight and estimations of flight muscle efficiency in the cockatiel (Nymphicus hollandicus) J EXP BIOL 213 2788-2796, 2010

Morris CR; Askew GN Comparison between mechanical power requirements of flight estimated using an aerodynamic model and in vitro muscle performance in the cockatiel (Nymphicus hollandicus) J EXP BIOL 213 2781-2787, 2010

Askew GN; Tregear RT; Ellington CP The scaling of myofibrillar actomyosin ATPase activity in apid bee flight muscle in relation to hovering flight energetics J EXP BIOL 213 1195-1206, 2010

Miller G; Neilan M; Chia R; Gheryani N; Holt N; Charbit A; Wells S; Tucci V; Lalanne Z; Denny P; Fisher EMC; Cheeseman M; Askew GN; Dear TN ENU Mutagenesis Reveals a Novel Phenotype of Reduced Limb Strength in Mice Lacking Fibrillin 2 PLOS ONE 5 -, 2010

Holt NC; Roberts TJ; Askew GN The energetic benefits of tendon springs in running: is the reduction of muscle work important? The Journal of experimental biology -, 2014
View abstract

Askew GN The elaborate plumage in peacocks is not such a drag JOURNAL OF EXPERIMENTAL BIOLOGY 217 3237-3241, 2014

Holt NC; Askew GN Locomotion on a slope in leaf-cutter ants: metabolic energy use, behavioural adaptations and the implications for route selection on hilly terrain. J Exp Biol 215 2545-2550, 2012
View abstract

Holt NC; Askew GN The effects of asymmetric length trajectories on the initial mechanical efficiency of mouse soleus muscles. J Exp Biol 215 324-330, 2012
View abstract

Ellerby DJ; Askew GN Modulation of pectoralis muscle function in budgerigars Melopsitaccus undulatus and zebra finches Taeniopygia guttata in response to changing flight speed J EXP BIOL 210 3789-3797, 2007

Ellerby DJ; Askew GN Modulation of flight muscle power output in budgerigars Melopsittacus undulatus and zebra finches Taeniopygia guttata: in vitro muscle performance J EXP BIOL 210 3780-3788, 2007

Askew GN; Ellerby DJ The mechanical power requirements of avian flight BIOLOGY LETT 3 445-448, 2007

West TG; Donohoe PH; Staples JF; Askew GN Tribute to R.G. Boutilier: The role for skeletal muscle in the hypoxia-induced hypometabolic responses of submerged frogs J EXP BIOL 209 1159-1168, 2006

James RS; Wilson RS; Askew GN Effects of caffeine on mouse skeletal muscle power output during recovery from fatigue J APPL PHYSIOL 96 545-552, 2004

Askew GN; Marsh RL Muscle designed for maximum short-term power output: quail flight muscle. J Exp Biol 205 2153-2160, 2002
View abstract

Askew GN; Cox VM; Altringham JD; Goldspink DF Mechanical properties of the latissimus dorsi muscle after cyclic training Journal of Applied Physiology 93 649-659, 2002

Askew GN; Marsh RL; Ellington CP The mechanical power output of the flight muscles of blue-breasted quail (Coturnix chinensis) during take-off. J Exp Biol 204 3601-3619, 2001
View abstract

Askew GN; Marsh RL The mechanical power output of the pectoralis muscle of blue-breasted quail (Coturnix chinensis): the in vivo length cycle and its implications for muscle performance. J Exp Biol 204 3587-3600, 2001
View abstract

Askew GN; Marsh RL Optimal relative shortening velocity (V/Vmax) of skeletal muscle during cyclical contractions: length-force effects and velocity dependent activation and deactivation Journal of Experimental Biology 201 1527-1540, 1998

Askew GN; Young IS; Altringham JD Fatigue of mouse soleus muscle using the work loop technique Journal of Experimental Biology 200 2907-2912, 1997

Askew GN; Marsh RL The effects of length trajectory on the mechanical power output of mouse skeletal muscles Journal of Experimental Biology 200 3119-3131, 1997