§5.8Διὰ τί κοπιαρώτερόν ἐστι τῷ βραχίονι τὸ διὰ κενῆς ῥίπτειν ἢ λιθάζοντα;
Why is it more tiring for the arm to throw in the empty air than when throwing a stone?
ἢ ὅτι σπασματωδέστερον τὸ διὰ κενῆς ἐστίν;
Is it because throwing in the empty air is more spasmodic?
οὐ γὰρ ἀπερείδεται πρὸς οὐδέν, ὥσπερ ὁ βάλλων πρὸς τὸ ἐν τῇ χειρὶ βέλος.
For it does not support itself against anything, as a thrower does against the missile in his hand.
ὁμοίως δὲ τούτῳ καὶ ὁ πένταθλος πρὸς τοὺς ἁλτῆρας καὶ ὁ θέων παρασείων πρὸς τὰς χεῖρας.
And similarly to this, both the pentathlete with regard to the halteres and the runner swinging his arms with regard to his hands.
διὸ ὁ μὲν μεῖζον ἅλλεται ἔχων ἢ μὴ ἔχων ἁλλῆρας, ὁ δὲ θᾶττον θεῖ παρασείων ἢ μὴ παρασείων.
Therefore, the former jumps further having halteres than not having them, and the latter runs faster swinging his arms than not swinging them.
§5.9Διὰ τί ἡ ταχυδρομία καὶ ἔπ’ ἀνθρώπου καὶ ἐπὶ τῶν ἄλλων ζῴων νοσηματικοὺς ποιεῖ τὰ περὶ τὴν κεφαλήν;
Why does fast running, both in the case of man and of other animals, make the parts around the head prone to disease?
καίτοι ὅλως ὁ δρόμος κατασπᾶν δοκεῖ κάτω τὰ περιττώματα, ὥσπερ ὁ περίπατος· διὸ καὶ παχύνονται τὰ σκέλη οἱ πολλὰ περιπατοῦντες, ὅτι εἰς τὰ κάτω ὑπονοστεῖ ἄνωθεν καὶ ἡ τροφὴ καὶ τὰ περιττώματα.
And yet, running in general seems to draw down residues, just as walking does; wherefore those who walk much get thick legs, because both food and residues sink downwards from above.
ἢ ἡ μὲν κίνησις ταὐτὸ ποιεῖ, ἀλλ’ ἡ ταχεῖα διὰ τὴν συντονίαν καὶ τὴν ἀπνευστίαν ἐκθερμαίνει τὴν κεφαλήν, καὶ τὰς φλέβας ἐμφυσᾷ τὰς ἐν αὐτῇ, καὶ σπαστικὰς τῶν θύραθεν ποιεῖ δυνάμεων, οἷον ψύχους καὶ ἀλέας καὶ τῶν ἐκ τοῦ θώρακος, ὧν εἰσιόντων νοσεῖν ἀναγκαῖον τὸν τόπον ἐστίν.
Or does movement indeed do the same, but fast movement, because of the tension and breathlessness, heats the head, and inflates the veins in it, and makes them susceptible to external influences, such as cold and heat and those from the chest, upon the entry of which it is necessary for the place to become diseased?
§5.10Διὰ τί κοπιῶσι μὲν μᾶλλον ἐν τοῖς ὁμαλοῖς ἢ ἐν τοῖς ἀνωμάλοις τόποις, θᾶττον δὲ βαδίζουσιν τὴν ὁμαλὴν ὁδὸν ἢ τὴν ἀνώμαλον;
Why do they fatigue more on level than on uneven ground, but walk faster on a level road than on an uneven one?
ἢ ὅτι ἀκοπώτερον μέν ἐστι τὸ μὴ ἀεὶ ἐν τῷ αὐτῷ σχήματι ποιεῖσθαι τὴν κίνησιν, ὃ συμβαίνει ἐν τῇ ἀνωμάλῳ πορείᾳ μᾶλλον;
Is it because it is less tiring not to make the movement always in the same posture, which occurs more in uneven walking?
θᾶττον γὰρ πορεύονται, ὅτι ἧττον παρὰ φύσιν κινοῦνται.
And they proceed faster because they move less contrary to nature.
ἐν μὲν οὖν τῷ ὁμαλῷ μικρὰ ἡ ἄρσις καὶ θέσις καὶ πυκνή ἐστιν, ἐν δὲ τῷ ἀνωμάλῳ τοὐναντίον.
On level ground, indeed, the lifting and placing of the feet is small and frequent, but on uneven ground the opposite.
ἔστι δὲ τὸ αἴρειν παρὰ φύσιν· βίᾳ γάρ ἐστι πᾶσα ἄρσις.
But lifting is contrary to nature; for all lifting is by force.
τὸ δὲ παρ’ ἑκάστην βάσιν γινόμενον μικρὸν πολὺ γίνεται παρὰ πολλάς.
And the small amount occurring at each step becomes much over many steps.
§5.11Διὰ τί τὰ ἐπίπεδα κοπιαρώτερα ἐγκατακεῖσθαι τῶν κοίλων ἐστίν;
Why are flat surfaces more tiring to lie down on than hollow ones?
ἢ διὰ τὸ αὐτὸ καὶ τὰ κυρτὰ τῶν ἐπιπέδων;
Is it for the same reason that convex surfaces are more so than flat ones?
ἐφ’ ἕνα γὰρ τόπον συναθροιζόμενον τὸ βάρος ἐν τῇ καθέδρᾳ ἢ κατακλίσει τῇ θλίψει ποιεῖ πόνον.
For the weight being gathered to one place in sitting or lying down produces pain by pressure.
τὸ μὲν οὖν κυρτὸν τοῦ εὐθέος, τοῦτο δὲ τοῦ κοίλου μᾶλλον τοιοῦτόν ἐστι· τὸ γὰρ σῶμα ἡμῶν ἐστὶ περιφερέστερον ἢ εὐθύτερον, τῶν δὲ τοιούτων κατὰ πλέον ἅπτεται τὰ κοῖλα ἢ τὰ ἐπίπεδα.
Now the convex is more so than the flat, and the flat more so than the hollow; for our body is more rounded than straight, and hollow surfaces touch such bodies more than flat ones.
διὰ ταῦτα δὲ καὶ τὰ ἐνδιδόντα τῶν μὴ ἐνδιδόντων ἀκοπώτερά ἐστι καὶ ἐγκατακλιθῆναι καὶ ἐνέζεσθαι.
For these reasons also, yielding surfaces are less tiring than unyielding ones both to lie down on and to sit on.
§5.12Διὰ τί οἱ βραχεῖς περίπατοι κοπώδεις εἰσίν;
Why are short walks tiring?
ἢ ὅτι ἀνώμαλοί εἰσι;
Is it because they are uneven?
πολλάκις γὰρ ἵστασθαι ποιοῦσιν.
For they make one stop often.
τὸ δ’ ἐκ τοῦ ἐναντίου εἰς τοὐναντίον πυκνὰ μεταβάλλειν κοπῶδές ἐστιν· συνήθειαν γὰρ οὐδετέρῳ ποιεῖ, ὅ ἐστιν ἄκοπον. ἀμφοῖν δ’ ἅμα οὐκ ἐνδέχεται συνήθειαν γίνεσθαι.
And to change frequently from one opposite to another is tiring, for it produces habituation to neither, which is what is untiring; and it is impossible for habituation to both to occur at the same time.
§5.13Διὰ τί οἱ ἐπὶ τῶν ἵππων ὀχούμενοι, ὅσῳ ἂν μᾶλλον θέῃ ὁ ἵππος, τοσούτῳ μᾶλλον δακρύουσι τὰ ὄμματα;
Why is it that those who ride on horses, the more the horse runs, the more they shed tears from their eyes?
πότερον διὰ τὸ ψυχρότερον εἶναι τὸν ἀεὶ προσπίπτοντα ἀέρα, ὅσῳ ἂν ἐλάττω χρόνον ἅπτηται τοῦ σώματος, ὅπερ ἐπὶ τῶν γυμνῶν θεόντων συμβαίνει;
Is it because the air constantly falling upon them is colder, the less time it touches the body, which happens to those running naked?
τὸ δὲ ψῦχος δάκρυον ποιεῖ.
And cold produces tears.
ἢ διὰ τοὐναντίον;
Or is it for the opposite reason?
καὶ γὰρ τὸ θερμὸν ποιεῖ δακρύειν, οἷον ὁ ἥλιος· ἡ δὲ κίνησις θερμότητα ποιεῖ.
For hot things also make one shed tears, such as the sun; and movement produces heat.
ἢ διὰ τὴν ὑπὸ τοῦ ἀέρος πληγήν;
Or is it because of the blow of the air?
ὡς γὰρ οἱ ἄνεμοι ταράττουσιν οἱ ἐξ ἐναντίας τὰ ὄμματα, οὕτως ὁ ἀὴρ προσπίπτων, ὅσῳ ἂν θᾶττον ἐλαύνῃ, τοσούτῳ μᾶλλον ποιεῖ πληγὴν μαλακήν.
For as winds from the opposite direction trouble the eyes, so the falling air, the faster one rides, the more it produces a soft blow.