§5.19Διὰ τί ποτε ἀναβαίνοντες μὲν τὰ γόνατα πονοῦμεν, καταβαίνοντες δὲ τοὺς μηρούς;
Why is it that when ascending we suffer pain in our knees, but when descending in our thighs?
ἢ ὅτι ὅταν μὲν ἀναβαίνωμεν, ἀναρριπτοῦμεν ἄνω τὸ σῶμα, καὶ ἡ σπάσις πολλὴ τοῦ σώματος καὶ ἡ ἀπὸ τῶν γονάτων γίνεται, διὸ πονοῦμεν τὰ γόνατα· ἐν δὲ τοῖς κατάντεσι, διὰ τὸ ὑποφέρεσθαι τοῖς σκέλεσι, τοῖς μηροῖς ἀποστηριζόμενοι πονοῦμεν αὐτούς.
Is it because when we ascend, we fling our body upwards, and the tension of the body is great and that from the knees is also great, wherefore we suffer pain in our knees; whereas in descents, because our legs are carried downwards, we support ourselves with our thighs and so suffer pain in them?
εἶθ’ ἅπαν τὸ παρὰ φύσιν γινόμενον πόνον καὶ λύπην παρασκευάζει.
Furthermore, everything that happens contrary to nature produces pain and distress.
ἔστι δὲ τὸ κατὰ φύσιν τοῖς μὲν γόνασιν ἡ εἰς τὸ πρόσθεν κλάσις, τοῖς δὲ μηροῖς ἡ εἰς τοὔπισθεν.
Now, what is natural for the knees is bending forward, and for the thighs, bending backward.
ἐν μὲν οὖν τοῖς ἀνάντεσι τὰ γόνατα κλᾶται εἰς τοὔπισθεν διὰ τὸ ἀποστηρίζεσθαι βούλεσθαι, ἐν τοῖς κατάντεσι δ’ οἱ μηροὶ εἰς τοὔμπροσθεν κλῶνται διὰ τὸ προπετὲς ἡμῶν εἶναι τὸ σῶμα.
Therefore, in ascents the knees are bent backward because they wish to support themselves, while in descents the thighs are bent forward because our body is leaning forward.
§5.20Διὰ τί ποτε ἐν ταῖς ὁδοῖς τῶν μηρῶν τὸ μέσον μάλιστα πονοῦμεν;
Why is it that in walking we suffer pain most of all in the middle of our thighs?
ἢ ὅτι παντὸς μακροῦ καὶ ἑνὸς ὄντος, ἐστηριγμένου δὲ τοῦ μέσου ὁ πόνος μάλιστα γίνεται;
Is it because in everything that is long and single, when the middle is supported, the pain occurs most of all?
διὸ καὶ κατάγνυται μάλιστα ἐντεῦθεν.
Wherefore also it breaks most of all at that point.
ὁ δὲ μηρός ἐστι τοιοῦτον· διὸ καὶ τὸ μέσον αὐτοῦ μάλιστα πονοῦμεν.
And the thigh is such a thing; wherefore also we suffer pain most of all in its middle.
§5.21Διὰ τί οἱ ὑγροὶ ταχὺ πνίγονται πονήσαντες καὶ ὑπὸ τοῦ καύματος;
Why do moist people quickly become choked when they exert themselves and under the influence of heat?
ἢ ὅτι ἐκθερμαινόμενον τὸ ὑγρὸν ἀὴρ γίνεται, καὶ κάει μᾶλλον τὸ πλέον;
Is it because the moisture, when heated, becomes air, and the greater amount burns more?
ὅταν οὖν μὴ δύνηται ὑπεξάγειν διὰ τὸ πλῆθος, οὐ γίνεται κατάψυξις, ὥστε ταχὺ ἐκπυροῦται ὑπὸ τοῦ συμφύτου καὶ ἐπικτήτου θερμοῦ.
When, therefore, they cannot discharge it because of its abundance, cooling does not take place, so that they are quickly inflamed by their innate and acquired heat.
διὸ καὶ οἱ γινόμενοι ἱδρῶτες τοῖς γυμναζομένοις καὶ ὅλως τοῖς πονοῦσιν καὶ ἡ τοῦ πνεύματος ἔξοδος ὠφέλιμον· διακρινομένου γὰρ καὶ λεπτυνομένου τοῦ ὑγροῦ πνεῦμα γίνεται.
Wherefore also the sweats that occur in those who exercise and generally in those who exert themselves, and the exit of the breath, are beneficial; for when the moisture is separated and thinned, it becomes breath.
§5.22Διὰ τί τὰ σύμμετρα τῶν σωμάτων κάμνει τε πολλάκις καὶ ἀπαλλάττει ῥᾷον;
Why is it that symmetrical bodies both fall ill frequently and recover more easily?
ἢ διὰ ταὐτὸ ἄμφω;
Or is it due to the same cause for both?
ὁμαλὸν γὰρ τὸ σύμμετρον, τὸ δὲ ὁμαλὸν ὁμοπαθέστερον· ἐὰν οὖν τι πονήσῃ μέρος, εὐθὺς συμπονεῖ τὸ ὅλον.
For the symmetrical is uniform, and the uniform is more sympathetic; if, therefore, any part suffers, the whole immediately suffers with it.
τὸ δὲ ἀσύμμετρον, ἅτε μᾶλλον ἀπηρτημένον, οὐ συναπολαύει τῶν μερῶν.
But the asymmetrical, being more disconnected, does not share in the affections of its parts.
κάμνει μὲν οὖν πολλάκις διὰ τοῦτο, ῥᾷον δὲ ἀπαλλάττει, ὅτι πᾶν κοινωνεῖ τὸ σῶμα· εἰς πλείω γὰρ διανεμόμενον τὸ πάθος γίνεται ἀσθενέστερον, ὥστε εὐαπαλλακτότερον.
Thus it falls ill frequently because of this, but recovers more easily because the whole body shares in it; for the affection, being distributed among more parts, becomes weaker, so that it is more easily got rid of.
τὸ δὲ ἀσύμμετρον, ἅτε οὐ κοινωνοῦν τοῖς μέρεσιν, ἐλαττονάκις μὲν κάμνει, χαλεπώτερον δὲ ἀπαλλάττει· σφοδρὸν γὰρ τὸ πάθος.
On the other hand, the asymmetrical body, as it does not share with its parts, falls ill less frequently, but recovers with more difficulty; for the affection is intense.
§5.23Διὰ τί κοπιῶσι μὲν μᾶλλον ἐν τοῖς ὁμαλοῖς ἢ ἐν τοῖς ἀνωμάλοις, θᾶττον δὲ βαδίζουσιν τὴν ὁμαλὴν ἢ τὴν ἀνώμαλον;
Why is it that people get more tired on level ground than on uneven ground, but walk faster on the level than on the uneven?
ἢ ὅτι ἀκοπώτατον μὲν τὸ μὴ ἀεὶ. . . ἐν τῇ ἀνωμάλῳ πορείᾳ μᾶλλον, θᾶττον δὲ πορεύονται, ὅπου ἐν τῷ ἴσῳ χρόνῳ ἐλάττων ἡ ἀναφορά.
Is it because the least tiring thing is not always to [move in the same way], which happens more in uneven walking, whereas they proceed faster where there is less lifting in the same time?
ἐν μὲν οὖν τῷ ὁμαλεῖ μικρὰ ἡ ἄρσις καὶ πυκνή, ἐν δὲ τῷ ἀνωμάλῳ τοὐναντίον.
In the level, then, the lifting is small and frequent, but in the uneven it is the opposite.
τὸ δὲ παρ’ ἑκάστην βάσιν γινόμενον πολὺ γίνεται παρὰ πολλάς.
And that which happens at each single step becomes much after many steps.
§5.24Διὰ τί καταβαίνοντες μὲν τὰ κατάντη τοὺς μηροὺς μάλιστα πονοῦμεν, ἀναβαίνοντες δὲ τὰς κνήμας;
Why is it that when descending slopes we suffer pain most of all in our thighs, but when ascending in our shins?
ἢ ὅτι ἀναβαίνοντες μὲν τῷ αἴρειν τὸ σῶμα;
Is it because when ascending it is due to lifting the body?
ἅπαν γὰρ γίνεται φορτίον τὸ σῶμα.
For the whole body becomes a burden.
ᾧ οὖν ἅπαν ἐπίκειται καὶ ᾧ αἴρομεν, τοῦτο μάλιστα πονεῖ.
That, therefore, on which the whole body presses and with which we lift it, suffers pain most of all.
ἡ δὲ κνήμη τοῦτο.
And the shin is this part.
ἔσχατον γάρ, μῆκος ἔχον, καὶ οὐχ ὥσπερ ὁ ποὺς πλάτος ἔχει· διὸ σαλεύεται.
For it is the extremity, having length, and does not have width like the foot; wherefore it shakes.
ὥστε οἷον τῷ ὤμῳ τὰ βάρη κινοῦμεν, καὶ ἐπὶ τούτῳ ἔχομεν.
So it is as if we move weights with our shoulder, and have them upon it.
τοιγαροῦν καὶ πονοῦμεν τὸν ὦμον μάλιστα.
Therefore we also suffer pain in the shoulder most of all.
καταβαίνοντες δὲ τῷ ἐμπίπτειν τὸ σῶμα κάτω καὶ προωθεῖν παρὰ φύσιν ὁ πόνος ἐστίν, ὥστεᾧ ᾧ μάλιστα ἐπιπίπτει καὶ σαλεύει, τοῦτο παρέχει τὸν πόνον.
But when descending, because the falling of the body downwards and its pushing forward is contrary to nature, the pain arises, so that the part on which the body falls most of all and which shakes, provides the pain.
ἡ μὲν οὖν κνήμη μένει, τὸ δὲ βάρος ὁ θώραξ γίνεται· ὁ δὲ μηρὸς δέχεταί τε καὶ σαλεύεται διὰ τὸ μῆκός τε ἔχειν καὶ στρέφεσθαι ἄνωθεν, ᾗ ὁ θώραξ ἐπιπίπτει.
Therefore, the shin remains firm, while the trunk becomes the burden; and the thigh both receives it and shakes because of its having length and turning from above, where the trunk falls upon it.